Type species

Appendisphaera grandis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, emend. Moczydłowska, Reference Moczydłowska2005.

Other species

Appendisphaera anguina Grey, Reference Grey2005; A.? brevispina Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; A. clava Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; A. clustera Liu and Moczydłowska, Reference Liu and Moczydłowska2019; A. fragilis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993; A. heliaca (Liu and Moczydłowska, Reference Liu and Moczydłowska2019) Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021; A.? hemisphaerica Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; A. lemniscata Liu and Moczydłowska, Reference Liu and Moczydłowska2019; A. longispina Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; A. longitubularis (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) Liu and Moczydłowska, Reference Liu and Moczydłowska2019; A. magnifica (Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998) Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; A. setosa Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; A. tabifica Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993; A. tenuis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993.

Remarks

The latest emendation diagnoses Appendisphaera as a genus of acanthomorphic acritarch with “simple, homomorphic, slim, cylindrical or ciliate” processes, which can be either straight or tapering, and can have a basal expansion and a rounded or blunt termination (Moczydłowska, Reference Moczydłowska2005, p. 293). These features, however, are found in many other genera such as Cavaspina, Knollisphaeridium, Tanarium, and even Xenosphaera. Therefore, systematic morphometric work is required to develop a practical workflow to distinguish these taxa, including Appendisphaera, that fall into the category of “acanthomorphs with hollow, tapering, conical processes” by Grey (Reference Grey2005, p. 172–175).

Appendisphaera grandis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, emend. Moczydłowska, Reference Moczydłowska2005
Figure 4

Figure 4. Appendisphaera grandis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, emend. Moczydłowska, Reference Moczydłowska2005. (1, 2) PB201998, thin section 18JSC-2-5, U40/4; circled 2 in (1) marks area magnified in (2). (3, 4) PB201999, thin section 19HP-1-33, N41/1; circled 4 in (3) marks area magnified in (4). (5, 6) PB202000, thin section 19TP-1-19, D49/4; circled 6 in (5) marks area magnified in (6). (7–9) PB202001, thin section 19SDP-2-d1, Y24/1; circled 8 and 9 in (7) mark areas magnified in (8) and (9), respectively. (10, 11) PB202002, thin section 21DC-5-4, V34/1; circled 11 in (10) marks area magnified in (11).

Reference Moczydłowska, Vidal and Rudavskaya1993

Appendisphaera grandis Moczydłowska, Vidal, and Rudavskaya, p. 503, text-fig. 5, pl. 1, figs. 1, 2.

Reference Moczydłowska2005

Appendisphaera grandis Moczydłowska et al.; Moczydłowska, p. 294, figs. 3, 4.

Reference Knoll, Javaux, Hewitt and Cohen2006a

Appendisphaera grandis; Knoll et al., fig. 3g.

Reference Moczydłowska2008

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Willman and Moczydłowska, p. 519, fig. 6C.

Reference Chen, Yin, Liu, Gao, Tang and Wang2010

Appendisphaera grandis; Chen et al., fig. 2.1.

Reference Golubkova, Raevskaya and Kuznetsov2010

Appendisphaera grandis Moczydłowska et al.; Golubkova et al., pl. 1, fig. 1, pl. 3, figs 4, 10.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Xiao et al., p. 9, fig. 3.1–3.3.

non Reference Shukla and Tiwari2014

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Shukla and Tiwari, p. 215, fig. 4D, E.

Reference Nagovitsin and Kochnev2015

Appendisphaera grandis Moczydlowska et al. [sic]; Nagovitsin and Kochnev, fig. 4.I.1, 4.I.2.

Reference Prasad and Asher2016

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Prasad and Asher, p. 42, pl. II, figs. 3, 4.

Reference Anderson, Macdonald, Jones, McMahon and Briggs2017

Appendisphaera grandis; Anderson et al., fig. 2B.

Reference Hawkins, Xiao, Jiang, Wang and Shi2017

Appendisphaera crebra; Hawkins et al., fig. 9E, F.

Reference Ouyang, Guan, Zhou and Xiao2017

Appendisphaera fragilis; Ouyang et al., fig. 8D–F.

Reference Anderson, McMahon, Macdonald, Jones and Briggs2019

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Anderson et al., p. 507, fig. 6A–D.

Reference Liu and Moczydłowska2019

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Liu and Moczydłowska, p. 48, figs. 21–23.

Reference Ouyang, Zhou, Xiao, Chen and Shao2019

Appendisphaera grandis; Ouyang et al., fig. 8I–K.

Reference Shang, Liu and Moczydłowska2019

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Shang et al., p. 7, fig. 3.

Reference Ouyang, Zhou, Xiao, Chen and Shao2019

Appendisphaera clava; Ouyang et al., fig. 8E, F.

Reference Shang and Liu2020

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Shang and Liu, p. 156, fig. 4.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Ouyang et al., fig. 10M–P.

non Reference Liu, Qi, Fan, Guo and Pei2021

Appendisphaera grandis; Liu et al., fig. 5.4.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Shi et al., fig. 7A, B.

Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Xiao et al., fig. 7.

Reference Ye, Li, Tong, An, Hu and Xiao2022

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Ye et al., fig. 10A–D.

non Reference Ye, Li, Tong, An, Hu and Xiao2022

Appendisphaera grandis Moczydłowska et al., emend. Moczydłowska; Ye et al., fig. 10E, F.

Reference Golubkova2023

Appendisphaera grandis (Moczydłowska et al.) emend. Moczydłowska; Golubkova, pl. 7, fig. 1.

Holotype

PMU-Sib.1-R/63/2, reposited at Uppsala University, from the Ediacaran Khamaka Formation, Nepa–Botuoba region, Yakutia, Siberia (Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, p. 503, text-fig. 5A–D).

Description and measurements

Vesicle mostly compressed but originally spheroidal, medium to large in size, bearing numerous, evenly and densely distributed processes. Processes hollow, long and slim, cylindrical for most part, lack significant basal expansion. Three least-deformed specimens yield vesicle diameters of ~152–373 μm. Approximately 12–28 processes per 100 μm of vesicle periphery. Full length of processes difficult to measure due to deformation but estimated to exceed 20 μm and making up >10% of vesicle diameter (18.5–39.5 μm, 9.0–12.2% of vesicle diameter). Process width 0.1–1.3 μm (N = 8, mean = 0.6 μm, SD = 0.4 μm).

Remarks

As for the type species of Appendisphaera, A. grandis was initially distinguished by its proportionally long and hair-like processes (Moczydłowska et al., Reference Moczydłowska, Vidal and Rudavskaya1993), but the processes were later found to be hollow and cylindrical (Moczydłowska, Reference Moczydłowska2005). Measurements on photos of the eight A. grandis specimens from its type locality published by Moczydłowska et al. (Reference Moczydłowska, Vidal and Rudavskaya1993) and Moczydłowska (Reference Moczydłowska2005) reveal relatively small morphological variations: small to medium-sized vesicle (diameter 77–130 μm, mean = 107 μm, SD = 16 μm), relatively long and thin processes (process length 12.0–25.3 μm, mean = 18.4 μm, SD = 5.4 μm; process length to vesicle diameter ratio 10.8–23.0%, mean = 17.2%, SD = 4.7%; process basal width 0.4–1.8 μm, mean = 1.2 μm, SD = 0.4 μm), and large process density (46–65 processes per 100 μm of vesicle periphery, but this may be an overestimation since these eight specimens are all preserved as carbonaceous compressions). In summary, the processes of A. grandis from the type locality make up almost 20% of vesicle diameter and are so thin (basal width ~1 μm) that their shape is better described as cylindrical than conical, even though gradual terminal tapering can be observed on both holotype and paratype of this species.

With additional specimens assigned to this species in recent years (especially permineralized specimens), the morphospace of A. grandis has grown rapidly. Appendisphaera grandis currently contains specimens with a large vesicle (diameter up to several hundred microns) and process lengths about 10% of vesicle diameter. Despite this, A. grandis is still characterized by its relatively long, thin, and almost cylindrical processes, which differentiates it from other Appendisphaera species with relatively short processes (e.g., A. clava and A. tenuis) and those species with basally expanded processes (e.g., A. longitubularis, A. longispina, and A. magnifica; see also remarks under A. magnifica). In this study, only specimens with process basal width around 1 μm and no more than 2 μm, and process proportional length greater than 10% of vesicle diameter are accepted as A. grandis. Based on these criteria, the specimen illustrated by Liu et al. (Reference Liu, Qi, Fan, Guo and Pei2021, fig. 5.4) is removed from A. grandis. Its long, thick, terminally cylindrical processes resemble those of A. longitubularis and Tanarium gracilentum (Yin in Yin and Liu, Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988) Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021, which also have distally tapered and densely arranged processes. Similarly, the specimen illustrated as A. grandis by Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 10E, F), bearing apparently conical processes with a basal width exceeding 5 μm, is more appropriately placed in A. longispina.

Appendisphaera magnifica (Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998) Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a
Figure 5

Reference Zhang, Yin, Xiao and Knoll1998

Meghystrichosphaeridium magnificum Zhang et al., p. 36, fig. 10.5, 10.6.

?Reference Zhou, Xie, McFadden, Xiao and Yuan2007

Meghystrichosphaeridium magnificum; Zhou et al., fig. 4E.

Reference Yin, Wang, Yuan and Zhou2011

Meghystrichosphaeridium magnificum; C. Yin et al., fig. 5d.

Reference Liu, Yin, Chen, Tang and Gao2013

Meghystrichosphaeridium magnificum Zhang et al.; Liu et al., fig. 11I, J.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Appendisphaera magnifica (Zhang et al.), Liu et al., p. 21, figs. 5.8, 19.1–19.6, 20.1–20.6.

Reference Ouyang, Zhou, Guan and Wang2015

Appendisphaera magnifica (Zhang et al.) Liu et al.; Ouyang et al., p. 215, pl. I, figs. 1, 2, 4.

Reference Hawkins, Xiao, Jiang, Wang and Shi2017

Appendisphaera magnifica; Hawkins et al., fig. 9A, B.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Appendisphaera magnifica (Zhang et al.) Liu et al.; Ouyang et al., fig. 11I, J.

Figure 5. Appendisphaera magnifica (Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998) Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a. (1) PB202003, thin section 19SDP-7-1, N38/3. (2) PB202004, thin section 19SDP-7-3, E39/2. (3) PB202005, thin section 19SDP-7-3, E30/2. (4) PB202006, thin section 19SDP-7-3, K30/2. (5) PB202007, thin section 19SDP-7-24, H37. (6) PB202008, thin section 19SDP-7-24, H34.

Holotype

WCHB-789b-24, reposited at Peking University Paleontological Collection, from the Ediacaran Doushantuo Formation, Weng'an area, Guizhou Province, South China (Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998, p. 36, fig. 10.5, 10.6).

Description and measurements

Vesicle medium-sized, originally spheroidal but some deformed to varying degrees. Processes uniformly conical, long, and thin, tapering gradually toward the terminal end, evenly and densely arranged on the vesicle, basally separate. Vesicle diameter 98–167 μm (N = 16, mean = 132 μm, SD = 19 μm); process length 12.2–26.3 μm (N = 17, mean = 18.6 μm, SD = 3.8 μm), 9.5–21.3% of vesicle diameter (N = 16, mean = 14.2%, SD = 3.0%), process basal width 2.0–4.9 μm (N = 17, mean = 3.0 μm, SD = 0.8 μm); 16–30 processes (N = 16, mean = 22, SD = 4) per 100 μm of vesicle periphery.

Material

Six illustrated specimens (Fig. 5) and 11 additional specimens.

Remarks

The 17 specimens described here are similar to the holotype of Appendisphaera magnifica in the closely arranged, basally separate, and acutely tapering processes. But they are significantly smaller than the holotype, whose vesicle diameter is about 350 μm. However, they are similar to the A. magnifica specimens in Liu et al. (Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) in dimensions, with the latter yielding a vesicle diameter of 100–160 μm, process length of 19–36 μm (14–30% of vesicle diameter), process basal width of 2.1–3.4 μm, and 20–24 processes per 100 μm of vesicle periphery.

Liu et al. (Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) transferred “Meghystrichosphaeridium” magnificum to Appendisphaera, on the basis of its very thin and densely distributed processes. However, Liu and Moczydłowska (Reference Liu and Moczydłowska2019) synonymized Appendisphaera magnifica with A. grandis without justification. Appendisphaera is one of the richly speciose genera of Ediacaran acanthomorphs (Xiao et al., Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022), and the differentiation of species within this genus has become a problem. Morphological analysis of the Cambrian acanthomorphic genus Skiagia indicates that morphological variation of this richly speciose genus may reflect phenotypic plasticity (Wallet et al., Reference Wallet, Willman and Slater2022). The same can be said of Appendisphaera, and it is possible that A. magnifica and A. grandis are synonymous. Although A. magnifica and A. grandis do share morphological similarities (e.g., process density, proportional length), the processes of A. magnifica have a relatively wider base, making its processes more conical in shape and different from the more cylindrical processes of A. grandis (Moczydłowska, Reference Moczydłowska2005). Post-mortem degradation or deformation may cause process shrinkage and account for the thinner processes of A. grandis, but there are many delicately preserved specimens of A. grandis, both permineralized (e.g., Liu and Moczydłowska, Reference Liu and Moczydłowska2019, figs. 21, 22) and preserved as carbonaceous compressions (e.g., type specimens from Siberia, Moczydłowska et al. Reference Moczydłowska, Vidal and Rudavskaya1993) that are unlikely to be deformed variants of A. magnifica. Thus, we retain A. magnifica as a distinct form species.

Appendisphaera tenuis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, emend. Moczydłowska, Reference Moczydłowska2005
Figure 6

Reference Moczydłowska, Vidal and Rudavskaya1993

Appendisphaera tenuis Moczydłowska, Vidal, and Rudavskaya, p. 506, text-fig. 7.

Reference Nagovitsin, Faizullin and Yakshin2004

Appendisphaera minima Nagovitsin and Faizullin in Nagovitsin et al., p. 12, pl. I, figs. 1–3.

Reference Grey2005

Appendisphaera tenuis Moczydłowska et al.; Grey, p. 224, figs. 88F, 113A–D.

Reference Moczydłowska2005

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska, p. 296, fig. 5.

Reference Grey2005

Ericiasphaera polystacha Grey, p. 264, figs. 169, 170.

non Reference Yin, Zhu, Knoll, Yuan, Zhang and Hu2007

Appendisphaera tenuis; Yin et al., fig. 1b.

?Reference Vorob'eva, Sergeev and Chumakov2008

Appendisphaera tenuis Moczydłowska; Vorob'eva et al., fig. 2k, l.

Reference Willman and Moczydłowska2008

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Willman and Moczydłowska, p. 520, figs. 7B, C, 8A, B.

Reference Golubkova, Raevskaya and Kuznetsov2010

Appendisphaera tenuis Moczydłowska et al.; Golubkova et al., pl. I, fig. 2, pl. III, figs. 5, 6.

?Reference Golubkova, Raevskaya and Kuznetsov2010

Ericiasphaera aff. E. addspersa Grey; Golubkova et al., pl. IV, fig. 6a, b.

Reference Sergeev, Knoll and Vorob'eva2011

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Sergeev et al., p. 1002, fig. 5.4–5.6.

?Reference Willman and Moczydłowska2011

Cavaspina amplitudinis Willman in Willman and Moczydłowska, p. 25, pl. I, figs. 1–6.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Liu et al., p. 31, fig. 23.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Xiao et al., p. 9, fig. 3.4.

Reference Shukla and Tiwari2014

Appendisphaera grandis; Shukla and Tiwari, p. 215, fig. 4D, E.

Reference Golubkova, Zaitseva, Kuznetsov, Dovzhikova and Maslov2015

Appendisphaera tenuis Moczydłowska et al.; Golubkova et al., fig. 2a.

Reference Nagovitsin and Kochnev2015

Appendisphaera tenuis Moczydlowska [sic]; Nagovitsin and Kochnev, fig. 4.I.3.

?Reference Ye, Tong, An, Tian, Zhao and Zhu2015

Appendisphaera sp.; Ye et al., p. 48, pl. I, figs. 9–14.

Reference Prasad and Asher2016

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Prasad and Asher, p. 44, pl. III, figs. 3–6.

Reference Prasad and Asher2016

Gyalosphaeridium multispinulosum Grey; Prasad and Asher, p. 52, pl. VI, figs. 3, 4.

Reference Prasad and Asher2016

Gyalosphaeridium pulchrum Zang in Zang and Walter; Prasad and Asher, p. 52, pl. VI, figs. 5, 6.

Reference Liu and Moczydłowska2019

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Liu and Moczydłowska, p. 61, figs. 29, 30.

Reference Anderson, McMahon, Macdonald, Jones and Briggs2019

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Anderson et al., p. 509, fig. 6H, I.

Reference Shang, Liu and Moczydłowska2019

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Shang et al., p. 10, fig. 5.

Reference Shang, Liu and Liu2020

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Shang and Liu, p. 157, fig. 5A, B.

Reference Vorob'eva and Petrov2020

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Vorob'eva and Petrov, p. 370, pl. I, figs. 3, 4.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Ouyang et al., fig. 11Q, R.

Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Xiao et al., fig. 17.

Reference Ye, Li, Tong, An, Hu and Xiao2022

Appendisphaera tenuis Moczydłowska et al., emend. Moczydłowska; Ye et al., fig. 12E, F.

Reference Golubkova2023

Appendisphaera tenuis (Moczydłowska et al.) emend. Moczydłowska; Golubkova, pl. 7, fig. 2.

Figure 6. Appendisphaera tenuis Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, emend. Moczydłowska, Reference Moczydłowska2005. (1, 2) PB202009, thin section 19TP-1-14, J27; circled 2 in (1) marks area magnified in (2). (3–5) PB202010, thin section 19TP-1-39, J47/1; circled 4 and 5 in (3) mark areas magnified in (4) and (5), respectively. (6–8) PB202011, thin section 19TP-1-40, F37; circled 7 and 8 in (6) mark areas magnified in (7) and (8), respectively.

