The trilobite faunas that occur with the Steptoean Positive Isotope Carbon Excursion (SPICE) at Smithfield Canyon, Utah, have been reported, but not illustrated. Given the importance of the SPICE at this section for international correlations, the trilobites from new collections from the upper Nounan Dolomite to lower St. Charles Formation at Smithfield Canyon are reported herein and integrated with the previously reported taxa. Trilobite assemblages indicate that the upper Cedaria to the Ellipsocephaloides biozones (Miaolingian Series, Guzhangian Stage to Furongian Series, Jiangshanian Stage) are present stratigraphically below or above the SPICE.

Some of the taxa reported herein may represent new species, but they are not represented by well-enough preserved specimens and are left in open nomenclature. However, Kingstonia smithfieldensis n. sp. and Bromella utahensis n. sp. are named on the basis of common and well-preserved specimens.

New carbon isotope data from Smithfield Canyon from an overlapping section of the lower St. Charles Formation, that add to the overall shape of the SPICE curve, are presented. The new δ13C values above the Elvinia Biozone range from –0.36‰ to +1.5‰, confirming that the SPICE concludes within the Elvinia Biozone.

UUID: http://zoobank.org/ad4fd372-8da4-4caa-98ed-ea82700cca60

Decimeter-scale, elongate, fossil fronds from the Ediacara Range in South Australia were formally described as Rangea longa Glaessner and Wade, 1966, but the disparate nature of documented specimens has hindered their inclusion in global syntheses and has resulted in these fossils being assigned to at least five different genera in two different clades since their discovery. Detailed study of the type material from the Ediacara Range and the few specimens subsequently collected elsewhere in the Flinders Ranges reaffirms that these specimens represent a single species, with the apparent morphological variation between specimens entirely taphonomic and reflecting the obverse and reverse surfaces of these fronds coupled with the orientation of the frond axis and petaloids at different angles relative to the sea bottom on which they were preserved. The preserved architecture of these fronds constitutes three orders of branching microstructure that are strictly orthogonal to immediately higher and lower orders. This implies affinities with the arboreomorphs, but representing a new frond genus herein named Akrophyllas. Akrophyllas n. gen. differs from all other Ediacaran fronds in exhibiting a stalk that is visible only on one side of the frond and is internal to the other side where the first-order branches instead meet at a zigzag axial trace. Akrophyllas n. gen. was attached to a bulbous holdfast on the sea bottom, and evidence for current scours that formed in the lee of the fronds and for a strong current alignment of felled fronds with depositional overlap of adjacent fronds imply an upright, epibenthic lifestyle for Akrophyllas longa new combination.

UUID: http://zoobank.org/86e26477-7b1e-45da-870c-1b5d28fc510c

A new genus and species of arachnid (Chelicerata: Arachnida), Douglassarachne acanthopoda n. gen. n. sp., is described from the late Carboniferous (Moscovian) Coal Measures of the Mazon Creek Lagerstätte, Illinois, USA. This is a unique animal with distinctive large spines on the legs. It has a subovate body, a segmented opisthosoma, and a terminal anal tubercle. The legs are robust and appear to have been similar in construction throughout the limb series, with heavy spination of the preserved proximal podomeres. The mouthparts and coxo-sternal region are equivocal. The preserved character combination does not permit easy referral to any known arachnid order, living or extinct, thus the new fossil in placed as Arachnida/Pantetrapulmonata incertae sedis. It contributes to an emerging pattern of disparate body plans among late Carboniferous arachnids, ranging from anatomically modern members of living orders through to extinct taxa, such as the present fossil, whose phylogenetic position remains unresolved.