Holotype

PMU-Sib.1-M/33, reposited at Uppsala University, from the Ediacaran Khamaka Formation, Nepa–Botuoba region, Yakutia, Siberia (Moczydłowska et al., Reference Moczydłowska, Vidal and Rudavskaya1993, p. 506, text-fig. 7).

Description and measurements

Vesicle large, with relatively short, slim processes evenly distributed on the vesicle. Processes thin, cylindrical or acutely conical, some with a minute basal expansion (Fig. 6.5), closely arranged but basally separated. Vesicle diameter 224–276 μm (N = 4, mean = 248 μm, SD = 22 μm); process length 11.6–18.4 μm (N = 4, mean = 14.1 μm, SD = 3.0 μm), 4.6–7.7% of vesicle diameter (N = 4, mean = 5.7%, SD = 1.4%), process basal width 1.3–3.1 μm (N = 3, mean = 2.1 μm, SD = 0.9 μm); 16–21 processes (N = 4, mean = 20, SD = 2) per 100 μm of vesicle periphery.

Material

Three illustrated specimens (Fig. 6) and one additional specimen.

Remarks

Appendisphaera tenuis was originally diagnosed as an Appendisphaera species that has relatively short processes with a possible minute basal expansion—features used to differentiate this species from A. grandis (Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993). The hollow nature of the processes was later recognized and added to the emended diagnosis of A. tenuis (Moczydłowska, Reference Moczydłowska2005), with other diagnostic features unchanged. Specimens assigned to A. tenuis in subsequent studies mostly resemble the holotype and other specimens from the type locality in Siberia in their relatively short, densely arranged, conical or cylindrical processes, with or without a small basal expansion, except that some of them (including those reported here) have larger vesicles than the Siberian specimens.

Appendisphaera tenuis shares some morphological similarities with A. clava. Both species have relatively short and densely distributed processes, which were described as cylindrical despite the slightly expanded bases (Moczydłowska, Reference Moczydłowska2005; Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a). The holotype of A. clava has a vesicle diameter of 420 μm, process length of 12 μm, which is 2.9% of vesicle diameter, process basal width of ~1 μm, and about 40 processes per 100 μm of vesicle periphery. Other A. clava specimens published together with the holotype have vesicle diameters of 250–510 μm, process length of 6–13 μm (1.7–4% of vesicle diameter), and process width and density similar to the type specimen, although basal width can be up to 3.6 μm (measured on Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 8.5). These dimensions show that A. clava has overall larger vesicles (>200 μm and up to 500 μm), proportionally shorter processes (<5% of vesicle diameter), and possibly larger process density than A. tenuis, which has a medium-sized vesicle with process length about 10% of vesicle diameter based on measurements of specimens from the type locality in Siberia. However, several specimens listed as synonyms of A. tenuis by Liu and Moczydłowska (Reference Liu and Moczydłowska2019) are similar to A. clava in measurements: one A. tenuis specimen (vesicle diameter 280 μm, process length 7.1–8.9 μm, which is 2.5–3.2% of vesicle diameter, process basal width 0.4–2.2 μm, Vorob'eva et al., Reference Vorob'eva, Sergeev and Chumakov2008), specimens originally published as Cavaspina amplitudinis (vesicle diameter 500–900 μm, process length 20–30 μm, which is 3.3–5.5% of vesicle diameter, process basal width 2–5 μm, Willman and Moczydłowska, Reference Willman and Moczydłowska2011), and two specimens originally identified as Appendisphaera sp. (vesicle diameter 550 μm, process length 10–20 μm, process basal width 2–5 μm, Ye et al., Reference Ye, Tong, An, Tian, Zhao and Zhu2015). The assignment of these specimens to A. tenuis may obscure the morphological boundary between A. clava and A. tenuis, and thus remains questionable. The same argument goes for the specimen originally identified as Ericiasphaera aff. E. addspersa by Golubkova et al. (Reference Golubkova, Raevskaya and Kuznetsov2010, pl. IV, fig. 6a, b) that was later synonymized with A. tenuis by Sergeev et al. (Reference Sergeev, Knoll and Vorob'eva2011).

In some cases, Appendisphaera tenuis can also be akin to Cavaspina basiconica, which is differentiated from A. tenuis by its less densely arranged processes with a more prominent basal expansion. In practice, however, some specimens with a moderate density of processes can fit the diagnosis of either A. tenuis or C. basiconica (e.g., Liu and Moczydłowska, Reference Liu and Moczydłowska2019, fig. 39A–D), and more quantitative criteria are needed to distinguish these two species.

Type species

Asterocapsoides sinensis Yin and Li, Reference Yin and Li1978, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Other species

Asterocapsoides fluctuensis Liu and Moczydłowska, Reference Liu and Moczydłowska2019; A. robustus Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; A. wenganensis (Chen and Liu, Reference Chen and Liu1986) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Asterocapsoides wenganensis (Chen and Liu, Reference Chen and Liu1986) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014
Figure 7

Reference Chen and Liu1986

Meghystrichosphaeridium wenganensis Chen and Liu, p. 51, pl. II, figs. 1, 3.

non Reference Yuan and Hofmann1998

Meghystrichosphaeridium wenganensis Chen and Liu; Yuan and Hofmann, p. 203, fig. 10C, D.

Reference Zhou, Brasier and Xue2001

Meghystrichosphaeridium chadianensis; Zhou et al., p. 1166, pl. 2, figs. 1–4.

non Reference Zhou, Brasier and Xue2001

Meghystrichosphaeridium chadianensis; Zhou et al., p. 1166, pl. 1, figs. 1–8; pl. 2, figs. 5–8.

Reference Zhou, Chen and Xue2002

Meghystrichosphaeridium chadianensis; Yuan et al., p. 75, fig. 103.

Reference Zhou, Yuan, Xiao, Chen and Xue2004b

Meghystrichosphaeridium chadianensis; Zhou et al., pl. V, fig. 4.

non Reference Zhou, Yuan, Xiao, Chen and Xue2004b

Meghystrichosphaeridium sp., Zhou et al., p. 354, pl. V, figs. 5, 6.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Asterocapsoides wenganensis (Chen and Liu) Xiao et al., p. 14, fig. 5.4–5.12.

Reference Shang, Liu and Moczydłowska2019

Asterocapsoides wenganensis (Chen and Liu) Xiao et al.; Shang et al., p. 11, fig. 6.

?Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2019

Asterocapsoides sp.; Ouyang et al., fig. 9C–E.

Reference Willman, Peel, Ineson, Schovsbo, Rugen and Frei2020

Asterocapsoides wenganensis; Willman et al., fig. 4c, d.

Figure 7. Asterocapsoides wenganensis (Chen and Liu, Reference Chen and Liu1986) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014. (1, 2) PB202012, thin section 21LHK-1-10, R34/4. (1) and (2) show the same area at different focal levels; red arrowheads denote large conical processes.

Neotype

The specimen illustrated by Xiao et al. (Reference Xiao, Zhou, Liu, Wang and Yuan2014, fig. 5.7) is here designated as a neotype (NIGPAS-94038-3193), reposited at NIGPAS, from Doushantuo Formation in Weng'an area, Guizhou Province, South China.

Description and measurements

Only a tangentially cut specimen was observed in thin section. The vesicle is estimated to be medium to large in size, originally spheroidal, with homomorphic, large conical processes that are likely basally in contact. Vesicle diameter of the tangential cross section is about 127 μm. The full length and basal width of processes are not captured in the thin section, but the process length is at least 42.7 μm and basal width is at least 24.2 μm based on measurements of processes partially captured in the thin section.

Material

One illustrated specimen (Fig. 7).

Remarks

Although the true vesicle diameter of the illustrated specimen cannot be determined for this specimen, which seems to be cut tangentially at the periphery of its vesicle, the specimen is probably around 200 μm in vesicle diameter. Accepting the estimated vesicle and process sizes, this specimen is most appropriately identified as Asterocapsoides wenganensis, which differs from A. robustus mainly in its fewer and proportionally larger conical processes.

One specimen identified as Asterocapsoides sp. (Ouyang et al., Reference Ouyang, Zhou, Xiao, Chen and Shao2019, fig. 9C–E) is similar to A. wenganensis based on its large spheroidal vesicle (~389 μm in diameter) with uniform, conical processes that are about 63.9 μm in length (16.4% of vesicle diameter), about 41.8 μm in basal width, and basally connected. Despite these similarities, however, its processes have slim and slender tips that are bent and twisted, apparently supporting an outer membrane. The process tips may be too fragile to be preserved in the phosphatized A. wenganensis specimens reported in Chen and Liu (Reference Chen and Liu1986) and Xiao et al. (Reference Xiao, Zhou, Liu, Wang and Yuan2014). It is also possible that the process tips may have been lost due to mechanical breakage during reworking or acid extraction of the phosphatized specimens. These possibilities need to be confirmed or rejected with thin-section observation of the phosphatized specimens. Thus, this specimen, illustrated as Asterocapsoides sp. in Ouyang et al. (Reference Ouyang, Zhou, Xiao, Chen and Shao2019), is here tentatively accepted as A. wenganensis.

A neotype is designated here for Asterocapsoides wenganensis because the repository of the original holotype (specimen illustrated in Chen and Liu, Reference Chen and Liu1986, pl. II, figs. 1, 3) from the Doushantuo Formation in Baiyan, Weng'an area, Guizhou Province, South China, cannot be located.

Type species

Bullatosphaera velata Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009.

Other species

Bullatosphaera? colliformis n. sp.

Holotype

PB202013, thin section 19CW-6-2, ZEISS Scope A1 coordinates 11×106, England Finder coordinates K30/3 (Fig. 8.1–8.6), reposited at NIGPAS, from Doushantuo Formation at the Caowan section in Zhangjiajie area, Hunan Province, South China.

Figure 8. Bullatosphaera? colliformis new species. Red arrowheads denote basally constricted spherical or hemispherical ornamentations. (1–6) Holotype, PB202013, thin section 19CW-6-2, K30/3; circled 2, 3, and 6 in (1) mark areas magnified in (2, 3, 6), respectively; circled 4 in (1) marks areas in (4, 5), which show the same area at different focal levels. (7–10, 13) PB202014, thin section 19CW-6-12, L31/4. (7, 8) Show the same area at different focal levels; circled 9 in (7) marks area magnified in (9); circled 10 and 13 in (8) mark areas magnified in (10) and (13), respectively. (11, 12, 14) PB202015, thin section 19CW-9-7, O35/4; circled 12 and 14 in (11) mark areas magnified in (12) and (14), respectively. Scale bars in (3) and (6) also apply to (2, 4, 5); scale bars in (9) and (12) also apply to (10, 13, 14).

Figure 9. Sketch of Bullatosphaera? colliformis new species.

Diagnosis

Vesicle spheroidal, small to medium-sized, covered by closely packed, small, spherical or hemispherical structures that are analogous to processes. The spherical or hemispherical structures are uniform in size, hollow, and attached to the vesicle surface by a thin, short, cylindrical, neck-like basal stem, but they do not communicate with the vesicle interior.

Description and measurements

Vesicle diameter 94 μm in holotype, 81 and 88 μm in the two other specimens. Spherical or hemispherical structures 8.1 μm wide and 5.5 μm high in holotype, whereas those structures in the two other specimens are 7.7 and 9.9 μm wide and 6.5 and 8.1 μm high, respectively, with a density of 11–14 such structures (13 in holotype) per 100 μm of vesicle periphery.

Etymology

From Latin collum, neck, with reference to the neck-like stem that connects the spherical processes to the vesicle wall.

Material

Three illustrated specimens (Fig. 8).

Remarks

The three illustrated specimens are characterized by the uniform spherical or hemispherical structures surrounding their vesicles, which are distinctive structures of Bullatosphaera. The lack of a second vesicle wall that surrounds the ornamentations, which is a diagnostic feature of Bullatosphaera, could be a result of degradation and diagenesis, as is possibly the case for Bullatosphaera sp. that was illustrated by Xiao et al. (Reference Xiao, Zhou, Liu, Wang and Yuan2014, p. 16, fig. 6.7, 6.8). The basally constricted stem differentiates B.? colliformis n. sp. from B. velata Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009, and Bullatosphaera sp. (Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014). However, this feature is not included in the diagnosis for the genus Bullatosphaera, therefore the placement of this new species in the genus Bullatosphaera remains provisional.

Type species

Cavaspina acuminata (Kolosova, Reference Kolosova1991) Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993.

Other species

Cavaspina basiconica Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993; C. conica Liu and Moczydłowska, Reference Liu and Moczydłowska2019; C. tiwariae Xiao in Xiao et al., Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022; C. uria (Nagovitsin and Faizullin in Nagovitsin et al., Reference Nagovitsin, Faizullin and Yakshin2004) Nagovitsin and Moczydłowska in Moczydłowska and Nagovitsin, Reference Moczydłowska and Nagovitsin2012.

Cavaspina acuminata (Kolosova, Reference Kolosova1991) Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993
 Figure 10.1

Reference Yin, Xue and Yuan1990

3-D preserved spinose microsphere; Yin et al., pl. II.A–B.

Reference Moczydłowska, Vidal and Rudavskaya1993

Cavaspina acuminata (Kolosova) Moczydłowska, Vidal, and Rudavskaya, p. 509, text-fig. 10A–B.

Reference Zhang, Yin, Xiao and Knoll1998

Goniosphaeridium acuminatun (Kolosova); Zhang et al., p. 28, fig. 8.3.

Reference Yuan, Xiao, Yin, Knoll, Zhou and Mu2002

Goniosphaeridium acuminatun (Kolosova) Zhang et al.; Yuan et al., p. 74, fig. 99.

Reference Nagovitsin, Faizullin and Yakshin2004

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Nagovitsin et al., p. 12, pl. II, figs. 7, 8.

Reference Moczydłowska2005

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Moczydłowska, p. 298, fig. 6A, B.

Reference Veis, Vorob'eva and Golubkova2006

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Veis et al., pl. I, figs. 5, 6, pl. II, fig. 1.

Reference Willman and Moczydłowska2008

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Willman and Moczydłowska, p. 522, fig. 9C.

Reference Vorob'eva, Sergeev and Knoll2009

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Vorob'eva et al., p. 177, fig. 7.11.

Reference Willman and Moczydłowska2011

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Willman and Moczydłowska, p. 24, pl. II, fig. 3.

Reference Moczydłowska and Nagovitsin2012

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Moczydłowska and Nagovitsin, p. 13, fig. 4C, E, F.

Reference Zeng, Chen, Li, Zhou, Zhang and Peng2013

Tanarium sp.; Zeng et al., fig. 3.5.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Xiao et al., p. 16, fig. 7.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Liu et al., p. 44, fig. 27.1, 27.2.

Reference Shukla and Tiwari2014

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Shukla and Tiwari, p. 216, fig. 5C, D.

Reference Prasad and Asher2016

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Prasad and Asher, p. 46, pl. IV, figs. 5, 6.

Reference Nie, Liu and Dong2017

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Nie et al., p. 374, fig. 5.1–5.4.

Reference Liu and Moczydłowska2019

Cavaspina acuminata (Kolosova, Reference Kolosova1991) Moczydłowska et al. Reference Moczydłowska, Vidal and Rudavskaya1993; Liu and Moczydłowska, p. 76, fig. 38.

Reference Shang, Liu and Moczydłowska2019

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Shang et al., p. 19, fig. 8A–D.

Reference Shang, Liu and Liu2020

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Shang and Liu, p. 157, fig. 5D–H.

Reference Grazhdankin, Nagovitsin, Golubkova, Karlova, Kochnev, Rogov and Marusin2020

Cavaspina acuminata; Grazhdankin et al., fig. 4H.

Reference Willman, Peel, Ineson, Schovsbo, Rugen and Frei2020

Cavaspina acuminata; Willman et al., fig. 4a, b.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Ouyang et al., fig. 13A.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Shi et al., fig. 7C–E (illustrated in Fig. 11.1, one of the two specimens described here).

?Reference Ye, Li, Tong, An, Hu and Xiao2022

Cavaspina acuminata (Kolosova) Moczydłowska et al.; Ye et al., fig. 13A, B.

Reference Golubkova2023

Cavaspina acuminata (Kolosova) emend. Moczydłowska; Golubkova, pl. 7, fig. 5.

Figure 10. (1) Cavaspina acuminata (Kolosova, Reference Kolosova1991) Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, PB202016, thin section 21DC-3-1, Q30/4. (2) Cavaspina basiconica Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, PB202017, thin section 21DC-5-4, M40/1. (3, 4) Cavaspina uria (Nagovitsin and Faizullin in Nagovitsin et al., Reference Nagovitsin, Faizullin and Yakshin2004) Nagovitsin and Moczydłowska in Moczydłowska and Nagovitsin, Reference Moczydłowska and Nagovitsin2012, thin section 21DC-5-4; red arrowheads in (1–4) denote conical processes; (3) PB202018, G41/1; (4) PB202019, E45/4. (5–7) Eotylotopalla sp. PB202025, thin section 19CW-6-15, O41/1, showing the same area at different focal levels. Scale bars in (5) and (7) also apply to (6).

Figure 11. (1–4, 7, 8) Eotylotopalla dactylos Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998. (1) PB202020, thin section 19TP-1-13; (2) PB202021 (left) and PB202022 (right), thin section 21DC-2-38, Q48; (3, 4) PB202023, thin section 14HA-115-1, D47/3, showing the same area at different focal levels; (7, 8) PB202024, thin section 21DC-5-3, Q30/3, showing the same area at different focal levels. (5, 6, 9–12) Eotylotopalla cf. E. dactylos Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998, PB202026, thin section 21DC-2-12, O21/4. (5, 6) The same area at different focal levels; (9–12) magnified views of the processes denoted by circled 9–12 in (6) under cross-polarized light; red arrowheads denote the angular transition from the side wall of the processes to the distal end.

Holotype

YIGS Nr 87-123, reposited at the Geological Museum of Yakutian Institute of Geologic Sciences (present Diamond and Precious Metal Geology Institute, Siberian Branch, Russian Academy of Sciences), from the Ediacaran Torgo Formation, Berezovo area, eastern Siberia (Kolosova, Reference Kolosova1991, p. 57, fig. 4.1).

Description and measurements

Vesicle small, spheroidal, bearing sparsely and evenly distributed, acutely conical processes. The illustrated specimen has a vesicle diameter of about 84 μm, process length about 6.3 μm (7.5% of vesicle diameter), and process basal width about 1.5 μm (process length to basal width ratio ~4.2), with about 23 processes per 100 μm of vesicle periphery. The other specimen has a vesicle diameter of about 41 μm, process length about 5.7 μm (13.8% of vesicle diameter), and process basal width about 1.8 μm (process length to basal width ratio ~3.2), with 12 processes per 100 μm of vesicle periphery.

Material

One illustrated specimen (Fig. 10.1) and one additional specimen.

Remarks

Being one of the most widely distributed Ediacaran acanthomorphic species, Cavaspina acuminata is characterized by its relatively sparsely distributed, short, and acutely conical processes. Both specimens described here, although not well preserved and together covering a large variation in size and process density, meet the diagnosis of C. acuminata, best demonstrated by the process basal width (<2 μm) and process length to basal width ratio (>3).

One Cavaspina acuminata specimen reported by Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 13A, B) appears to have terminally branching processes and, if confirmed, would be better identified as Variomargosphaeridium gracile Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014 (see Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021, fig. 22A). Therefore, the identification of the specimen illustrated in Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022) as C. acuminata is questioned here, pending re-examination of the specimen to confirm or reject the terminal branching structures.

Holotype

PMU-Sib.1-Y/55/2, reposited at Uppsala University, from the Ediacaran Khamaka Formation, Nepa–Botuoba region, Yakutia, Siberia (Moczydłowska et al., Reference Moczydłowska, Vidal and Rudavskaya1993, p. 510, text-fig. 11A, B, D).

Description and measurements

Vesicle small to medium-sized, spheroidal, bearing a small to moderate number of evenly distributed processes. Processes conical, with a small but clearly defined basal expansion that is deflated. The illustrated specimen has a vesicle diameter of about 138 μm, process length about 12.3 μm (8.9% of vesicle diameter), and process basal width about 10.2 μm (process length to basal width ratio ~1.2), with about one process per 100 μm of vesicle periphery. The other specimen has a vesicle diameter of about 94 μm, process length about 12.5 μm (13.2% of vesicle diameter), and process basal width about 3.8 μm (process length to basal width ratio ~3.3), with 17 processes per 100 μm of vesicle periphery.

Material

One illustrated specimen (Fig. 10.2) and one additional specimen illustrated in Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017, fig. 8A–C).

Remarks

Both specimens described here are poorly preserved, thus the seemingly ciliate apical part of the processes are likely a result of diagenetic contraction of originally acutely tapering processes. Although resembling Cavaspina acuminata in morphometrics of process shape, the two C. basiconica specimens described here can be readily recognized by their processes with a deflated basal expansion. This feature also distinguishes them from C. uria, whose processes have a broad base that is not deflated.

Holotype

Copy 7 of preparation PN 8/17(2)-1, No. 673 CSGM, reposited at Central Siberian Geological Museum of the United Institute of Geology, Geophysics and Mineralogy (present Trofimuk Institute of Petroleum–Gas Geology and Geophysics), Siberian Branch, Russian Academy of Sciences, from the Ediacaran Ura Formation, Patom Uplift, eastern Siberia (Nagovitsin et al., Reference Nagovitsin, Faizullin and Yakshin2004, pl. II, fig. 1).

Description and measurements

Vesicle spheroidal, small, bearing evenly distributed conical processes. Process uniform, with a triangular outline in thin-sectional view. Vesicle diameter 41–99 μm (N = 6, mean = 60 μm, SD = 20 μm). Based on measurements of four better preserved specimens among the six available ones, process length is 5.2–7.2 μm (N = 4, mean = 6.0 μm, SD = 1.0 μm), representing 8.8–13.4% of vesicle diameter (N = 4, mean = 10.8%, SD = 2.0%), process basal width 3.3–4.6 μm (N = 4, mean = 3.8 μm, SD = 0.6 μm), process length to basal width ratio 1.5–1.8 (N = 4, mean = 1.6, SD = 0.1), and 11–17 processes (N = 4, mean = 15, SD = 3) per 100 μm of vesicle periphery.

Material

Two illustrated specimens (Fig. 10.3, 10.4), two specimens illustrated in Shi et al. (Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 7J, M), and two additional specimens.

Remarks

With conical processes whose length accounts for about 10% of vesicle diameter, Cavaspina uria is somewhat similar to Asterocapsoides robustus in process shape. However, most published specimens of A. robustus are much larger in vesicle size. The specimen identified as A. robustus from the Doushantuo Formation in Zhangcunping area, South China (Ouyang et al., Reference Ouyang, Zhou, Xiao, Chen and Shao2019, fig. 9A, B) has evenly distributed conical processes, with vesicle diameter of about 70 μm, process length of 7.0 μm, and process basal width of 4.0 μm, which are comparable to those of C. uria, especially the holotype (vesicle diameter 80 μm, process length 7–8 μm, process basal width 4–5 μm), but differ significantly from typical A. robustus specimens. Thus, we reassign this specimen to C. uria.

Type species

Eotylotopalla delicata Yin, Reference Yin1987.

Other species

Eotylotopalla apophysa (Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009) Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022; E. dactylos Zhang et al., Reference Zhang, Yin, Xiao and Knoll1998; E. quadrata Liu and Moczydłowska, Reference Liu and Moczydłowska2019; E. strobilata (Faizullin, Reference Faizullin1998) Sergeev et al., Reference Sergeev, Knoll and Vorob'eva2011 (E. minorosphaera Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009); E. inflata n. sp.

Remarks

Eotylotopalla now accommodates most of the Ediacaran acanthomorphs with inflated processes that are terminally rounded or truncated (i.e., lacking a pointed process tip). Processes of Eotylotopalla can be cylindrical (E. dactylos), hemispherical (E. apophysa, E. delicata, E. strobilata, differentiated mainly by their proportional process size relative to vesicle diameter), cuboidal (E. quadrata), or distally inflated (E. inflata n. sp.). With the addition of E. inflata n. sp., Eotylotopalla can also have biform processes (although different from the basally inflated biform processes of Mengeosphaera). Despite these morphological variations, Eotylotopalla remains a very distinctive genus characterized by its distally expanded, rounded, flat or truncated processes.

Holotype

Specimen illustrated in Zhang et al. (Reference Zhang, Yin, Xiao and Knoll1998, fig. 7.8), thin section #XDV-29m-6, Leitz coordinates 48×123, reposited at NIGPAS, from the Ediacaran Doushantuo Formation at Xiaofenghe in the Yangtze Gorges area, Hubei Province, South China.

Description and measurements

Vesicle small and spheroidal, with uniform, near evenly distributed processes that can be either basally connected or separated. Processes are cylindrical or taper slightly toward the distal end, with a rounded or blunt terminal end. Vesicle diameter 39–60 μm (N = 5, mean = 49 μm, SD = 7 μm), with 5–11 processes per 100 μm of vesicle periphery (N = 3, mean = 7 μm, SD = 4); process lengths 6.4–10.2 μm (N = 5, mean = 7.7 μm, SD = 0.7 μm) or 13.2–26.0% of vesicle diameter (N = 5, mean = 16.4%, SD = 5.4%), and process basal width 7.1–13.2 μm (N = 5, mean = 9.9 μm, SD = 3.0 μm) or 14.9–24.4% of vesicle diameter (N = 5, mean = 20.3%, SD = 4.0%).

Material

Five illustrated specimens (Fig. 11.1–11.4, 11.7, 11.8), including one (Fig. 11.7, 11.8) previously illustrated in Shi et al. (Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 8A) and another (Fig. 11.3, 11.4) previously assigned to “indeterminate acanthomorphs” by Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017, table 1).

Remarks

Compared with other Eotylotopalla species with very limited intraspecific morphological variation (E. delicata, E. inflata n. sp., E. quadrata, E. strobilata), processes of E. dactylos are relatively more variable in morphology, which can be cylindrical (digitate) or conical, basally separate, connected, or joined, with moderate basal or terminal expansions. Measurements of previously published E. dactylos illustrations (as listed in synonym list, Fig. 12) show that most published specimens have vesicle diameters of 30–105 μm, 5–31 μm in process length (10–30% of vesicle diameter), 6–26 μm in process basal width (11–28% of vesicle diameter), with 3–12 processes per 100 μm of vesicle periphery. Specimens described here fit the diagnostic features of E. dactylos both qualitatively and quantitatively.

Figure 12. Morphological comparisons between Eotylotopalla specimens described here, published Eotylotopalla dactylos, and specimens identified as Eotylotopalla sp. by Liu et al. (Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) and by Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022) but reassigned to Eotylotopalla dactylos in this study. Symbols with black outline represent specimens described in this study. Note that two of the three specimens published as Eotylotopalla sp. (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 31.10, 31.11, and Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 23H–J) are very poorly preserved thus their process density (number of processes per 100 μm of vesicle periphery) is unmeasurable.

Three poorly preserved specimens previously published by Liu et al. (Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 31.10–31.13) and Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 23H–J) have been identified as Eotylotopalla sp. despite their similarities to E. dactylos acknowledged by the original authors. These specimens were considered different from E. dactylos in their more sparsely distributed processes (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022). However, if we quantitively assess previously published specimens of E. dactylos, there is a wide range of process density (Fig. 12). Several E. dactylos specimens accepted by various authors also have sparsely distributed processes (e.g., Zhou et al., Reference Zhou, Xie, McFadden, Xiao and Yuan2007, fig. 4F), with 2–3 processes per 100 μm of vesicle periphery, which is not much different from the three specimens of Eotylotopalla sp. cited above (Fig. 12). Thus, considering the intraspecific variation in process density, we reassign these Eotylotopalla sp. specimens to E. dactylos.

Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022) transferred Timanisphaera apophysa Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009, to Eotylotopalla and synonymized it with E. grandis Tang et al., Reference Tang, Pang, Xiao, Yuan, Ou and Wan2013, thus forming a new combination E. apophysa (Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009) Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022, characterized by its large vesicles with sparse but proportionally large, hemispherical processes. One specimen assigned to T. apophysa (Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 23G) is about 170 μm in vesicle diameter and notably smaller than the holotype measurements mentioned in the original diagnosis (vesicle size 265–450 μm in diameter, process 70–110 μm in length and 50–90 μm in width). However, considering that Ye et al.'s (Reference Ye, Li, Tong, An, Hu and Xiao2022) specimen is silicified and was examined in a petrographic thin section, its vesicle diameter measurement is likely a minimum estimate because the specimen may be tangentially cut. Similarly, a specimen of E. dactylos illustrated by Ouyang et al. (Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021, fig. 14J), characterized by an even smaller vesicle (~59 μm in diameter) and a small number of large processes (~22 μm in length or 37% of vesicle diameter) also may be assigned to E. apophysa. Thus, the specimen of E. dactylos published in Ouyang et al. (Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021) is questionably included in the synonym list.

Description and measurements

Vesicle small and spheroidal, with basally separated processes densely distributed on the vesicle. Processes are uniform and truncated conical in shape. The side walls of processes are straight. Vesicle diameter about 64 μm, with about 7 processes per 100 μm of vesicle periphery; processes length 6.9–10.9 μm (with an average of 8.9 μm measured on four processes) or 10.7–17.0% of vesicle diameter (with an average of 13.8%), process basal width 7.6–12.5 μm (with an average of 10.7 μm measured on four processes), process terminal width 3.7–6.4 μm (with an average of 5.0 μm measured on four processes).

Material

One illustrated specimen (Fig. 11.5, 11.6, 11.9–11.12).

Remarks

The illustrated specimen is distinct in its sharply terminated processes but is otherwise comparable to Eotylotopalla. Examination under polarized light (Fig. 11.9–11.12) shows that the process terminal truncation is not a taphonomic artifact (e.g., recrystallization). Truncated terminations are common in previously reported E. dactylos specimens, but the transition from the side wall to distal end of the processes in these specimens is smooth and gradual, as opposed to the angular transition observed in the illustrated specimen (red arrowheads in Fig. 11.9–11.12). We cannot rule out the possibility that the angular transition is due to mechanical breakage of the processes, however the uniform length of the processes is remarkable for broken processes. Abrasion by tumbling at a constant rate may result in similar process lengths but is unlikely to form flat terminations as observed. Thus, this specimen is currently placed in an open nomenclature related to E. dactylos.

Holotype

PB202027, thin section 19TP-1-38, ZEISS Scope A1 coordinates 14×105, England Finder coordinates N30/3 (Fig. 13), reposited at NIGPAS, from Doushantuo Formation at the Tianping section in Zhangjiajie area, Hunan Province, South China.

Figure 13. Eotylotopalla inflata new species. (1–4) Holotype, PB202027, thin section 19TP-1-38, N30/3, showing the same area at different focal levels.

Diagnosis

A species of Eotylotopalla with terminally inflated processes that have a slightly expanded base, a neck, and a bulbous distal end, with an overall shape resembling a button mushroom.

Description and measurements

Vesicle small, spheroidal or ovoidal, with evenly distributed, basally connected or separated processes. Processes hollow and open to vesicle cavity, homomorphic, with a widened base, and an inflated bulbous termination, and a neck- or waist-like structure in between. Vesicle diameter about 64 μm, about 12 processes per 100 μm of vesicle periphery; processes length 8.7–11.5 μm with an average of 10.4 μm measured on eight processes or 13.6–18.0% of vesicle diameter with an average of 16.1%, process basal width 5.7–8.5 μm with an average value of 7.1 μm measured on eight processes, maximal width of inflated process termination 4.4–6.4 μm with an average value of 5.5 μm measured on eight processes, minimal width of process waist 2.5–3.2 μm with an average value of 2.8 μm measured on seven processes.

Etymology

From Latin inflatus, inflated, with reference to the inflated terminal end of the processes.

Material

A single well-preserved specimen (the holotype, Fig. 13).

Remarks

The illustrated specimen is distinctive in its basally widened and terminally swollen processes that resemble a button mushroom. This distinctive morphology is observed in more than 20 processes in the specimen, supporting the repeatability and arguing against a taphonomic origin of this diagnostic feature. Somewhat similar process morphology has been described in Stellarossica ampla Vorob'eva and Sergeev, Reference Vorob'eva and Sergeev2018, from the Ura Formation in Siberia and two species of Keltmia (K. cornifera Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009, and K. irregularia Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009) from the Vychegda Formation in East European Platform. However, these latter species can be distinguished from Eotylotopalla inflata n. sp. by their much larger vesicle, notably fewer processes, much larger proportional lengths of processes, and most importantly, the terminal end of their processes is not as strongly inflated as in the new species where the maximum width of process termination is almost double the minimum width of process waist. There are other acanthomorphs with significantly expanded process bases and terminations, including all Urasphaera species and Weissiella brevis Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014. However, Urasphaera species and Weissiella brevis are characterized by processes with flat or truncated terminations, thus different from the bulbous terminations reported here.

Papillomembrana Spjeldnaes, Reference Spjeldnaes1963, emend. Vidal, Reference Vidal1990, is another genus characterized by processes with a bulbous terminal end, but it is diagnosed as an acanthomorph with medium to large vesicle size (Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014), and the processes of both P. boletiformis Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014, and P. compta Spjeldnaes, Reference Spjeldnaes1963, emend. Vidal, Reference Vidal1990, lack a well-defined basal expansion and have a basal width smaller than the terminal width. The illustrated specimen is small in vesicle size, and its processes are basally widened, thus different from known Papillomembrana species. To assign the illustrated specimen to Papillomembrana would require an emendation to this genus and would significantly increase the morphological perimeter of this genus. Considering that the small vesicle with densely distributed, distally rounded processes of the specimen described here (Fig. 13) fits the genus diagnosis of Eotylotopalla, and that it is different from other existing species of Eotylotopalla species in its basally and distally expanded processes, we establish a new species of Eotylotopalla even though there is only one available specimen.

Description and measurements

Small spheroidal vesicle with large, hollow, heteromorphic processes that can be either cylindrical or bulbous. Cylindrical-shaped processes have rounded or blunt terminal ends. Some processes show a notable constriction in the basal or middle part, resulting in mushroom- or dumbbell-like morphology. The processes vary in basal width and the presence of a constriction but are more consistent in length and the rounded terminal end. Vesicle diameter about 73 μm; process length 21.4–30.5 μm (measured on seven processes, with an average of 25.1 μm and a standard deviation of 3.0 μm), process basal width 12.6–30.5 μm (on seven processes, with an average of 20.2 μm and a standard deviation of 6.0 μm), process terminal width 14.7–27.4 μm (on five processes, with an average of 19.3 μm and a standard deviation of 4.6 μm), process constriction width 6.2–19.1 μm (on four processes, with an average of 10.1 μm and a standard deviation of 5.2 μm). About seven processes are present around half of the vesicle periphery, equivalent to three processes per 100 μm of vesicle periphery.

Material

One specimen illustrated in Figure 10.5–10.7.

Remarks

The specimen described here is similar to Eotylotopalla dactylos in vesicle size (Fig. 12) and the presence of cylindrical processes with rounded or blunt terminal ends. It is also similar to E. apophysa and E. delicata in the presence of bulbous-shaped processes, and to E. inflata n. sp. in the presence of mushroom-like processes. However, it is distinct in its remarkably heteromorphic processes, which can be 12.6–30.5 μm in basal width and can be cylindrical or mushroom-like due to the presence of a constriction (Fig. 10.7). Variation in process size and shape has been reported for E. dactylos (e.g., Zhou et al., Reference Zhou, Xie, McFadden, Xiao and Yuan2007, fig. 4F; Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 31.4), but the amount of morphological variation observed in the single specimen illustrated here is remarkable. On the other hand, the irregular morphology of the only available specimen dissuades us from establishing a new species. Therefore, although this specimen probably represents a new form, it is temporarily placed in open nomenclature.

Type species

Hocosphaeridium scaberfacium Zang in Zang and Walter, Reference Zang and Walter1992, emend. Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a.

Other species

Hocosphaeridium anozos (Willman in Willman and Moczydłowska, Reference Willman and Moczydłowska2008) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; H. dilatatum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a.