UUID: http://zoobank.org/b70f5f95-9c8b-4389-bee5-b6031bff2ee2

Natural history museums house numerous previously undescribed species and unknown information hidden in their collections. We describe lower Carboniferous slit-bearing gastropods (order Pleurotomariida, subclass Vetigastropoda; and family Goniasmatidae, subclass Caenogastropoda) from previously unreported gastropod collections made by Jane Longstaff (Jane Donald), one of the pioneering paleontologists of Paleozoic gastropods in the late nineteenth and early twentieth centuries. The gastropods were collected from the Lower Limestone Formation (Visean, Brigantian) near Dalry, Ayrshire, Scotland. The collection consists largely of microgastropods, many of which are unusually well-preserved including delicate ornament and protoconchs (larval shells). Three new pleurotomariidan species are described—Biarmeaspira heidelbergerae new species, Neilsonia seussae new species, Tapinotomaria longstaffae new species—in addition to seven species belonging to Borestus Thomas, 1940, Stegocoelia (Stegocoelia) Donald, 1889, Stegocoelia (Hypergonia) Donald, 1892, Donaldospira Batten, 1966, and Platyzona Knight, 1945. The caenogastropod-type protoconch is documented for the first time in Hypergonia, which is therefore placed in Goniasmatidae. The new data confirm that Neilsonia Thomas, 1940 (type genus of Neilsoniinae) belongs to Pleurotomariida and is distinct from the morphologically convergent Peruvispira Chronic, 1949 (Goniasmatidae). The selenizone morphology is identical in Biarmeaspira Mazaev, 2006 and Baylea de Koninck, 1883 during their early ontogeny, and Biarmeaspira develops an angulation on the selenizone (the diagnostic feature) in late ontogeny. This corroborates earlier suggestions that Biarmeaspira evolved from Baylea. Biarmeaspira heidelbergerae n. sp. is the first Carboniferous record of Biarmeaspira, which was previously only known from the Permian. The angulated selenizone evidently evolved several times in Pleurotomariida and the repeated appearance of this character in different groups (e.g., Phymatopleuridae, Eotomariidae, Pleurotomariidae) needs further studies using phylogenetic methods.

UUID: http://zoobank.org/92ae9a99-5774-4ee9-bf5d-9a9319494ef6

We analyzed the ontogenetic trajectories of conch morphology and septal spacing between successive chambers in Cretaceous ammonoids (suborders Perisphinctina and Ancyloceratina) collected from southern India, Madagascar, and Japan. All examined species, except for the family Collignoniceratidae, exhibited similar characteristics during early ontogeny. The common ontogenetic trajectories of septal spacing show a cycle comprising an increase and a subsequent decrease in septal spacing during early ontogeny. The conch diameters at the end of the cycle were estimated to be 1–4 mm. The conch shape (aperture height and whorl expansion rate) covariably changed at this conch diameter. Such covariable changes are commonly recognized in the suborders Perisphinctina and Ancyloceratina. The similarity in the ontogenetic trajectories of conch morphology implies a closer phylogenetic relationship between these suborders compared to Lytoceratina or Phylloceratina.

The terminal Ediacaran Period is signaled worldwide by the first appearance of skeletonizing tubular metazoan fossils, e.g., Cloudina Germs, 1972 and Sinotubulites Chen, Chen, and Qian, 1981. Although recent efforts have focused on evaluating the taxic composition and preservation of such assemblages from the southwestern United States, comparable forms reported in the 1980s from Mexico remain to be re-examined. Here, we reassess the latest Ediacaran skeletal materials from the La Ciénega Formation of the Caborca region in Sonora, Mexico, using a combination of analytical methods: optical microscopy of extracted fossils, thin-section petrography, scanning electron microscopy and energy dispersive X-ray spectroscopy, and X-ray tomographic microscopy. From our examination, we conclude that the La Ciénega hosts a polytaxic assemblage of latest Ediacaran tubular organisms that have been preserved through two taphonomic pathways: coarse silicification and calcareous recrystallization preserving finer details. Further, these fossils show signs that their shells might not have been inflexible or completely mineralized in vivo, and that they might also record tentatively interpreted predation traces in the form of drill holes or puncture marks. This work, along with ongoing efforts around the world, helps to provide a framework for biostratigraphic correlation and possible subdivision of the Ediacaran Period, and further shapes our view of metazoan evolution and ecology in the interval directly preceding the Cambrian explosion.