Hocosphaeridium anozos (Willman in Willman and Moczydłowska, Reference Willman and Moczydłowska2008), Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014
 Figure 14

Reference Zang and Walter1992

Hocosphaeridium scaberfacium Zang in Zang and Walter, fig. 45 G (not 45A–F).

Reference Grey2005

Tanarium irregulare? Moczydłowska, Vidal, and Rudavskaya; Grey, p. 309, fig. 225.

Reference Willman and Moczydłowska2008

Tanarium anozos Willman in Willman and Moczydłowska, p. 526, fig. 13A–F.

Reference Yin, Liu, Awramik, Chen, Tang, Gao, Wang and Riedman2011

Tanarium anozos Willman; C. Yin et al., fig. 6d.

Reference Liu, Yin, Chen, Tang and Gao2012

Tanarium anozos Willman and Moczydłowska; Liu et al., fig. 3A–C.

Reference Liu, Yin, Chen, Tang and Gao2013

Tanarium anozos; Liu et al., fig. 11B.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Hocosphaeridium anozos (Willman in Willman and Moczydłowska) Xiao et al., p. 28, fig. 16.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Hocosphaeridium anozos (Willman in Willman and Moczydłowska) Xiao et al.; Liu et al., p. 75, figs. 37, 38, 39.1.

Reference Liu, Chen, Zhu, Li, Yin and Shang2014b

Hocosphaeridium anozos; Liu et al., fig. 8A, B.

non Reference Prasad and Asher2016

Tanarium anozos Willman in Willman and Moczydłowska; Prasad and Asher, p. 54, pl. VII, figs. 6, 7.

Reference Hawkins, Xiao, Jiang, Wang and Shi2017

Hocosphaeridium anozos; Hawkins et al., fig. 7E, F.

Reference Liu and Moczydłowska2019

Hocosphaeridium anozos (Willman in Willman and Moczydłowska) Xiao et al.; Liu and Moczydłowska, p. 113, fig. 60.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Hocosphaeridium anozos (Willman in Willman and Moczydłowska) Xiao et al.; Shi et al., fig. 8G–K (two of the 20 specimens described here).

Figure 14. Hocosphaeridium anozos (Willman in Willman and Moczydłowska, Reference Willman and Moczydłowska2008) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; red arrowheads denote hooked process terminations. (1–5) PB202028, thin section 21DC-2-20, R20/2; circled 2–5 in (1) mark areas magnified in (2–5), respectively; scale bars in (3) and (5) also apply to (2) and (4). (6–8) PB202029, thin section 21DC-2-20, P18/2; circled 7 and 8 in (6) mark areas magnified in (7) and (8), respectively; scale bar in (8) also applies to (7). (9–11) PB202030, thin section 21DC-2-20, R21; circled 10 and 11 in (9) mark areas magnified in (10) and (11), respectively. (12–14) PB202031, thin section 21DC-2-20, O18/3; circled 13 and 14 in (12) mark areas magnified in (13) and (14), respectively.

Holotype

CPC 39635, reposited at Commonwealth Palaeontological Collection (CPC) at Geoscience Australia, Canberra, from the Ediacaran Tanana Formation of the Giles 1 drillhole in Officer Basin, South Australia.

Description and measurements

Most vesicles are deformed to various degrees, but were originally spheroidal in shape, and measurements can be taken on relatively well-preserved specimens. Processes evenly distributed on the vesicle surface, cylindrical or slightly tapering toward a distal end that is hooked or recurved. Vesicle diameter 88–227 μm (N = 13, mean = 143 μm, SD = 39 μm); process length 20.8–54.8 μm (N = 19, mean = 33.4 μm, SD = 7.4 μm), 14.0–34.9% of vesicle diameter (N = 13, mean = 24.6%, SD = 7.3%); process width (diameter) 1.0–2.4 μm (N = 20, mean = 1.9 μm, SD = 0.3 μm); process density unmeasurable due to the small number of processes with a well-preserved base.

Material

Four illustrated specimens (Fig. 14) and 16 additional specimens (including the one illustrated by Shi et al., Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 8J, K).

Remarks

These specimens are poorly preserved in general, but all bear a characteristically hooked tip in the terminal end of their thin, cylindrical processes. They can be differentiated from Hocosphaeridium scaberfacium by their cylindrical processes, and from H. dilatatum by their low process density and the lack of a process basal expansion in most specimens. In some processes, an obtusely conical or even slightly inflated base is observed (e.g., process on the right in Fig. 14.13). However, such structures only appear in deformed specimens, and thus are likely to be taphonomic in origin. Only specimens with well-defined process terminal ends are accepted as Hocosphaeridium. There are far more acanthomorphic specimens that resemble H. anozos in overall size and morphology but are taxonomically unidentifiable because the terminal ends of their processes are not captured in thin sections. Therefore, the reported abundance of H. anozos in this study is likely an underestimate.

Hocosphaeridium scaberfacium Zang in Zang and Walter, Reference Zang and Walter1992, emend. Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a
 Figure 15

Reference Zang and Walter1992

Hocosphaeridium scaberfacium Zang in Zang and Walter, p. 61, fig. 45A–F (not 45G).

Reference Yuan and Hofmann1998

Hocosphaeridium scaberfacium Zang and Walter; Yuan and Hofmann, p. 203, fig. 10A, B.

Reference Zhang, Yin, Xiao and Knoll1998

Goniosphaeridium conoideum (Kolosova) Zhang et al., p. 32, fig. 9.1–9.4.

Reference Yuan, Xiao, Yin, Knoll, Zhou and Mu2002

Goniosphaeridium conoideum (Kolosova) Zhang et al.; Yuan et al., p. 74, fig. 100.

Reference Grey2005

Tanarium conoideum Kolosova; emend. Moczydłowska et al.; Grey, p. 299, figs. 212, 213.

Reference Willman, Moczydłowska and Grey2006

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Willman et al., p. 32, pl. VI, figs. 1, 2.

Reference Willman and Moczydłowska2008

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Willman and Moczydłowska, p. 526, fig. 12C.

Reference Golubkova, Raevskaya and Kuznetsov2010

Tanarium conoideum (Kolosova) emend. Moczydłowska et al.; Golubkova et al., pl. III, fig. 7, pl. IV, fig. 2.

Reference Moczydłowska and Nagovitsin2012

Tanarium anozos Willman in Willman and Moczydłowska; Moczydłowska and Nagovitsin, p. 18, fig. 8A–C.

Reference Liu, Yin, Chen, Tang and Gao2012

Tanarium anozos Kolosova; Liu et al., fig. 3D–F.

Reference Liu, Yin, Chen, Tang and Gao2013

Tanarium conoideum; Liu et al., fig. 11A.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Hocosphaeridium scaberfacium Zang in Zang and Walter; Xiao et al., p. 27.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Hocosphaeridium scaberfacium Zang in Zang and Walter, emend. Liu et al., p. 78, figs. 39.3, 41, 42.

Reference Liu, Chen, Zhu, Li, Yin and Shang2014b

Hocosphaeridium scaberfacium; Liu et al., fig. 8C.

Reference Liu, Qi, Fan, Guo and Pei2021

Hocosphaeridium scaberfacium; Liu et al., fig. 6.3, 6.4.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Hocosphaeridium scaberfacium Zang in Zang and Walter; Shi et al., fig. 8L, M (one of the specimens described here).

Reference Ye, Li, Tong, An, Hu and Xiao2022

Hocosphaeridium scaberfacium Zang in Zang and Walter, Reference Zang and Walter1992, emend. Liu et al.; Ye et al., p. 41, fig. 26H–J.

Figure 15. Hocosphaeridium scaberfacium Zang in Zang and Walter, Reference Zang and Walter1992, emend. Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; red arrowheads denote hooked process terminations. (1–3) PB202032, thin section 19HP-1-28, Q33; circled 2 and 3 in (1) mark the same area magnified in (2) and (3), respectively, at different focal levels to show different processes. (4–6) PB202033, thin section 19TP-1-40, K44; circled 5 and 6 in (4) mark areas magnified in (5) and (6), respectively. (7, 8) PB202034, thin section 19CW-6-15, N40/4; circled 8 in (7) marks the area magnified in (8). (9) PB202035, thin section 19SDP-7-3, G41/1. (10–12) PB202036, thin section 21DC-2-20, P18; circled 11 and 12 in (10) mark areas magnified in (11) and (12), respectively.

Holotype

CPC 27765, thin section 87ZW01-8, reposited at Commonwealth Palaeontological Collection (CPC) at Geoscience Australia, Canberra, from the Ediacaran Pertatataka Formation of the Rodinga 4 drill core in Amadeus Basin, Northern Territory, Australia.

Description and measurements

Vesicles mostly medium-sized, compressed to different degrees but were originally spheroidal based on several less severely compressed specimens (Fig. 15.1–15.3, 15.4–15.7). Vesicles bear a varying number of conical and distally tapering processes with a relatively wide base and a hooked or recurved tip. Vesicle diameter 114–212 μm (N = 6, mean = 170 μm, SD = 38 μm); process length 36.3–58.3 μm (N = 9, mean = 45.2 μm, SD = 7.9 μm), 18.6–39.5% of vesicle diameter (N = 6, mean = 26.5%, SD = 8.4%); process basal width 6.8–22.8 μm (N = 9, mean = 12.9 μm, SD = 4.8 μm). As measured on one specimen (Fig. 15.1–15.3), there are about two processes per 100 μm of vesicle periphery.

Material

Five illustrated specimens (Fig. 15) and four additional specimens (including the one illustrated by Shi et al., Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 8L, M).

Remarks

Despite the modest preservation quality, the conical processes with a hooked termination and the lack of a basal expansion structure are clearly discernable in our specimens. These features allow the taxonomical identification to Hocosphaeridium scaberfacium. Although the distal part of processes is recurved for at least 180° and up to 270° (e.g., Fig. 15.2, 15.3), the basal part of the processes remains straight, indicating that the hooked structures are biological in origin. As in the case of H. anozos, there are some specimens in our collection that could be H. scaberfacium but are currently placed in the category of unidentified acanthomorphs because the distal part of the processes is not captured in the thin sections.

Type species

Knollisphaeridium maximum (Yin, Reference Yin1987) Willman and Moczydłowska, Reference Willman and Moczydłowska2008, emend. Liu and Moczydłowska, Reference Liu and Moczydłowska2019.

Other species

Knollisphaeridium? bifurcatum Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; K. coniformum Liu and Moczydłowska, Reference Liu and Moczydłowska2019; K. denticulatum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; K. gravestockii (Grey, Reference Grey2005) Willman and Moczydłowska, Reference Willman and Moczydłowska2008; K. longilatum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; K. obtusum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; K. parvum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; K. triangulum (Zang in Zang and Walter, Reference Zang and Walter1992) Willman and Moczydłowska, Reference Willman and Moczydłowska2008, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Knollisphaeridium maximum (Yin, Reference Yin1987), Willman and Moczydłowska, Reference Willman and Moczydłowska2008, emend. Liu and Moczydłowska, Reference Liu and Moczydłowska2019
 Figure 16

Reference Yin1987

Baltisphaeridium maximum Yin, p. 439, pl. 14, figs. 14, 15.

Reference Knoll and Walter1992

Echinosphaeridium maximum (Yin) Knoll, p. 765, pl. 5, figs. 5, 6.

Reference Tiwari and Knoll1994

Echinosphaeridium maximum (Yin) Knoll; Tiwari and Knoll, p. 196, pl. I, fig. 3.

Reference Zhang, Yin, Xiao and Knoll1998

Echinosphaeridium maximum (Yin) Knoll; Zhang et al., p. 26, figs. 6.9, 6.10, 7.1, 7.2.

non Reference Zhang, Yin, Xiao and Knoll1998

Echinosphaeridium maximum (Yin) Knoll; Zhang et al., p. 26, fig. 6.7, 6.8.

non Reference Yuan and Hofmann1998

Echinosphaeridium maximum (Yin) Knoll; Yuan and Hofmann, p. 202, fig. 8A–D.

non Reference Yin1999

Echinosphaeridium maximum (Yin) Knoll; Yin, pl. 4, figs., 4, 5.

non Reference Xiao and Knoll1999

Echinosphaeridium maximum; Xiao and Knoll, fig. 11A–C.

non Reference Zhou, Brasier and Xue2001

Echinosphaeridium maximum; Zhou et al., pl. 3, figs. 1, 2.

Reference Zhou, Yuan, Xiao, Chen and Xue2004b

Echinosphaeridium maximum (Yin) Knoll; Zhou et al., p. 353, pl. IV, figs. 1–4.

Reference Willman and Moczydłowska2008

Knollisphaeridium maximum (Yin) Knoll; Willman and Moczydłowska, p. 523, fig. 5E, F.

Reference Liu, Yin, Gao, Tang and Chen2009

Echinosphaeridium maximum; Liu et al., fig. 2m, n.

Reference Yin, Liu, Chen, Tang, Gao and Wang2009a

Echinosphaeridium maximum (Yin) Knoll; Yin et al., pl. 1, fig. 5.

Reference Chen, Yin, Liu, Gao, Tang and Wang2010

Echinosphaeridium maximum; Chen et al., fig. 2.2, 2.3.

Reference Sergeev, Knoll and Vorob'eva2011

Knollisphaeridium maximum (Yin) Willman and Moczydłowska; Sergeev et al., p. 1004, fig. 7.5.

Reference Willman and Moczydłowska2011

Knollisphaeridium maximum (Yin, Reference Yin1987; Knoll, Reference Knoll1992) Willman, 2007 [sic]; C. Yin et al., figs. 5f, 6e.

Reference Liu, Yin, Chen, Tang and Gao2013

Knollisphaeridium maximum; Liu et al., fig. 11N, O.

Reference Zeng, Chen, Li, Zhou, Zhang and Peng2013

Knollisphaeridium sp.; Zeng et al., fig. 4.3, 4.4.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Knollisphaeridium maximum (Yin) Willman and Moczydłowska; Liu et al., p. 83, figs. 44.4, 46, 47.

Reference Liu, Chen, Zhu, Li, Yin and Shang2014b

Knollisphaeridium maximum; Liu et al., fig. 8D, E.

Reference Liu, Chen, Zhu, Li, Yin and Shang2014b

Knollisphaeridium sp.; Liu et al., fig. 8H.

non Reference Xiao, Zhou, Liu, Wang and Yuan2014

Knollisphaeridium maximum (Yin) Willman and Moczydłowska; Xiao et al., p. 30, fig. 19.

Reference Ouyang, Guan, Zhou and Xiao2017

Knollisphaeridium maximum; Ouyang et al., fig. 9A–H.

Reference Liu and Moczydłowska2019

Knollisphaeridium maximum (Yin) Willman and Moczydłowska, emend. Liu and Moczydłowska, p. 118, fig. 64.

non Reference Liu and Moczydłowska2019

Knollisphaeridium maximum (Yin) Willman and Moczydłowska, emend. Liu and Moczydłowska, fig. 65.

Reference Ouyang, Zhou, Xiao, Chen and Shao2019

Knollisphaeridium maximum; Ouyang et al., fig. 13A–D.

Reference Vorob'eva and Petrov2020

Knollisphaeridium maximum (Yin) emend. Willman and Moczydłowska; Vorob'eva and Petrov, p. 374, pl. II, figs. 19, 20.

non Reference Grazhdankin, Nagovitsin, Golubkova, Karlova, Kochnev, Rogov and Marusin2020

Knollisphaeridium maximum; Grazhdankin et al., fig. 3D.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Knollisphaeridium maximum (Yin) Willman and Moczydłowska; Ouyang et al., fig. 15K–N.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Knollisphaeridium maximum (Yin) Willman and Moczydłowska; Shi et al., fig. 9A–C (illustrated in Fig. 16.5, 16.7, 16.8, one of the specimens described here).

Reference Li, Zhang, Han, Zhong, Ding, Wu and Liu2022

Knollisphaeridium maximum (Yin) Willman and Moczydłowska, emend. Liu and Moczydłowska; Ye et al., p. 42, fig. 28D–G.

Reference Golubkova2023

Knollisphaeridium maximum (Yin) emend. Willman; Golubkova, pl. 7, fig. 7.

Figure 16. Knollisphaeridium maximum (Yin, Reference Yin1987) Willman and Moczydłowska, Reference Willman and Moczydłowska2008, emend. Liu and Moczydłowska, Reference Liu and Moczydłowska2019. (1–3) PB202037, thin section 14HA-140-1, S53/4; circled 2 and 3 in (1) mark areas magnified in (2) and (3), respectively. (4, 6) PB202038, thin section 14HA-140-3, E28/4; circled 6 in (4) marks the area magnified in (6). (5, 7, 8) PB202039, thin section 21DC-6-9, H34; circled 7 and 8 in (5) mark areas magnified in (7) and (8), respectively; scale bar in (7) also applies to (8); red and blue arrowheads in (7) denote undeformed and slightly deformed processes, respectively.

Holotype

Specimen illustrated in Yin (Reference Yin1987, pl. 14, figs. 14, 15), thin section #Hm80-8-6, reposited at NIGPAS, from the Ediacaran Doushantuo Formation at Shipai in the Yangtze Gorges area, Hubei Province, South China (also illustrated in Liu and Moczydłowska, Reference Liu and Moczydłowska2019, fig. 64A–C).

Description and measurements

Vesicle large, spheroidal (some deformed to various degrees), covered by evenly and closely distributed, basally separated processes. Processes homomorphic, conical, most taper gradually toward a pointed tip. In some specimens, processes with (blue arrowhead in Fig. 16.7) and without (red arrowhead in Fig. 16.7) a basal expansion can be found on the same vesicle. No outer membrane is observed. Vesicle diameter 193–448 μm (N = 9, mean = 332 μm, SD = 114 μm); process length 9.5–19.0 μm (N = 11, mean = 14.9 μm, SD = 2.9 μm), 2.9–8.5% of vesicle diameter (N = 8, mean = 5.0%, SD = 2.0%); process basal width 2.4–5.6 μm (N = 12, mean = 3.7 μm, SD = 1.1 μm); 15–27 processes per 100 μm of vesicle periphery (N = 11, mean = 20, SD = 4 μm).

Material

Three illustrated specimens (Fig. 16) and nine additional specimens (including the two illustrated in Ouyang et al., Reference Ouyang, Guan, Zhou and Xiao2017, fig. 9A–C, 9F–H).

Remarks

Knollisphaeridium maximum is one of the most widely distributed Ediacaran acanthomorphic taxa and is distinctive in its large vesicle size and proportionally small, densely distributed, echinate conical processes. As most previously reported specimens of this species, the current specimens lack a multilayered membrane, which is considered diagnostic of K. maximum as emended by Liu and Moczydłowska (Reference Liu and Moczydłowska2019), but they possess all other diagnostic features of this species. Some specimens described here have processes with a slightly broadened basal expansion (blue arrowhead in Fig. 16.7), resembling processes of K. coniformum or K. triangulum. However, most processes do not have a basal expansion (red arrowhead in Fig. 16.7), indicating the apparent basal expansions may be taphonomic artifacts (e.g., subtle deformation at the process base during degradation and compression in early diagenesis).

Sixty-one specimens identified as small-sized Knollisphaeridium maximum by Liu and Moczydłowska (Reference Liu and Moczydłowska2019, fig. 65, vesicle diameter 40–86 μm and process length 4.2–10.5% of vesicle diameter) are here excluded from this species, and likely belong to Appendisphaera heliaca. These specimens have small vesicles and proportionally long processes, features that contradict the diagnosis of Knollisphaeridium. According to the emended diagnosis of Liu and Moczydłowska, Reference Liu and Moczydłowska2019, this genus is characterized by its medium-sized to large vesicle. Instead, these specimens are similar to A. heliaca in almost all morphological features, including vesicle size (55 μm for holotype, 43–72 μm for other published specimens; Liu and Moczydłowska, Reference Liu and Moczydłowska2019; Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021), relative process length (14.5% of vesicle diameter for holotype, 5.7–21.1% for other published specimens; Liu and Moczydłowska, Reference Liu and Moczydłowska2019; Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021), and process density and distribution.

Type species

Megasphaera inornata Chen and Liu, Reference Chen and Liu1986, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Other species

Megasphaera cymbala Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; M. ornata Xiao and Knoll, Reference Xiao and Knoll2000, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; M. patella Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; M. puncticulosa Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; M. minuscula Anderson et al., Reference Anderson, McMahon, Macdonald, Jones and Briggs2019 (although the validity of this species is questionable).

Remarks

Generally described together with acanthomorphs, Megasphaera is a special genus that contains both ornamented and unornamented species. To date, two unornamented species have been erected under the genus Megasphaera, including M. inornata and M. minuscula, with the former as the type species. Vesicle ornamentations are the key feature that distinguish acanthomorphs from sphaeromorphs (e.g., leiospheres). Therefore, the validity of M. inornata (thus also Megasphaera) is related with how it differs from leiospheres. Morphological and structural differences between M. inornata and leiospheres are threefold. Firstly, although leiospheres also contain large species, they are mostly small to medium-sized (Butterfield et al., Reference Butterfield, Knoll and Swett1994). On the contrary, Megasphaera was erected emphasizing its large size (Chen and Liu, Reference Chen and Liu1986), and a large vesicle is still the major diagnostic feature of this genus (Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014, in which a large vesicle is defined as vesicle diameter > 200 μm). Secondly, M. inornata exhibits a cell division sequence as recorded by various numbers (one to more than 100) of uniformly shaped and tightly packed daughter cells within the vesicle, which were separately named Megaspheara, Parapandorina, and Megaclonophycus (Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014). Leiospheres may also contain cells within the vesicle, but these cells are irregular in shape and size (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a), do not form a closely compacted spheroidal body, and do not form a cell division sequence as generally seen in Megasphaera specimens. Third and importantly, the smooth-walled M. inornata may represent a taphonomic or developmental variation of M. ornata, which does have a sculptured vesicle surrounding a smooth vesicle, therefore these two species may be biologically conspecific (Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014). However, the above-mentioned features that distinguish M. inornata from leiospheres do not apply to M. minuscula, which has a relatively small vesicle (inconsistent with current diagnosis of Megasphaera) that contains internal bodies of various size and has no ornamented counterpart. Thus, it is uncertain whether M. minuscula should be accepted as a species of Megasphaera.

Megasphaera inornata Chen and Liu, Reference Chen and Liu1986, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014
 Figure 17.1

Reference Chen and Liu1986

Megasphaera inornata Chen and Liu, p. 51, pl. 1, fig. 4.

Reference Xue, Tang, Yu and Zhou1995

Parapandorina raphospissa Xue et al., p. 692, pl. I, figs. 1–3.

Reference Xue, Tang, Yu and Zhou1995

Parapandorina beidoushanensis Xue et al., p. 692, pl. II, figs. 1, 3–5.

Reference Xue, Tang, Yu and Zhou1995

Parapandorina beidoushanensis var. cylindrica Xue et al., p. 693, pl. II, fig. 2.

Reference Xue, Tang, Yu and Zhou1995

Megacolonophycus onustus Xue et al., p. 695, pl. III, figs. 3, 4, pl. IV, figs. 1–6, pl. V, figs. 2, 6–9.

Reference Xue, Tang, Yu and Zhou1995

Colossotetrahedrion ovimpositum Xue et al., p. 696, pl. V, figs. 3, 5.

Reference Xiao and Knoll2000

Megasphaera inornata Chen and Liu, Reference Chen and Liu1986, emend. Xiao and Knoll, p. 773, fig. 3.1, 3.2, 3.4, 3.5, 3.7, 3.11.

Reference Zhou, Chen and Xue2002

Megasphaera inornata Chen and Liu; Zhou et al., p. 182, pl. II, figs. 1, 2.

Reference Zhou, Yuan, Xiao, Chen and Xue2004b

Parapandorina raphospissa Xue et al.; Zhou et al., pl. VI, figs. 5–9.

Reference Zhou, Yuan, Xiao, Chen and Xue2004b

Megacolonophycus onustus Xue et al.; Zhou et al., pl. VI, fig. 10.

Reference Xie, Zhou, Mcfadden, Xiao and Yuan2008

Parapandorina raphospissa (Xue et al.) Xiao and Knoll; Xie et al., p. 285, pl. II, fig. 4.

Reference Xie, Zhou, Mcfadden, Xiao and Yuan2008

Megacolonophycus onustus Xue et al.; Xie et al., p. 284, pl. II, figs. 5, 6.

Reference Yin, Liu, Gao, Tang and Chen2009b

Megasphaera inornata Chen and Liu; Yin et al., fig. 3a, b.

Reference Yin, Liu, Gao, Tang and Chen2009b

Megacolonophycus onustus Xue et al.; Yin et al., fig. 4b–d.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Megasphaera inornata Chen and Liu, emend. Xiao et al., p. 35.

Reference Ye, Tong, An, Tian, Zhao and Zhu2015

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Ye et al., p. 50, pl. II, figs. 1–13.

Reference Nie, Liu and Dong2017

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Nie et al., p. 380, fig. 10.

Reference Ouyang, Zhou, Xiao, Chen and Shao2019

Megasphaera inornata; Ouyang et al., fig. 9L.

Reference Shang, Liu and Moczydłowska2019

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Shang et al., p. 24, fig. 14A, B.

Reference Ouyang, Zhou and Liu2020

Megasphaera inornata; Ouyang et al., figs. 3A–J, 4.

Reference Shang, Liu and Liu2020

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Shang and Liu, p. 158, fig. 5C.

Reference Yang, Pang, Chen, Zhong and Yang2020

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Yang et al., p. 9, fig. 3.

Reference Shang and Liu2020

Acritarcha gen. et sp. indet.; Shang and Liu, p. 159, fig. 6D, E.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Ouyang et al., fig. 16A–D.

Reference Ye, Li, Tong, An, Hu and Xiao2022

Megasphaera inornata Chen and Liu, emend. Xiao et al.; Ye et al., p. 47, fig. 49.

Figure 17. (1) Megasphaera inornata Chen and Liu, Reference Chen and Liu1986, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; PB202040, thin section 19SDP-1-13, K42/2. (2) Megasphaera ornata Xiao and Knoll, Reference Xiao and Knoll2000, emend. Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; PB202041, thin section 19SDP-1-22, P39/2; red arrowhead denotes the outer surface of the sculptured vesicle wall.

Neotype

The specimen illustrated by Xiao and Knoll (Reference Xiao and Knoll2000, fig. 3.1) was designated as a neotype (HUHPC-64837, SRA-1, photo 419) by Xiao et al. (Reference Xiao, Zhou, Liu, Wang and Yuan2014).

Description and measurements

A large, oval vesicle with a diameter of about 896 μm. No ornamentation is observed.

Material

One illustrated specimen (Fig. 17.1).

Remarks

With a relatively regular shape, the described specimen is likely an acritarch vesicle without ornamentation. Its large size and uniformly thick vesicle wall are comparable to those of Megasphaera inornata. No primary internal structures, such as internal bodies, are present, likely due to degradation and secondary mineral precipitation, as evinced by the abundance of botryoidal cements and spherules, which are interpreted as possible bacterial infection in degrading specimens (Xiao and Knoll, Reference Xiao and Knoll1999).

Holotype

HUHPC-62990, reposited at the Harvard University Herbaria Paleobotanical Collection, from the Ediacaran Doushantuo Formation in the Weng'an area, Guizhou Province, South China (Xiao and Knoll, Reference Xiao and Knoll2000, fig. 5.4).

Description and measurements

A large, spheroidal body with a diameter of about 709 μm, surrounded by an outer layer with sculptures of various size.

Material

One illustrated specimen (Fig. 17.2).

Remarks

This specimen is assigned to Megasphaera ornata based on its large vesicle and an outer layer with sculptures that manifest as indentations in thin-section view (red arrowhead in Fig. 17.2). The light-colored zone between the outer sculpture layer and the internal spheroidal body represents secondary cement of micro-quartz. The uneven thickness of the light-colored zone may be caused by taphonomic deformation of the outer vesicle wall and displacement of the internal spheroidal body.

Type species

Mengeosphaera chadianensis (Chen and Liu, Reference Chen and Liu1986) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Other species

Mengeosphaera angusta Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. bellula Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. constricta Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. eccentrica Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; M. flammelata Liu and Moczydłowska, Reference Liu and Moczydłowska2019; M. gracilis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. grandispina Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. latibasis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. lunula Liu and Moczydłowska, Reference Liu and Moczydłowska2019; M. mamma Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022; M. matryoshkaformis Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021; M. membranifera Shang, Liu, and Moczydłowska, Reference Liu and Moczydłowska2019; M. minima Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. reticulata (Xiao and Knoll, Reference Xiao and Knoll1999) Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014; M. spinula Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. stegosauriformis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; M. uniformis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a.

Mengeosphaera bellula Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a
 Figure 18.1–18.3

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Mengeosphaera bellula Liu et al., p. 90, figs. 51.2, 52, 53.

Figure 18. (1–3) Mengeosphaera bellula Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, PB202042, thin section 19CW-6-12, K33; circled 2 and 3 in (1) mark areas magnified in (2) and (3), respectively. (4–8) Mengeosphaera constricta Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, PB202043, thin section 14HA-115-2, W43/2; circled 5 in (4) marks the same area magnified in (5) and (6) at different focal levels; circled 7 and 8 in (4) mark areas magnified in (7) and (8), respectively. (9–14) Mengeosphaera gracilis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a. (9, 10, 12) PB202044, thin section 19TP-1-12, H43/1; circled 10 and 12 in (9) mark areas magnified in (10) and (12), respectively; (11, 13, 14) PB202045, thin section 19CW-6-15, G36; circled 13 and 14 in (11) mark areas magnified in (13) and (14), respectively. Scale bar in (8) represents 5 μm and applies to (5–7); scale bar in (14) applies to (13).

Holotype

IGCAGS-NPIII-266, reposited at Institute of Geology, Chinese Academy of Geological Sciences, from Member III of the Ediacaran Doushantuo Formation at Niuping section in the Yangtze Gorges area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 52.1–52.3).

Description and measurements

Vesicle small, originally spheroidal, with homomorphic biform processes closely distributed on the vesicle. The process is composed of a basal expansion that tapers rapidly toward a long and thin apical spine. Specimen illustrated (Fig. 18.1–18.3): vesicle diameter about 73 μm, process length about 17.1 μm (23.5% of vesicle diameter) and basal width about 5.6 μm, with about 21 processes per 100 μm of vesicle periphery; length (height) of basal part (from vesicle wall to the point where the process begins to taper significantly) about 2.8 μm (16.4% of process total length), apical spine width (diameter) about 0.9 μm. The other available specimen: vesicle diameter not measured due to compression, process length about 17.7 μm and basal width about 5.4 μm, about 25 processes per 100 μm of vesicle periphery; length of basal part about 4.8 μm (27.1% of process total length), apical spine width about 1.1 μm.

Material

One illustrated specimen (Fig. 18.1–18.3) and one additional specimen.

Remarks

The two described specimens have densely arranged biform processes with a basal expansion and a relatively long, thin apical spine. These features, as well as their measurements, are similar to those in Mengeosphaera bellula (holotype 75 μm in vesicle diameter, 16 μm in process length or 21% of vesicle diameter, and 5 μm in process basal width). The two available specimens can alternatively be compared to M. chadianensis, but M. chadianensis commonly has larger vesicles (500–800 μm in diameter for the holotype), and thus the processes of M. chadianensis are proportionally shorter and smaller. In addition, the apical spine of M. chadianensis typically takes a smaller percentage of the overall process length than in M. bellula. Thus, the two specimens described here are more appropriately identified as M. bellula.

Two specimens from the Doushantuo Formation in the Shennongjia area that are identified as Mengeosphaera chadianensis in Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022, figs. 32A–C, 33A, B) have homomorphic and biform processes resembling those in M. bellula, with the lower part of the basal expansion more or less cylindrical, supporting a long and distally tapering apical spine. Process morphology, proportional process length, and relatively long apical spine of the two Shennongjia specimens are more similar to previously reported M. bellula than to M. chadianensis. However, the two Shennongjia specimens (vesicle diameter about 142 μm for fig. 32A and about 138 μm for fig. 33A in Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022) are both much larger than M. bellula specimens from the type locality in the Yangtze Gorges area (50–90 μm in vesicle diameter). Thus, these two specimens are questionably retained as M. chadianensis.

Holotype

IGCAGS–WFG–826, reposited at Institute of Geology, Chinese Academy of Geological Sciences, from lower Member III of the Ediacaran Doushantuo Formation at Wangfenggang section in the Yangtze Gorges area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 56.1, 56.2).

Description and measurements

Vesicle spheroidal, with uniform processes closely arranged on vesicle surface, although only three processes completely preserved. Processes consist of an overall inflated, near-cylindrical basal part and a conical terminal part. The inflated basal expansion is constricted at the contact with the vesicle wall (Fig. 18.5–18.8), and the terminal part tapers gradually to a pointed tip, thus forming an onion-like process. The processes are separated from each other at their base, but are in contact at the inflated basal expansion. Vesicle diameter about 110 μm; process length about 15.6 μm (14.2% of vesicle diameter), maximum width of basal expansion about 9.7 μm, and width of constricted base about 6.9 μm; length of basal expansion (from process base to the point where the process begins to taper significantly) about 11.1 μm (71.2% of process total length).

Material

One illustrated specimen (Fig. 18.4–18.8).

Remarks

This specimen was previously published in Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017) as Mengeosphaera spicata. Although Liu and Moczydłowska (Reference Liu and Moczydłowska2019) synonymized M. spicata and M. constricta, they did not provide any explanation. We follow Xiao et al. (Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022) to tentatively accept this synonymy, and thus reassign this specimen to M. constricta. Due to the poor preservation, only three processes (magnified in Fig. 18.5–18.8) are completely preserved with a discernable basal constriction. The consistent morphology of these three processes, however, indicates that the basal constriction is not a taphonomic artifact.

Holotype

IGCAGS-WFG-727, reposited at Institute of Geology, Chinese Academy of Geological Sciences, from lower Member III of the Ediacaran Doushantuo Formation at Wangfenggang section in the Yangtze Gorges area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 60.1, 60.2).

Description and measurements

Vesicle large and spheroidal, bearing densely distributed, basally connected biform processes. Processes uniform, with a conical basal expansion and a thin cylindrical apical spine. First specimen (Fig. 18.9, 18.10, 18.12): vesicle diameter about 226 μm; process length about 17.4 μm (7.7% of vesicle diameter), basal width about 6.4 μm, basal expansion length about 4.8 μm (27.6% of process total length); about 14 processes per 100 μm of vesicle periphery. Second specimen (Fig. 18.11, 18.13, 18.14): vesicle diameter about 250 μm; process length about 30.4 μm (12.2% of vesicle diameter), basal width about 8.5 μm, basal expansion length about 6.9 μm (22.7% of process total length); about seven processes per 100 μm of vesicle periphery.

Material

Two illustrated specimens (Fig. 18.9–18.14).

Remarks

Mengeosphaera gracilis can be differentiated from Cavaspina basiconica by its clearly defined biform processes with a more prominent and wider basal expansion. The two available specimens have processes with a conical basal expansion, unlike the deflated base of processes in C. basiconica. These two specimens also differ from Appendisphaera hemisphaerica in their relatively shorter and thicker process apical spine (process length ~14.3% of vesicle diameter in holotype of A. hemisphaerica), and especially the smaller process density (~21 processes per 100 μm of vesicle periphery in the holotype of A. hemisphaerica).

Mengeosphaera latibasis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, emend. Liu and Moczydłowska, Reference Liu and Moczydłowska2019
 Figure 19.1, 19.2

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Mengeosphaera latibasis Liu et al., p. 97, figs. 51.7, 62.

?Reference Nie, Liu and Dong2017

Mengeosphaera latibasis Liu et al.; Nie et al., p. 376, fig. 6.3–6.7.

Reference Ouyang, Guan, Zhou and Xiao2017

Mengeosphaera latibasis?; Ouyang et al., fig. 8K–N (the specimen described here and illustrated in Fig. 19.1, 19.2).

Reference Liu and Moczydłowska2019

Mengeosphaera latibasis Liu et al., emend. Liu and Moczydłowska, p. 133, fig. 72.