A small trilobite assemblage, including Parabolina (Neoparabolina) frequens, assignable to the Parabolina Fauna, has been recovered from the Furongian (Cambrian Stage 10) Sah Member of the Mila Formation in the Tuyeh–Darvar section, the eastern Alborz Mountains, north Iran. The assemblage includes eight genera and species; two of them, Niobella darvarensis n. sp. and Macropyge (Promacropyge) sahensis n. sp., are new to science. The incursion of a Parabolina fauna into Alborz is confined to a significant drowning event with associated dark-gray shale deposition, which most probably occurred in the lower part of the Cordylodus proavus conodont Zone. While the generic composition of the assemblage is mostly cosmopolitan with the exception of the endemic Alborsella, the occurrence of Indiligens, Macropyge (Promacropyge) sahensis n. sp., Agnostotes sp. aff. A. sulcatus, and Leiagnostus bexelli indicates faunal links with South China and Tarim. Parabolina (Neoparabolina) frequens is widespread mainly in offshore deposits from temperate Gondwana (Armorican terrane assemblage, Argentina) and Baltica of about that age.

UUID: http://zoobank.org/6b3118d0-5907-41b9-af44-cee838c5e630

A new crinoid fauna has been discovered in the Upper Ordovician (Katian) Martinsburg Formation at a small shale quarry, locally known as the ‘Shale Bank,’ on the Shawangunk Ridge in Ulster County, NY. The assemblage, which is from a relatively low energy, offshore mud-bottom environment, includes four identified species, including a new species of glyptocrinid camerate, Pycnocrinus mohonkensis n. sp., described herein. Crinoid taxa in order of increasing branch density in the assemblage include (1) the dicyclic inadunate Merocrinus curtus with irregularly isotomous and heterotomous, non-pinnulate arms and a stout cylindrical column exceeding 700 mm; (2) the disparids Cincinnaticrinus varibrachialus, with heterotomous non pinnulate arms, and Ectenocrinus simplex, with extensively branched ramulate arms and meric columns of 460–500 mm; and (3) the camerate Pycnocrinus mohonkensis n. sp., with uniserial pinnulate arms and a somewhat shorter column. Some cylindrical stems with nodose and holomeric columnals are thought to belong to unknown camerate crinoids with pinnulate arms. Filtration theory is used to model food capture in the Martinsburg crinoids. Surprisingly, even densely pinnulate camerates were able to survive in this setting, suggesting that ambient currents attained velocities exceeding 25 cm/sec even in this offshore setting. Similar assemblages were widespread in eastern Laurentia during the Late Ordovician.

UUID: http://zoobank.org/23ca31e8-f572-4520-ba1d-891e3abb950d

Successions in Oklahoma and Nevada record trilobite extinction and replacement near the Steptoean–Sunwaptan boundary in inner-shelf and outer-shelf settings, respectively. Prior to the extinctions, different trilobite biofacies occupied these environments, but faunas became similar in composition across the environmental gradient in the overlying I. “major” and Taenicephalus zones. Faunal changes in the outer shelf at the I. “major” Zone begin at a drowning unconformity that brought dark, laminated calcisiltite and silty lime mudstone above a subtidal carbonate succession. In contrast, Oklahoma shows facies continuity in a succession of tidally influenced bioclastic carbonates. Loss of genera and a dramatic abundance “spike” of Irvingella are features of the I. “major” Zone in both regions. Turnover of biofacies occurred in the succeeding Taenicephalus Zone, with both the inner and outer shelf dominated by Orygmaspis (Parabolinoides). Blooms of orthid brachiopods in shallow water settings are underappreciated signals of faunal change in the extinction interval. Although absent from the outer shelf in Nevada, orthids became abundant enough in Oklahoma to form shell beds in the lower Taenicephalus Zone, but became rare in overlying strata. Carbon isotope stratigraphy includes a modest positive δ13C excursion that peaks in the extinction interval at 1.4‰ (Oklahoma) and 2.2‰ (Nevada), which is congruent with previous reports from Utah and Wyoming. Although consistent with regional upwelling of dysoxic waters, the absence of sedimentary evidence for significant environmental change over much of the shelf is problematic. This suggests that physical environmental change acted primarily as a catalyst for cascading ecological and biogeographic effects.

This work presents a detailed taxonomic study on organic-walled microfossils from the Ediacaran Sete Lagoas Formation (Bambuí Group) at the Barreiro section in the Januária area of the São Francisco basin, Brazil. Seven species are described, including Siphonophycus robustum (Schopf, 1968), Ghoshia januarensis new species, Leiosphaeridia crassa (Naumova, 1949), Leiosphaeridia jacutica (Timofeev, 1966), Leiosphaeridia minutissima (Naumova, 1949), Leiosphaeridia tenuissima Eisenack, 1958, and Germinosphaera bispinosa Mikhailova, 1986. These taxa are recovered for the first time in the Sete Lagoas Formation. They occur abundantly in the lower portion of the studied section, but only Ghoshia januarensis is present in the upper part of the studied section, probably due to environmental or taphonomic changes. Leiosphaeridia species, particularly Leiosphaeridia minutissima, dominate the organic-walled microfossil assemblage. Although most taxa described here have long stratigraphic ranges, they are consistent with a terminal Ediacaran age as inferred from detrital zircon data and tubular fossils (e.g., Cloudina and Corumbella) from the Sete Lagoas Formation.

UUID: http://zoobank.org/7f92b900-0176-4da6-93a3-fd51edb22cbf

‘Captorhinikos’ chozaensis Olson, 1954 is a captorhinid eureptile with multiple tooth rows from the lower Permian (Cisuralian: Kungurian) Clear Fork Group of north-central Texas and the Hennessey Formation of Oklahoma. It has five maxillary and four dentary tooth rows. We re-examined the available specimens referred to ‘Captorhinikos’ chozaensis to elucidate aspects of its skeletal structure and assess its phylogenetic relationships. Our parsimony analysis confirmed previous suggestions that this taxon is not referable to the same taxon as Captorhinikos valensis Olson, 1954 (type species of the genus) and ‘Captorhinikos’ parvus Olson, 1970 and thus is placed in its own new genus, Sumidadectes. It also recovered Sumidadectes chozaensis n. comb. as the earliest-diverging moradisaurine captorhinid.

UUID: http://zoobank.org/0f89869a-1889-4d90-b721-a89ba5f40c4b

Encompassing global cooling, the spread of grasslands, and biogeographic interchanges, the Hemphillian North American Land Mammal Age is an important interval for understanding the factors driving ecological and evolutionary change through time. McKay Reservoir near Pendleton, Oregon is a natural laboratory for analyses of these factors. It is remarkable for its small vertebrate fauna including rodents, bats, turtles, and lagomorphs, but also for its larger mammal fossils like camelids, rhinocerotids, canids, and felids. Despite the importance of the site, few revisions to its faunal list have been published since its original description. We expand on this description by identifying taxa not previously known from McKay Reservoir based on specimens collected during fieldwork and through reidentification of previously collected fossils. Newly identified taxa include the borophagine canid Borophagus secundus (Matthew and Cook, 1909), the camelids Megatylopus Matthew and Cook, 1909 and Pleiolama Webb and Meachen, 2004, a dromomerycid, and the equids Cormohipparion Skinner and MacFadden, 1977 and Pseudhipparion Ameghino, 1904. Specimens previously assigned to Neohipparion Gidley, 1903 and Hipparion de Christol, 1832 lack the features necessary to diagnose these genera, which are therefore removed from the site's faunal list. The presence of Borophagus secundus, Cormohipparion, and Pseudhipparion is especially important, because each occurrence represents a major geographic range extension. This refined understanding of the fauna lays the foundation for future studies of taphonomy, taxonomy, functional morphology, and paleoecology—potentially at the population, community, or ecosystem levels—at this paleobiologically significant Miocene locality.