Reference Liu, Qi, Fan, Guo and Pei2021

Mengeosphaera latibasis Liu et al., emend. Liu and Moczydłowska; Ouyang et al., fig. 17A, B.

Figure 19. (1, 2) Mengeosphaera latibasis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, emend. Liu and Moczydłowska, Reference Liu and Moczydłowska2019, PB202046, thin section 14HA-115-1, T49/4; circled 2 in (1) marks the area magnified in (2). (3) Mengeosphaera minima Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, PB202047, thin section 21DC-5-4, T31/2. (4) Mengeosphaera minima? PB202048, thin section 21DC-3-1, G23/3. (5–11) Mengeosphaera mamma Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022. (5–7) PB202049, thin section 21LHK-1-10, L38/1; circled 6 and 7 in (5) mark areas magnified in (6) and (7), respectively; (8, 10) PB202050, thin section 21MJD-1-10, L45; circled 10 in (8) marks the area magnified in (10); (9, 11) PB202051, thin section 21MJD-1-11, L33; circled 11 in (9) marks the area magnified in (11). Red arrowheads in (2), (5–7), (10), and (11) denote reflection points of biform processes; red arrowheads in (4) denote the basally joined, strongly inflated processes.

Holotype

IGCAGS–NPIII–540, reposited at Institute of Geology, Chinese Academy of Geological Sciences, from the upper Member III of the Ediacaran Doushantuo Formation at Niuping section in the Yangtze Gorges area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 62.1, 62.2).

Description and measurements

Vesicle large, originally spheroidal but slightly deformed. Processes densely arranged on vesicle surface, basally connected or separated. Processes biform, with a broad, obtusely conical, and slightly inflated basal expansion, and a relatively thick but flexible apical spine that is more or less cylindrical in shape. Vesicle diameter about 465 μm; process length about 52.2 μm (11.2% of vesicle diameter), basal width about 31.2 μm, basal expansion length about 16.6 μm (31.8% of process total length), apical spine width about 4.9 μm; about three processes per 100 μm of vesicle periphery.

Material

One illustrated specimen (Fig. 19.1, 19.2).

Remarks

Mengeosphaera latibasis is distinct in its inflated basal expansion that is wider than long. In many Mengeosphaera specimens, processes with a slightly obtuse basal expansion are common (as in the two specimens of M. gracilis described above), but basal expansions that are twice as wide as they are long are characteristic of M. latibasis.

Holotype

The specimen illustrated in Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 35A–C), thin section LHGd3 + 30 cm-1–17 (36.3×76.1), reposited at China University of Geosciences (CUG), Wuhan, China, from the Ediacaran Doushantuo Formation at Lianhuacun section in Shennongjia area, Hubei Province, South China.

Description and measurements

Most specimens are not entirely captured in thin section due to their large size. Vesicles range from oval to completely compressed, but were originally spheroidal. Processes large, biform, with the apical spine in most specimens poorly preserved and their full length unavailable. Four specimens with adequately preserved vesicles reveal a vesicle diameter of 350–632 μm, with the largest illustrated in Figure 19.8. Process basal width 37.7–77.0 μm (N = 9, mean = 50.5 μm, SD = 11.3 μm), basal expansion length 30.0–69.0 μm (N = 5, mean = 40.0 μm, SD = 16.3 μm), apical spine width 6.8–18.6 μm (N = 2); 1–2 processes per 100 μm of vesicle periphery. In some better-preserved processes (e.g., Fig. 19.10, 19.11), the basal expansion is as long as or longer than it is wide, and it is possible that the measurements of basal expansion length given above may be underestimates when the basal expansions are cut obliquely (in which case the apical spines are often missed in the thin section).

Material

Three illustrated specimens (Fig. 19.5–19.11) and six additional specimens (including the one illustrated in Shi et al., Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 8E, F).

Remarks

Of all Mengeosphaera species, M. flammelata, M. grandispina, M. mamma, and M. stegosauriformis have processes tens of micrometers in basal width. Among these four species, processes are flame-shaped in M. flammelata, have a conical and somewhat deflated basal expansion in M. grandispina, have a strongly inflated basal expansion in M. stegosauriformis. The nine specimens described here are most similar to M. mamma in both process size and shape.

The specimen published as “unnamed form A” from the Doushantuo Formation at the Diaoyapo section in the Yangtze Gorges area (Yin, Reference Yin1996) has processes with large, significantly inflated basal expansions (35–55 μm in basal length, ~40 μm in basal width), and cylindrical apical spine. These features fall within the perimeter of Mengeosphaera mamma, and this specimen is here reassigned to M. mamma.

Holotype

IGCAGS–NPIII–090A, reposited at Institute of Geology, Chinese Academy of Geological Sciences, from the upper Member III of the Ediacaran Doushantuo Formation at Niuping section in the Yangtze Gorges area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 63.1).

Description and measurements

Vesicle small, spheroidal, with uniform processes evenly distributed on the vesicle. Processes closely arranged but basally separated. Processes biform, with a conical basal expansion and a thin, cylindrical or distally tapering apical spine. The specimen illustrated in Figure 19.3 has a vesicle diameter of about 54 μm, process length about 7.0 μm (13.0% of vesicle diameter), basal expansion width about 4.1 μm, basal expansion length about 3.0 μm (42.9% of process total length), with about 14 processes per 100 μm of vesicle periphery. The other specimen has a vesicle diameter of about 92 μm, process length about 20.3 μm (22.0% of vesicle diameter), basal expansion width about 4.2 μm, basal expansion length about 4.6 μm (22.7% of process total length); process density unavailable due to poor preservation.

Material

One illustrated specimen (Fig. 19.3) and one additional specimen.

Remarks

Most Mengeosphaera species have large or at least medium-sized vesicles. To date, M. bellula, M. minima, and M. stegosauriformis are the only three Mengeosphaera species that have small vesicles, with M. minima being the smallest of all. The two available specimens are assigned to M. minima for their small size with biform processes that consist of a generally conical and proportionally large (at least 20% of process total length) basal expansion.

Description and measurements

Vesicle small, spheroidal, bearing basally connected uniform processes. Processes biform, with clearly inflated basal expansions that take up about half of the total length of processes. Vesicle diameter about 48 μm, process length about 5.8 μm (12.1% of vesicle diameter) and basal width about 3.1 μm, length of basal expansion about 3.0 μm (51.7% of process total length), with about 32 processes per 100 μm of vesicle periphery.

Material

One illustrated specimen (Fig. 19.4).

Remarks

Resembling Mengeosphaera minima in the small vesicle size and the biform processes, this specimen is distinct in its basally connected and strongly inflated processes (red arrowheads in Fig. 19.4). Since these features appear consistently on all processes of this specimen, they are unlikely to be taphonomic artifacts, and probably represent morphological variations of taxonomic importance. Since there is only one such specimen in our collection, it is uncertain whether these variations are intraspecific or interspecific in nature. As such, we tentatively assign this specimen in an open nomenclature but note its similarity to M. minima.

Type species

Tanarium conoideum Kolosova, Reference Kolosova1991, emend. Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993.

Other species

Tanarium acus Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; T. araithekum Grey, Reference Grey2005; T. capitatum Liu and Moczydłowska, Reference Liu and Moczydłowska2019; T. columnatum Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022; T. cuspidatum (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) Liu and Moczydłowska, Reference Liu and Moczydłowska2019; T. digitiforme (Nagovitsin and Faizullin in Nagovitsin et al., Reference Nagovitsin, Faizullin and Yakshin2004) Sergeev, Knoll, and Vorob'eva, Reference Sergeev, Knoll and Vorob'eva2011; T. elegans Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; T. gracilentum (Yin in Yin and Liu, Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988) Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021; T. irregulare Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993; T. longidigitatum Golubkova, Reference Golubkova2023; T. mattoides Grey, Reference Grey2005; T. megaconicum Grey, Reference Grey2005; T.? minimum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; T.? muntense Grey, Reference Grey2005; T. obesum Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; T. paucispinosum Grey, Reference Grey2005; T. pilosiusculum Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009; T. pluriprotensum Grey, Reference Grey2005; T. pycnacanthum Grey, Reference Grey2005; T. triangulare (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) Liu and Moczydłowska, Reference Liu and Moczydłowska2019; T. tuberosum Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993; T. uniformum Liu and Moczydłowska, Reference Liu and Moczydłowska2019; T. varium Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; T. victor Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Remarks

Like Appendisphaera, Tanarium encompasses a remarkably large range of morphological variations. The currently accepted species of Tanarium contain taxa with homomorphic (e.g., T.? muntense) or heteromorphic (T. irregulare) processes, with slim (e.g., T. gracilentum) to obtusely conical (e.g., T. tuberosum) processes, with cylindrical (e.g., T. digitiforme) to biform (e.g., T. triangulare) processes, with terminally pointed (e.g., T. acus) to bifurcated (e.g., T. victor) processes, with sparsely arranged (e.g., T. megaconicum) to densely arranged (e.g., T. pycnacanthum) processes, and with relatively short (process length <10% of vesicle diameter, e.g., T. pilosiusculum) to remarkably long (process length >50% of vesicle diameter, e.g., T. mattoides) processes. These morphological variations make it nearly impossible to define the genus Tanarium, and a taxonomical revision, preferably based on morphometric analyses, is urgently needed.

Tanarium cf. T. capitatum Liu and Moczydłowska, Reference Liu and Moczydłowska2019
 Figure 20.1, 20.2

cf. Reference Liu and Moczydłowska2019

Tanarium capitatum Liu and Moczydłowska, p. 143, fig. 79.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Tanarium cf. T. capitatum; Shi et al., fig. 8N, O (the specimen described here and illustrated in Fig. 20.1, 20.2).

Figure 20. (1, 2) Tanarium cf. T. capitatum Liu and Moczydłowska, Reference Liu and Moczydłowska2019, PB202052, thin section 21DC-2-35, M32/1, showing the same area at different focal levels. (3, 5) Tanarium conoideum Kolosova, Reference Kolosova1991, emend. Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, PB202053, thin section 21DC-5-4, R43/3, showing the same area at different focal levels. (4, 6, 7) Tanarium paucispinosum Grey, Reference Grey2005: (4) PB202054, thin section 19CW-6-9, N35/3; (6, 7) PB202055, thin section 19CW-5-29, H38, showing the same area at different focal levels.

Description and measurements

Vesicle large, compressed but originally spheroidal. Processes evenly distributed with moderate density, basally departed. Processes conical, with a wide base and tapering gradually toward a thin terminal end. Vesicle diameter approximately 348 μm. The full length of processes is difficult to obtain due to the relatively large size of the processes (so the terminal part is often not captured in thin sections), with one measurement of about 62.6 μm (18.0% of vesicle diameter) and two partially preserved processes 42.5 μm and 49.6 μm in length. Process basal width about 16.3 μm, process basal spacing about 13.2 μm, and about 3 processes per 100 μm of vesicle periphery.

Material

One specimen illustrated in Figure 20.1, 20.2.

Remarks

The described specimen is morphologically similar to Tanarium capitatum in vesicle size, process shape and proportional size, and process density and distribution. However, it lacks the key diagnostic feature of T. capitatum—the knob-like, bulge process tip. It is possible that the process tips are not preserved due to taphonomic loss, and this specimen is otherwise more similar to T. capitatum than to other species. The processes in this specimen are also similar to those of T. pilosiusculum in proportional length, but they are thinner and more acutely conical than processes in T. pilosiusculum (Vorob'eva et al., Reference Vorob'eva, Sergeev and Knoll2009). Therefore, we compare this specimen to T. capitatum but tentatively place it in an open nomenclature.

Tanarium conoideum Kolosova, Reference Kolosova1991, emend. Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993
Figure 20.3, 20.5

Reference Kolosova1991

Tanarium conoideum Kolosova, p. 57, fig. 5.1–5.3.

Reference Moczydłowska, Vidal and Rudavskaya1993

Tanarium conoideum Kolosova, emend. Moczydłowska, Vidal, and Rudavskaya, p. 514, 516, text-fig. 10C–D.

Reference Moczydłowska2005

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Moczydłowska, p. 302, fig. 7A, C, E.

non Reference Grey2005

Tanarium conoideum Kolosova; emend. Moczydłowska et al.; Grey, p. 299, figs. 212, 213.

non Reference Willman, Moczydłowska and Grey2006

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Willman et al., p. 32, pl. VI, figs. 1, 2.

non Reference Willman and Moczydłowska2008

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Willman and Moczydłowska, p. 526, fig. 12C.

non Reference Vorob'eva, Sergeev and Chumakov2008

Tanarium conoideum Kolosova; Vorob'eva et al., fig. 2a.

non Reference Vorob'eva, Sergeev and Knoll2009

Tanarium conoideum Kolosova, Moczydłowska et al.; Vorob'eva et al., p. 180, fig. 7.4, 7.7.

non Reference Yin, Liu, Chen, Tang, Gao and Wang2009a

Tanarium conoideum (Kolosova, Reference Kolosova1991) Moczydłowska et al. [sic]; Yin et al., pl. I, figs. 3, 4.

non Reference Golubkova, Raevskaya and Kuznetsov2010

Tanarium conoideum (Kolosova) emend. Moczydłowska et al. [sic]; Golubkova et al., pl. III, fig. 7, pl. IV, fig. 2.

Reference Sergeev, Knoll and Vorob'eva2011

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Sergeev et al., p. 1005, fig. 6.1, 6.2.

non Reference Yin, Liu, Awramik, Chen, Tang, Gao, Wang and Riedman2011

Tanarium conoideum (Kolosova, Reference Kolosova1991) Moczydłowska et al. [sic]; C. Yin et al., fig. 6c (the same specimen as pl. I, figs. 3, 4 in Yin et al., Reference Yin, Liu, Chen, Tang, Gao and Wang2009a).

non Reference Liu, Yin, Chen, Tang and Gao2013

Tanarium conoideum; Liu et al., fig. 11A.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Xiao et al., p. 51, fig. 33.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Liu et al., p. 109, figs. 76.2, 77.

Reference Shang, Liu and Moczydłowska2019

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Shang et al., p. 26, fig. 16A–E.

Reference Vorob'eva and Petrov2020

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Vorob'eva and Petrov, p. 374, pl. I, fig. 15.

non Reference Yang, Pang, Chen, Zhong and Yang2020

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Yang et al., p. 6, fig. 2K.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Tanarium conoideum; Shi et al., fig. 9D, E (the specimen described here and illustrated in Fig. 21.3, 21.5).

Reference Ye, Li, Tong, An, Hu and Xiao2022

Tanarium conoideum Kolosova, emend. Moczydłowska et al.; Ye et al., p. 65, figs. 42, 43A–E.

Reference Golubkova2023

Tanarium conoideum (Kolosova) emend. Moczydłowska [sic]; Golubkova, pl. 7, fig. 6.

Figure 21. Tanarium pilosiusculum Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009. (1–4) PB202056, thin section 19CW-6-15, O41; circled 2–4 in (1) mark areas magnified in (2–4), respectively; (5–7) PB202057, thin section 21LHK-1-10, M31/2; circled 6 and 7 in (5) mark areas magnified in (6) and (7), respectively.

Holotype

YIGS Nr 87-115, reposited at the Geological Museum of Yakutian Institute of Geologic Sciences (present Diamond and Precious Metal Geology Institute, Siberian Branch, Russian Academy of Sciences), from the Ediacaran Kursov Formation, Anabar area, eastern Siberia (Kolosova, Reference Kolosova1991, p. 57, fig. 5.1, 5.2).

Description and measurements

Vesicle spheroidal, medium-sized, bearing evenly distributed processes. Processes uniform, conical, distally tapering toward a pointed tip. Vesicle diameter about 108 μm; process length about 24.9 μm (23.1% of vesicle diameter), basal width about 8.8 μm, about seven processes per 100 μm of vesicle periphery.

Material

One specimen illustrated in Figure 20.3, 20.5.

Remarks

Previously published specimens of Tanarium conoideum represent a large range of morphological variations. The specimen described here is comparable to the holotype of T. conoideum in many morphological aspects, including the vesicle size, proportional size of processes, and process shape (for comparison, the holotype of T. conoideum has a vesicle diameter of ~114 μm, process length ~34.3 μm, and process basal width ~16.2 μm, as remeasured on fig. 5.1–5.3 of Kolosova, Reference Kolosova1991). The specimen described here differs from the holotype and many other published T. conoideum specimens in its greater process density; the holotype of T. conoideum has only about 1–2 processes per 100 μm of vesicle periphery, although it should be noted that the holotype has a relatively larger vesicle. However, process density is somewhat variable among previously published specimens of T. conoideum (e.g., ~4 processes per 100 μm of vesicle periphery in both Moczydłowska, Reference Moczydłowska2005, fig. 7C and in Golubkova, Reference Golubkova2023, pl. 7, fig. 6, and about 7 processes per 100 μm of vesicle periphery in Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014, fig. 33.3). Thus, we chose to place the specimen illustrated in Figure 20.3 and 20.5 in T. conoideum.

Holotype

CPC 36552, reposited at Commonwealth Palaeontological Collection (CPC) at Geoscience Australia, Canberra, from the Ediacaran Wilari Dolomite Member of Observatory Hill I drill core in Officer Basin, South Australia (Grey, Reference Grey2005, fig. 237D).

Description and measurements

Vesicle medium-sized to large, originally spheroidal but may be deformed to different degrees. A small number of conical processes unevenly distributed on the vesicle wall. Vesicle diameter 149–201 μm (N = 5, mean = 170 μm, SD = 19 μm); processes length 38.1–83.8 μm (N = 7, mean = 62.2 μm, SD = 15.4 μm) and 23.7–36.2% of vesicle diameter (N = 4, mean = 32.8%, SD = 6.1%); process basal width 9.7–16.2 μm (N = 9, mean = 12.1 μm, SD = 2.0 μm); on average one process per 100 μm of vesicle periphery (measured on one specimen illustrated in Figure 20.6, 20.7).

Material

Two illustrated specimens (Fig. 20.4, 20.6, 20.7) and seven additional specimens.

Remarks

The described specimens are placed in Tanarium paucispinosum mainly for their sparsity of processes, which is the key diagnosis of T. paucispinosum. These two specimens also resemble specimens of T. paucispinosum reported from Australia in proportional length of the processes (~20–40% of vesicle diameter, calculated based on dimensions provided in Grey, Reference Grey2005) and the thin conical shape of the processes, although the vesicle size of the current specimens is greater than the Australian specimens (64–148 μm in vesicle diameter).

Holotype

Specimen 14700-74 (illustrated in Vorob'eva et al., Reference Vorob'eva, Sergeev and Knoll2009, fig. 7.1), reposited at the Paleontological Collection of the Geological Institute of the Russian Academy of Sciences, from the upper part of the early Ediacaran Vychegda Formation of the Kel'tminskaya-1 borehole in the East European Platform, Russia.

Description and measurements

Vesicle spheroidal, bearing a moderate number of relatively short processes randomly distributed on the vesicle. Processes conical and simple in shape, taper gradually toward a pointed tip. The specimen illustrated in Figure 21.1–21.4 has a vesicle diameter of about 201 μm, process length about 26.9 μm (13.4% of vesicle diameter), and basal width about 12.0 μm, with about 2–3 processes per 100 μm of vesicle periphery. The specimen illustrated in Figure 21.5–21.7 has a vesicle diameter of about 257 μm, process length about 49.7 μm (19.4% of vesicle diameter), and basal width about 21.5 μm, with 1–2 processes per 100 μm of vesicle periphery. The third specimen (illustrated in Shi et al., Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 9F, G) has a vesicle diameter of about 84 μm, process length about 11.0 μm (12.9% of vesicle diameter), and basal width about 12.3 μm, with about 7 processes per 100 μm of vesicle periphery.

Material

Two specimens illustrated in Figure 21, and one additional specimen illustrated in Shi et al. (Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022, fig. 9F, G).

Remarks

Tanarium pilosiusculum is characterized by processes proportionally shorter (~5–10% of vesicle diameter) than those of other Tanarium species (typically >20% of vesicle diameter, as proposed by Grey, Reference Grey2005). Compared with the holotype of T. pilosiusculum, specimens described in this paper have proportionally longer processes that exceed 10% and can be up to 20% of vesicle diameter. However, they are otherwise comparable to T. pilosiusculum in process density and distribution; both have numerous conical and basally separated processes that are occasionally wider than long. They also meet the diagnosis of T. pilosiusculum in having processes “generally shorter than those of other Tanarium species,” (Vorob'eva et al., Reference Vorob'eva, Sergeev and Knoll2009, p. 182) considering that most other Tanarium species are characterized by longer processes that are greater than 20% of vesicle diameter. We note that other acanthomorph taxa, including several species of Appendisphaera, Urasphaera fungiformis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, and Variomargosphaeridium floridum Nagovitsin and Moczydłowska in Moczydłowska and Nagovitsin, Reference Moczydłowska and Nagovitsin2012, also have processes that are 10–20% of vesicle diameter, but their processes can be easily distinguished from the simple conical processes in the specimens described here, which are most appropriately placed in T. pilosiusculum on account of their process morphology and density.

Tanarium triangulare (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) Liu and Moczydłowska, Reference Liu and Moczydłowska2019
 Figure 22.1–22.3

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Mengeosphaera triangularis Liu et al., p. 103, figs. 51.13, 68.

Reference Ouyang, Guan, Zhou and Xiao2017

Mengeosphaera? cuspidata; Ouyang et al., fig. 9I–K (specimens described here).

Reference Ouyang, Guan, Zhou and Xiao2017

Mengeosphaera chadianensis; Ouyang et al., fig. 9L, M (specimen described here).

Reference Liu and Moczydłowska2019

Tanarium triangularis (Liu et al.) Liu and Moczydłowska, p. 151, fig. 85.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Tanarium triangulare (Liu et al.) Liu and Moczydłowska; Ouyang et al., fig. 20D.

Figure 22. (1–3) Tanarium triangulare (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) Liu and Moczydłowska, Reference Liu and Moczydłowska2019: (1, 2) PB202058, thin section 14HA-140-5, F24/1, same area at different focal levels; (3) PB202059, thin section 14HA-140-3, D31/1. (4) Tanarium tuberosum Moczydłowska, Vidal, and Rudavskaya, Reference Moczydłowska, Vidal and Rudavskaya1993, PB202060, thin section 21DC-4-11, U45. Red arrowheads in (1) and (2) denote typical conical basal part of some processes.

Holotype

IGCAGS–NPIII–280, reposited at Institute of Geology, Chinese Academy of Geological Sciences, from the upper Member III of the Ediacaran Doushantuo Formation at Niuping section in the Yangtze Gorges area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 68.1).

Description and measurements

Vesicle medium-sized to large, oval but originally spheroidal. Processes biform, with a conical or slightly inflated basal expansion supporting a thin and cylindrical apical spine. Processes evenly distributed and basally separated. Vesicle diameter of three specimens 182–194 μm (mean = 187 μm), and a larger specimen about 262 μm in vesicle diameter (Fig. 22.1, 22.2); process length 39.5–75.2 μm (N = 5; mean = 53.4 μm, SD = 2.6 μm) or 21.0–41.4% of vesicle diameter (N = 4; mean = 28.3%; SD = 9.3%), basal width 21.2–31.5 μm (N = 5; mean = 26.8 μm, SD = 3.8 μm); process basal expansion length 16.3–22.9 μm (N = 5; mean = 19.6 μm, SD = 3.0 μm) or 30.1–56.3% of vesicle diameter (N = 5; mean = 38.6%; SD = 10.8%); about 2–3 processes per 100 μm of vesicle periphery.

Material

Two specimens illustrated in Figure 22.1–22.3 (the specimen in Fig. 22.1, 22.2 also was illustrated in Ouyang et al., Reference Ouyang, Guan, Zhou and Xiao2017, fig. 9J), two specimens illustrated in Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017, fig. 9I, L, M), and one additional specimen.

Remarks

Both Mengeosphaera? cuspidata Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, and M. triangularis have been transferred to Tanarium (Liu and Moczydłowska, Reference Liu and Moczydłowska2019), although both are characterized by biform processes with a clearly defined inflection. Two of the specimens described here were originally illustrated as M.? cuspidata by Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017, fig. 9I–K), and reassigned to T. triangulare by Liu and Moczydłowska (Reference Liu and Moczydłowska2019) without justification, but then again considered to be T. cuspidatum (Shang et al., Reference Shang, Liu and Moczydłowska2019; Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022). These specimens have processes that seem to exhibit a deflated base and thus resemble T. cuspidatum, but a re-examination of them has convinced us that most basal expansions are conical or slightly inflated with an inflection point (see red arrowheads in Fig. 22.1, 22.2). Thus, we follow Liu and Moczydłowska (Reference Liu and Moczydłowska2019) and identify the two specimens illustrated in Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017, fig. 9I–K) as T. triangulare. One specimen illustrated as Mengeosphaera chadianensis in Ouyang et al. (Reference Ouyang, Guan, Zhou and Xiao2017, fig. 9L–M) is similar to the two specimens mentioned above in process shape, size, and arrangement, and is also re-assigned to T. triangulare.

Holotype

PMU-Sib.4-J/30/3, reposited at Uppsala University, from the Ediacaran Khamaka Formation, Nepa-Botuoba region, Yakutia, Siberia (Moczydłowska et al., Reference Moczydłowska, Vidal and Rudavskaya1993, p. 517, text-fig. 15A, B, D).

Description and measurements

Vesicle spheroidal, medium-sized, bearing basally connected, large conical processes. Vesicle diameter about 113 μm, process length about 32.0 μm (28.3% of vesicle diameter), and basal width about 32.4 μm (28.7% of vesicle diameter), with 1–2 processes per 100 μm of vesicle periphery.

Material

One specimen illustrated in Figure 22.4.

Remarks

Among all species of Tanarium, T. tuberosum is unique in its proportionally large conical processes with the broadest base. The specimen described here is larger than but otherwise similar to the holotype of T. tuberosum in process morphology and proportional size. For comparison, process length is about 22.8% of vesicle diameter, process basal width is about 20.9% of vesicle diameter, and length to basal width ratio is about 1.1 in the holotype, based on measurements taken from Moczydłowska et al. (Reference Moczydłowska, Vidal and Rudavskaya1993, text-fig. 15A, B, D). Our specimen differs from the holotype and some other published specimens of T. tuberosum in its relatively high process density; however, similar process density is also reported in a few specimens identified as T. tuberosum (e.g., Liu and Moczydłowska, Reference Liu and Moczydłowska2019, fig. 86A, B). We thus identified our specimen as T. tuberosum.

Type species

Tianzhushania spinosa Yin and Li, Reference Yin and Li1978, emend. Yin in Yin and Liu, Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988.

Other species

Tianzhushania polysiphonia Yin in Yin and Liu, Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988; T. rara Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014.

Tianzhushania spinosa Yin and Li, Reference Yin and Li1978, emend. Yin in Yin and Liu, Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988
 Figure 23

Reference Yin and Li1978

Tianzhushania spinosa Yin and Li, p. 95, pl. 8, fig. 13.

Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu, p. 178, pl. 10, figs. 1–4.

Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988

Tianzhushania tubaeformis Yin in Yin and Liu, p. 178, pl. 9, figs. 8, 9.

Reference Yin1990

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin, pl. I, figs. 3, 4.

Reference Yin and Gao1995

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin and Gao, pl. II, fig. 10.

Reference Yin1996

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin, p. 326, pl. I, fig. 1.

Reference Zhang, Yin, Xiao and Knoll1998

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Zhang et al., p. 40, fig. 13.1, 13.4.

non Reference Zhang, Yin, Xiao and Knoll1998

Tianzhushania spinosa Yin in Yin and Li; Zhang et al., p. 40, fig. 13.2, 13.3.

Reference Yin1999

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin, p. 12, pl. 4, figs. 1–3.

Reference Yin2001

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin, pl. I, fig. 8.

Reference Yin, Gao and Xing2001

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin et al., p. 500, pl. I, figs. 1–4, pl. II, figs. 1, 2, 6.

non Reference Yin2001

Tianzhushania spinosa Yin in Yin and Li, emend. Yin in Yin and Liu; Yin, pl. II, figs. 1, 2.

non Reference Yin2001

Tianzhushania spinosa Yin in Yin and Li, emend. Yin in Yin and Liu; Yin et al., pl. II, figs. 3–5.

Reference Yin, Gao and Yue2003

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin et al., pl, I, figs, 5, 6.

Reference Yin, Bengtson and Yue2004

Tianzhushania spinosa Yin and Li; Yin et al., figs. 2A, 5D.

Reference Yin, Bengtson and Yue2004

Tianzhushania sp.; Yin et al., fig. 3A.

non Reference Yin, Bengtson and Yue2004

Tianzhushania spinosa Yin in Yin and Li; Yin et al., fig. 3B.

Reference Yin, Zhu, Knoll, Yuan, Zhang and Hu2007

Tianzhushania spinosa; Yin et al., fig. 1c–l.

Reference Zhou, Xie, McFadden, Xiao and Yuan2007

Tianzhushania spinosa; Zhou et al., fig. 4A.

Reference Yin, Zhou and Yuan2008

Tianzhushania conferta Yin et al., p. 138, pl. I, figs. 11–13.

Reference Yin, Zhou and Yuan2008

Tianzhushania fissura Yin et al., p. 138, pl. I, figs. 2–10.

non Reference Shukla, Mathur, Babu and Srivastava2008

Tianzhushania spinosa; Shukla et al., p. 374, pl. III, figs. 1, 2.

Reference Liu, Yin, Gao, Tang and Chen2009

Tianzhushania spinosa; Liu et al., fig. 2o–q.

Reference Yin, Liu, Chen, Tang, Gao and Wang2009a

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Yin et al., pl. I, figs. 1, 8.

Reference Chen, Yin, Liu, Gao, Tang and Wang2010

Tianzhushania spinosa; Chen et al., fig. 2.13, 2.17.

Reference Yin, Wang, Yuan and Zhou2011

Tianzhushania spinosa; C. Yin et al., fig. 4a, b.

Reference Xiao, McFadden, Peek, Kaufman, Zhou, Jiang and Hu2012

Tianzhushania spinosa; Xiao et al., fig. 4C–H.

Reference Liu, Yin, Chen, Tang and Gao2013

Tianzhushania spinosa; Liu et al., fig. 10A.

Reference Zeng, Chen, Li, Zhou, Zhang and Peng2013

Tianzhushania spinosa; Zeng et al., fig. 3.2.

Reference Liu, Yin, Chen, Tang and Gao2013

Tianzhushania conferta Yin et al.; Liu et al., fig. 10E.

Reference Liu, Yin, Chen, Tang and Gao2013

Tianzhushania fissura Yin et al.; Liu et al., fig. 10D.

Reference Zeng, Chen, Li, Zhou, Zhang and Peng2013

Tianzhushania fissura; Zeng et al., fig. 3.1.

Reference Zeng, Chen, Li, Zhou, Zhang and Peng2013

Tianzhushania sp.; Zeng et al., fig. 3.3.

Reference Xiao, Zhou, Liu, Wang and Yuan2014

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Xiao et al., p. 56.

Reference Liu, Chen, Zhu, Li, Yin and Shang2014b

Tianzhushania spinosa; Liu et al., fig. 7D–F.

Reference Ouyang, Zhou, Guan and Wang2015

Tianzhushania spinosa Yin and Li, emend. Yin in Yin and Liu; Ouyang et al., p. 219, pl. III, figs. 1–6.

Reference Joshi and Tiwari2016

Tianzhushania spinosa; Joshi and Tiwari, p. 332, fig. 4B–E.

Reference Hawkins, Xiao, Jiang, Wang and Shi2017

Tianzhushania spinosa; Hawkins et al., fig. 6A, B.

non Reference Hawkins, Xiao, Jiang, Wang and Shi2017

possibly Tianzhushania spinosa; Hawkins et al., fig. 7A, B.

Reference Ouyang, Zhou, Xiao, Chen and Shao2019

Tianzhushania spinosa; Ouyang et al., fig. 11A, B.

Reference Yang, Pang, Chen, Zhong and Yang2020

Tianzhushania sp.; Yang et al., p. 9, fig. 2P, Q.

Reference Liu, Qi, Fan, Guo and Pei2021

Tianzhushania spinosa; Liu et al., fig. 5.1.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Tianzhushania spinosa Yin in Yin and Li, emend. Yin in Yin and Liu; Ouyang et al., fig. 21A–L.

non Reference Sharma, Shukla and Sergeev2021

Tianzhushania spinosa Yin and Li; Sharma et al., fig. 9A, D.

Reference Joshi, Mishra and Tiwari2022

Tianzhushania spinosa; Joshi et al., fig. 4d (mistakenly presented as 4c in figure caption; fig. 4c is T. polysiphonia).

Figure 23. Tianzhushania spinosa Yin and Li, Reference Yin and Li1978, emend. Yin in Yin and Liu, Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988. (1–6) PB202061, thin section 21LHK-1-10, O41/4; circled 2 and 6 in (1) mark the areas magnified in (2) and (6), respectively; circled 3 in (2) marks the area magnified in (3); circled 4 in (2) marks the same area magnified in (4) and (5) at different focal levels. Red arrowheads denote hollow cylindrical processes embedded in multilaminate membrane; blue arrowheads denote poorly preserved multilaminate membrane.

Holotype

Tian R29 X150, reposited at NIGPAS, from the Ediacaran Doushantuo Formation at Tianzhushan in Changyang area, Hubei Province, South China (Yin and Li, Reference Yin and Li1978, pl. 8, fig. 13).

Description and measurements

Vesicle large, strongly deformed, originally spheroidal. Processes hollow and cylindrical (Fig. 23.2, 23.4, 23.5), evenly distributed, penetrating a multilaminate outer membrane (Fig. 23.3, 23.6) that surrounds the vesicle wall. Vesicle diameter unmeasurable due to deformation. Processes about 61.6 μm long and 1.4 μm wide, with about six processes per 100 μm of vesicle periphery. The thickness of the multilaminate outer membrane was not measured because it is likely cut obliquely in the thin section but is estimated to be similar to the length of cylindrical processes.

Material

One illustrated specimen (Fig. 23).

Remarks

Although poorly preserved, the specimen does show hollow cylindrical processes penetrating a multilaminate membrane, which are features diagnostic of Tianzhushania. The long, evenly and densely arranged processes identify this specimen to T. spinosa, which is different from the clustered distribution of processes in T. polysiphonia and the short and sparse processes in T. rara. Since Ouyang et al. (Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021) reassigned the possible T. spinosa specimen reported from the Siduping section by Hawkins et al. (Reference Hawkins, Xiao, Jiang, Wang and Shi2017, fig. 7A, B) to Crassimembrana multitunica Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021, the specimen reported here represents the only known occurrence of Tianzhushania from the Doushantuo Formation in basinal facies or deep-water settings.

Three specimens identified as Tianzhushania sp. from the Weng'an, Yangtze Gorges, and Baokang areas (Yin et al., Reference Yin, Bengtson and Yue2004; Zeng et al., Reference Zeng, Chen, Li, Zhou, Zhang and Peng2013; Yang et al., Reference Yang, Pang, Chen, Zhong and Yang2020) all bear numerous hollow cylindrical processes that are embedded in a thick multilaminate layer and evenly distributed, and are here reassigned to T. spinosa. The specimen identified as T. spinosa from the Krol'A Formation in northern India (Sharma et al., Reference Sharma, Shukla and Sergeev2021, fig. 9A, D) has small conical processes and thus should be excluded from Tianzhushania. Considering its small and densely distributed processes, that specimen may belong to Knollisphaeridium, possibly K. coniformum, as noted in Xiao et al. (Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022).

Type species

Trachyhystrichosphaera aimika Hermann in Timofeev et al., Reference Timofeev, Hermann and Mikhailova1976.

Other species

Trachyhystrichosphaera botula Tang et al., Reference Tang, Pang, Xiao, Yuan, Ou and Wan2013; T. polaris Butterfield in Butterfield et al., Reference Butterfield, Knoll and Swett1994.