Central Europe is an area of high diversity for the Talpidae (Eulipotyphla, Mammalia) during the Late Miocene. The assemblages from Slovakia (Borský Svätý Jur, Krásno, Pezinok, Šalgovce, Studienka, Triblavina) are no exception with their abundant material representing eleven species. The uropsiline Desmanella is represented by D. rietscheli and D. dubia. Desmanini fossils are attributed to Archaeodesmana vinea, Archaeodesmana dissona new species, Gerhardstorchia biradicata, and Gerhardstorchia sp. The scalopines Proscapanus minor and P. austriacus are well recorded in the Vallesian localities and support the emergence of P. austriacus before the MN9/10 transition. Talpini and Urotrichini are especially rare and only represented by Talpa cf. T. minuta and Urotrichini gen. sp. indet. Finally, we identified the youngest occurrence of Desmanodon in Europe, D. cf. D. fluegeli, at the MN9 locality of Borský Svätý Jur. The high diversity in the Late Miocene Central European is partly explained by the co-occurrence of the competing Scalopini and Talpini during the Vallesian, indicating high resource environments. The decline of these tribes, followed by the success of the desmans during the Turolian, appears as a consequence of regional environmental changes.

UUID: http://zoobank.org/a3eb532b-c341-489a-b0ff-ecf3f9466a76

Walcottaspis vanhornei (Walcott, 1914) is a large, late Cambrian trilobite with a unique pygidial morphology known only from a narrow outcrop belt of the St. Lawrence Formation in the Upper Mississippi Valley. Found in carbonate-rich layers within heterolithic facies that represent the toesets of a prograding shoreface, it is restricted to a single or small number of parasequences. Only four specimens of any of its sclerites have been illustrated previously. Here holaspid examples of all its biomineralized sclerites are described and illustrated, along with a morphometric analysis of cranidial landmarks and landmarks plus semilandmarks for the pygidium. Ontogenetic allometry accounts for 29% of the variance among holaspid cranidia and includes a relative shortening and narrowing of the palpebral lobe and a reduction in the relative length and width of the frontal area. Notable pygidial phenotypic variation occurs in the extent of the postaxial region and in the proportion of the structure occupied by the axis. Phylogenetic analysis suggests that W. vanhornei is sister taxon to Dikelocephalus minnesotensis Owen, 1852, which also occurs in the St. Lawrence Formation and has a broadly similar cephalon but distinctive trunk. The holaspid pygidium of W. vanhornei is uniquely characterized by the interpleural furrows of the first two segments becoming abruptly obsolete on approaching the axial furrow. Some pygidia show narrow, shallow, flat-bottomed grooves etched into the internal sides of the dorsal surface or doublure that apparently represent infestation of the live trilobite.

The Weng'an Biota from the Ediacaran Doushantuo Formation in Guizhou Province, southwestern China, is known for its three-dimensionally phosphatized acritarchs, multicellular algae, and embryo-like animal fossils. Among these diverse microfossils, acanthomorphic acritarchs have played a significant role in the biostratigraphic subdivision and correlation of the lower-middle Ediacaran System. However, most previous studies on the biostratigraphy of the Doushantuo Formation in the Weng'an area have focused on large acanthomorphic acritarchs (LAAs, vesicle diameter >200 μm), whereas the smaller acanthomorphic acritarchs (SAAs, vesicle diameter <100 μm) from the Weng'an Biota have been largely overlooked. In this study, we examined >500 thin sections and discovered a large number of well-preserved, small (<100 μm) and medium-sized acanthomorphic acritarchs (MAAs, vesicle diameter ranging 100–200 μm). In total, we have identified SAAs in four genera and six species (Tanarium conoideum Kolosova, 1991, emend. Moczydłowska et al., 1993; Tanarium elegans Liu et al., 2014; Mengeosphaera membranifera Shang, Liu, and Moczydłowska, 2019; Mengeosphaera minima Liu et al., 2014; Estrella recta Liu and Moczydłowska, 2019; Variomargosphaeridium gracile Xiao et al., 2014), as well as two types of MAAs (Tanarium tuberosum Moczydłowska, Vidal, and Rudavskaya, 1993, emend. Moczydłowska, 2015; Weissiella cf. W. grandistella Vorob'eva, Sergeev, and Knoll, 2009, emend. Liu and Moczydłowska, 2019). This updated acritarch assemblage of the Weng'an Biota is valuable for correlating the Ediacaran Doushantuo Formation between the Weng'an and Yangtze Gorges areas. It also serves as a tool to test the proposed acritarch biozones in Ediacaran formations of South China and other localities, including Australia, Siberia, and the East European Platform.