Trachyhystrichosphaera? sp.
 Figure 24

non Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988

Trachyhystrichosphaera sp.; Yin and Liu, p. 177, p. 180, pl. 11, figs. 3, 4.

non Reference Knoll and Walter1992

?Trachyhystrichosphaera sp.; Knoll, p. 770, pl. 4, fig. 1, pl. 5, figs. 1, 2.

non Reference Yin1999

?Trachyhystrichosphaera sp.; Yin, p. 14, pl. 3, fig. 3.

?Reference Nagovitsin, Faizullin and Yakshin2004

Trachyhystrichosphaera aff. aimica Hermann, 1976 [sic]; Nagovitsin et al., p. 14, pl. I, fig. 10.

Figure 24. Trachyhystrichosphaera? sp. (1–8) PB202062, thin section 19CW-6-16, M40/3; circled 2–5 and 8 in (1) mark areas magnified in (2–5) and (8), respectively; circled 6 in (1) marks the same area magnified in (6) and (7) at different focal levels to show different processes. Scale bar in (5) also applies to (2–4, 6–8). Red arrowheads denote cylindrical processes, yellow arrowheads denote conical processes, blue arrowheads denote outer membrane.

Description and measurements

Vesicle small, spheroidal or ovoidal, with sparsely and irregularly distributed hollow processes. Processes bimorphic, with larger conical and smaller cylindrical ones. Vesicle diameter about 248 μm; conical processes 6.2–14.8 μm in length with an average of 10.7 μm, or 2.5–6.0% of vesicle diameter with an average of 4.3%, and 4.4–11.1 μm in basal width with an average of 7.6 μm; cylindrical processes 5.3–8.1 μm in length with an average of 6.9 μm, or 2.1–3.3% of vesicle diameter with an average of 2.8%, and 0.9–1.6 μm (with an average of 1.3 μm in width). An outer membrane can be found on top of some conical (Fig. 24.2–24.4) and cylindrical (Fig. 24.5–24.8) processes.

Material

A single fairly well-preserved specimen (Fig. 24).

Remarks

The illustrated specimen is tentatively assigned to Trachyhystrichosphaera based on its bimorphic processes and outer membrane. Some other genera are also characterized by bimorphic or heteromorphic processes, including Alicesphaeridium, Asseserium, Bispinosphaera, Distosphaera, Duospinosphaera, Sinosphaera, and Verrucosphaera. Among them, Alicesphaeridium, Bispinosphaera, Distosphaera, Duospinosphaera, Sinosphaera, and Verrucosphaera are all characterized by their abundant, densely, and somewhat evenly distributed processes that cover the entire vesicle surface. Asseserium diversum Nagovitsin and Moczydłowska in Moczydłowska and Nagovitsin, Reference Moczydłowska and Nagovitsin2012, bears heteromorphic and irregularly distributed hollow processes (Moczydłowska and Nagovitsin, Reference Moczydłowska and Nagovitsin2012), and its process density is similar to the illustrated specimen. However, compared with Asseserium, which has a small to medium-sized vesicle bearing processes whose length is 10–40% of the vesicle diameter, the illustrated specimen has a vesicle several times larger and thus proportionally shorter processes. In addition, none of the above-mentioned bimorphic or heteromorphic taxa have an outer membrane, which is observed in the illustrated specimen (blue arrowheads in Fig. 24.3, 24.5–24.8), and diagnostic of Trachyhystrichosphaera (Tang et al., Reference Tang, Pang, Xiao, Yuan, Ou and Wan2013).

Trachyhystrichosphaera is a typical Tonian genus (Pang et al., Reference Pang, Tang, Wan and Yuan2020), and has been only infrequently reported, mostly as open nomenclature, from Ediacaran strata (Knoll, Reference Knoll1992; Faizullin, Reference Faizullin1998; Nagovitsin et al., Reference Nagovitsin, Faizullin and Yakshin2004). Several previously published specimens of Trachyhystrichosphaera lack the diagnostic features of and thus should be excluded from this genus, including Trachyhystrichosphaera sp. in Yin and Liu (Reference Yin, Liu, Zhao, Xing, Ding, Liu, Zhao, Zhang, Meng, Yin, Ning and Han1988, p. 177, pl. 11, figs. 3, 4), ?Trachyhystrichosphaera sp. in Knoll (Reference Knoll1992, p. 770, pl. 4, fig. 1, pl. 5, figs. 1, 2), ?Trachyhystrichosphaera sp. in Yin (Reference Yin1999, p. 14, pl. 3, fig. 3), Trachyhystrichosphaera aff. aimica [sic] in Nagovitsin et al. (Reference Nagovitsin, Faizullin and Yakshin2004, pl. I, figs. 7 and 11 only), and T. aimika in Shukla et al. (Reference Shukla, Mathur, Babu and Srivastava2008, p. 374, pl. 2, fig. 1). The specimen identified as Trachyhystrichosphaera sp. in Faizullin (Reference Faizullin1998, pl. I, fig. 16) was poorly illustrated and a re-examination of the specimen is required to assess its taxonomic identification. One of the three specimens identified as Trachyhystrichosphaera aff. aimica [sic] extracted from shales of the Ediacaran Ura Formation in Siberia (Nagovitsin et al., Reference Nagovitsin, Faizullin and Yakshin2004, pl. I, fig. 10) contains an outer layer enveloping short, hollow, and sparsely distributed processes, resembling the specimen illustrated here, and fits the diagnosis of Trachyhystrichosphaera. However, these two possible occurrences of Ediacaran Trachyhystrichosphaera are each represented by a single specimen, and may represent morphological variations of other acanthomorphs such as Tianzhushania rara. Therefore, we place the illustrated specimen in an open nomenclature.

Type species

Urasphaera capitalis Nagovitsin and Moczydłowska in Moczydłowska and Nagovitsin, Reference Moczydłowska and Nagovitsin2012.

Other species

Urasphaera fungiformis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a; U. nupta Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a.

Urasphaera fungiformis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a
 Figure 25

Reference Liu, Yin, Chen, Tang and Gao2013

Gyalosphaeridium pulchrum Zang in Zang and Walter, Reference Zang and Walter1992; Liu et al., fig. 13G.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Urasphaera fungiformis Liu et al., p. 119, figs. 87, 88, 89.1.

Reference Nie, Liu and Dong2017

Urasphaera fungiformis Liu et al.; Nie et al., p. 380, fig. 9.

Reference Ouyang, Guan, Zhou and Xiao2017

Urasphaera fungiformis; Ouyang et al., fig. 8G–J (the specimen described here and illustrated in Fig. 26).

Reference Ye, Li, Tong, An, Hu and Xiao2022

Urasphaera fungiformis Liu et al.; Ye et al., fig. 48A–C.

Figure 25. Urasphaera fungiformis Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a. (1–3) PB202063, thin section 14HA-115-1, N50; circled 2 in (1) marks the same area magnified in (2) and (3) at different focal levels to show different processes.

Figure 26. Verrucosphaera? undulata new species. (1–5) Holotype, PB202064, thin section 21DC-6-1, H44; circled 2 in (1) marks the same area magnified in (2) and (3) at different focal levels to show different processes; circled 4 in (1) marks the same area magnified in (4) and (5) at different focal levels to show different processes; (6–8) PB202065, thin section 21DC-5-4, S47; circled 7 and 8 in (6) mark areas magnified in (7) and (8), respectively. Red arrowheads denote thin cylindrical processes on top of thick conical processes.

Holotype

IGCAGS-NPIII-482, thin section NPIII13-3-5, Nikon 80i coordinates 23.8×111, England Finder coordinates E23/4, reposited at the Institute of Geology, Chinese Academy of Geological Science, from the Ediacaran Doushantuo Formation at the Niuping section in Yichang area, Hubei Province, South China (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, fig. 87.1–87.4).

Description and measurements

Vesicle large, spheroidal, bearing evenly distributed processes. Processes begin with a wide and deflated base that tapers to form a waist and then expands distally to form a truncated terminal end. Vesicle diameter about 400 μm, with 1–2 processes per 100 μm of vesicle periphery. Process length about 39.3 μm and 9.8% of vesicle diameter, basal width about 27.2 μm, terminal width about 9.3 μm, minimum width of process (waist width) about 3.2 μm.

Material

One well-preserved specimen (Fig. 25).

Remarks

The specimen at hand is larger than specimens of Urasphaera fungiformis from the type locality at the Niuping section in the Yangtze Gorges area of Hubei Province (Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a), but comparable to those from the Shennongjia area reported by Ye et al. (Reference Ye, Li, Tong, An, Hu and Xiao2022, fig. 48A–C). Nonetheless, this specimen resembles those from the Yangtze Gorges area in the moderate number of proportionally short processes with a broadened base, features that distinguish U. fungiformis from U. capitalis and U. nupta. The small distal expansion may not be captured in all processes of Urasphaera if the processes are cut obliquely in the thin section, thus some processes may appear conical in shape.

Type species

Verrucosphaera minima Liu and Moczydłowska, Reference Liu and Moczydłowska2019.

Other species

Verrucosphaera? undulata n. sp.

Verrucosphaera? undulata new species
 Figures 26–28

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

?Verrucosphaera sp.; Shi et al., fig. 10A–F (including the type specimen in fig. 10A, B, D).

Figure 27. Verrucosphaera? undulata new species. (1–4) PB202066, thin section 21DC-5-4, P41/2; circled 2–4 in (1) mark areas magnified in (2–4), respectively; (5–7) PB202067, thin section 21DC-5-4, T32/4; circled 6 and 7 in (5) mark areas magnified in (6) and (7), respectively; (8–10) PB202068, thin section 21DC-5-4, L43/3; circled 9 and 10 in (8) mark areas magnified in (9) and (10), respectively. Red arrowheads denote thin cylindrical processes on top of thick conical processes.

Figure 28. Sketch of Verrucosphaera? undulata new species.

Holotype

PB202064, thin section 21DC-6-1, ZEISS Scope A1 coordinates 8×92, England Finder coordinates H44, illustrated in Figure 26.1–26.5, reposited at NIGPAS, from Doushantuo Formation at the Caojunba section in Shimen area, Hunan Province, South China.

Diagnosis

Vesicle medium-sized, spheroidal or ovoidal, bearing two sets of bimorphic processes: a set of large conical processes supporting a set of thin filamentous processes. The large processes are hollow, obtusely conical, basally connected or separated, terminally rounded or truncated, irregularly distributed, and variable in both length and basal width. The thin filamentous processes are cylindrical, more or less uniform in length and thickness, densely arranged but basally separated, and evenly distributed on both the vesicle wall and the large processes. The large conical and thin filamentous processes are comparable in length, accounting for about 5% of vesicle diameter.

Description and measurements

Holotype: vesicle diameter 172 μm; large processes 4.8 μm in length (2.8% of vesicle diameter) and 7.9 μm in basal width; thin processes 4.9 μm in length (2.8% of vesicle diameter) and 0.2 μm in diameter, 27 processes per 100 μm of vesicle periphery. Other specimens: vesicle diameter 126–192 μm (N = 30, mean = 162 μm, SD = 16 μm); large process length 3.8–18.7 μm (N = 25, mean = 8.2 μm, SD = 3.4 μm) or 2.3–10.0% of vesicle diameter (N = 25, mean = 5.1%, SD = 1.9%), process basal width 6.7–44.8 μm (N = 23, mean = 18.5 μm, SD = 9.4 μm); thin process length 2.8–8.7 μm (N = 24, mean = 5.6 μm, SD = 1.3 μm) or 1.7–5.6% of vesicle diameter (N = 24, mean = 3.5%, SD = 0.9%), process width 0.2–0.6 μm (N = 22, mean = 0.3 μm, SD = 0.1 μm), 23–47 processes per 100 μm of vesicle periphery.

Etymology

From Latin undulatus, wavy, with reference to the wavy profile of the vesicle wall as viewed in thin sections due to the irregular arrangement of large processes which are obtusely conical in shape.

Material

Five illustrated specimens (Figs. 26, 27) and 26 additional specimens.

Remarks

There are several other taxa that are characterized by bimorphic processes, with a set of large hollow processes and another set of thin cylindrical processes. These taxa, including Bispinosphaera, Distosphaera, and Duospinosphaera, differ from Verrucosphaera in the spatial relationship between the two set of processes: the thin processes in Bispinosphaera, Distosphaera, and Duospinosphaera are initiated from either the inner or outer surface of the vesicle wall and they are not found on top of the large processes. Verrucosphaera? undulata n. sp. is different from V. minima in that the thin processes are only found on top of the large processes in the latter species, but they can be on top of both the large processes and the vesicle wall in the former species. Additionally, the large processes are more or less conical in V.? undulata n. sp. but hemispherical in V. minima. Considering these similarities and differences, V.? undulata n. sp. is tentatively placed in the genus Verrucosphaera, pending an emendation of the genus diagnosis.

Type species

Weissiella grandistella Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009.

Other species

Weissiella brevis Xiao et al., Reference Xiao, Zhou, Liu, Wang and Yuan2014, emend. Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021; Weissiella concentrica Ye et al., Reference Ye, Li, Tong, An, Hu and Xiao2022.

Remarks

The genus Weissiella is characterized by hollow and internally septate processes. Several other Ediacaran acanthomorph taxa are also known for their hollow and internally decorated processes. These internal decorations include either transverse septa (as in Bispinosphaera peregrina Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a, Weissiella, and Yushengia ramispina Liu et al., Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a) or domal structures (as in Mengeosphaera matryoshkaformis). Among these taxa, Weissiella has the widest paleogeographic distribution and the greatest morphological variation. Thus far, three species of Weissiella have been recognized (W. grandistella, W. brevis, W. concentrica), differentiated from each other by their process morphologies and the presence of an outer wall. In addition to these three species, Ouyang et al. (Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021) proposed the assignment of all silicified Weissiella specimens from the Doushantuo Formation with large conical processes to Weissiella cf. W. grandistella, emphasizing both their morphological similarities to and difference from W. grandistella specimens from the type locality. Two unnamed species of Weissiella (Ye et al., Reference Ye, Tong, An, Tian, Zhao and Zhu2015, pl. I, figs. 15–19, and Ouyang et al., Reference Ouyang, Zhou, Xiao, Chen and Shao2019, fig. 10E–G) were reassigned to W. brevis (Xiao et al., Reference Xiao, Jiang, Ye, Ouyang, Banerjee, Singh, Muscente, Zhou and Hughes2022); the processes in the former (Ye et al., Reference Ye, Tong, An, Tian, Zhao and Zhu2015) are irregularly shaped with occasional branches, whereas those in the latter (Ouyang et al., Reference Ouyang, Zhou, Xiao, Chen and Shao2019) are likely biform, both of which are different from W. brevis from the type locality but considered as representing intraspecific variations of W. brevis. The existence of transverse septa or cross-walls in the processes of Weissiella and other taxa raises the interesting question about their functions, a topic worthy of further investigation in the future.

Weissiella cf. W. grandistella Vorob'eva, Sergeev, and Knoll, Reference Vorob'eva, Sergeev and Knoll2009
 Figure 29

Reference Liu, Yin, Chen, Tang and Gao2013

Weissiella grandistella; Liu et al., fig. 13E.

Reference Liu, Xiao, Yin, Chen, Zhou and Li2014a

Weissiella grandistella Vorob'eva et al.; Liu et al., p. 128, figs. 94, 95.

Reference Liu, Chen, Zhu, Li, Yin and Shang2014b

Weissiella grandistella; Liu et al., fig. 9E.

non Reference Shukla and Tiwari2014

Weissiella cf. W. grandistella; Shukla and Tiwari, p. 219, fig. 8A–E.

Reference Liu and Moczydłowska2019

Weissiella grandistella Vorob'eva et al.; Liu and Moczydłowska, p. 163, figs. 91F, G, 92.

Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021

Weissiella cf. W. grandistella; Ouyang et al., fig. 24A–H.

Reference Shi, Ouyang, Zhou, Xiao, Chen and Guan2022

Weissiella cf. W. grandistella; Shi et al., fig. 10G–I (the specimen described here and illustrated in Fig. 29).

Reference Ye, Li, Tong, An, Hu and Xiao2022

Weissiella cf. grandistella Vorob'eva et al.; Ye et al., fig. 49D–F.

Figure 29. Weissiella cf. W. grandistella. (1–7) PB202069, thin section 21DC-2-30, T35; circled 2–4 in (1) mark areas magnified in (2–4), respectively; red arrowheads denote cross-walls in the processes; (5–7) cross-polarized light microscopic photographs of (1); circled 6 in (2) and circled 7 in (3) showing areas in (6) and (7), respectively; recrystallized micro-quartz indicated by yellow arrowheads; scale bar in (6) also applies to (7).

Description and measurements

Vesicle medium-sized, spheroidal, bearing a modest number of large conical processes evenly distributed on the vesicle surface. Processes hollow but each contains about two thin cross-walls or transverse septa that divide the process into several compartments (red arrowheads in Fig. 29.2–29.4). Cross-walls occur near the base of each process. Vesicle diameter about 114 μm, maximum measurable length of processes 45.0 μm (or 39.6% of vesicle diameter), process basal width 23.4 μm, about 3 processes per 100 μm of vesicle periphery.

Material

One well-preserved specimen (Fig. 29).

Remarks

As for specimens identified as Weissiella cf. W. grandistella from the Doushantuo Formation in Yangtze Gorges area, the specimen described here from the Caojunba section is also much smaller than W. grandistella from its type locality and is placed in an open nomenclature (see Ouyang et al., Reference Ouyang, Zhou, Xiao, Guan, Chen, Yuan and Sun2021, for a detailed comparison among W. grandistella, W. brevis, and permineralized Doushantuo acritarchs identified as Weissiella cf. W. grandistella). One distinctive feature of this specimen is that the cross-walls occur near the base of the processes. Examination under polarized light microscopy (e.g., Fig. 29.5–29.7) indicates that the lack of cross-walls in the distal portion of processes is not a taphonomic artifact related to recrystallization and may thus reflect intraspecific variation.

All specimens of Weissiella cf. W. grandistella from the Doushantuo Formation in South China are morphologically similar and may constitute a new species of Weissiella. However, except for their smaller size, they are otherwise similar to W. grandistella, which led Liu and Moczydłowska (Reference Liu and Moczydłowska2019) to assign them to W. grandistella. Current morphological data are not sufficient to conclusively resolve this issue, and these specimens are here treated as an open nomenclature.