The fossil genus Heterocladus LoDuca, Kluessendorf, and Mikulic, 2003 was established based on specimens from the Silurian (Llandovery) of southeastern Wisconsin, USA (LoDuca et al., 2003). This genus is monotypic and contains only the type species Heterocladus waukeshaensis LoDuca, Kluessendorf, and Mikulic, 2003, regarded as a noncalcified dasycladalean alga (LoDuca et al., 2003). Heterocladus waukeshaensis shows a narrow, undivided main axis and two types of laterals. Hair-like, branched laterals are arranged in whorls at lower part of the main axis, whereas clavate, undivided laterals appear at the upper part (LoDuca et al., 2003). The generic name is derived from the Greek hetero and klados, meaning ‘different’ and ‘branches,’ respectively (LoDuca et al., 2003).

Here we describe the first articulated olenid trilobite specimens recovered from the lowermost Fezouata Shale Formation (lower Tremadocian, Ordovician) of Morocco. Prior to the discovery of this sample, only two partial olenid trilobite specimens had been found from this part of the rock record. The specimens are well preserved enough to confidently identify as Leptoplastides salteri (Callaway, 1877), extending the species geographic range from Avalonia into Gondwana. We argue that the Moroccan occurrences formerly referred to as “Beltella sp.” in the literature are likely to be those of L. salteri. This species is the only olenid trilobite known from African Gondwana.

Paraconularia planicostata (Dawson, 1868) is one of two species in this genus (Sinclair, 1940) of conulariid cnidarian currently known from Mississippian strata in the Maritimes Basin in Atlantic Canada (Babcock and Feldmann, 1986). A salient characteristic of the species is the presence of a low and narrow internal carina at or near the longitudinal midline of each of the four faces of the gently tapered periderm (Van Iten et al., 2020). Paraconularia planicostata occurs in marine carbonates in the Upper Mississippian lower Windsor and lower Codroy groups in Nova Scotia and western Newfoundland, respectively (e.g., Bell, 1929; Stacy, 1953; Dix and James, 1988; Boehner et al., 1989; Boehner and Prime, 1993; Lavoie and Sami, 1998; Jutras et al., 2006; Ryan and Giles, 2017; Van Iten et al., 2020). The species is exceptionally abundant, with richly fossiliferous biohermal limestones containing up to approximately 20 specimens per 1000 cm3 of host rock (Van Iten, unpublished observations)—a volumetric density matched by few other conulariid-bearing rock units.

We published a series of papers regarding the oldest turritellids, naticids, their paleoecological interaction, and gastropod biozonation, which are of Oxfordian in age, from the Jhura pond section, Kutch, western India. Recently, an Oxfordian age was challenged by Fürsich et al. (2023) and they argued for a Cenozoic age. The authors reproduced a local geological map based on regional data where the Jhura pond section sediments were overlying the Bhuj Formation. In the original regional data, there was no Bhuj Formation and the introduction of the Bhuj Formation served to show that Jhura pond section sediments were “allochthonous”. Other lines of argument against our conclusions (e.g., identification of associated bivalve fauna, foraminiferal assemblage, and geological context) were brought forward. There were additional inconsistencies, such as the reworking of Oxfordian fossils, in their comment/opinion pieces. The only hard evidence was the report of a microfaunal assemblage, but the taxa were identified at the generic level and most of the genera appear in the Jurassic or even earlier.

Here we provide detailed and concrete evidence explaining features at the Jhura pond section, such as the subvertical nature of the beds, the ooid-bearing lithologies, the presence of various Oxfordian fossils, the difference in turritellids, naticid assemblages, and differences in the diversity curves between the present beds and the lower Miocene Chhasra Formation of Kutch. Detailed paleoecological analyses (both gastropods and bivalves) speak for two paleocommunities. We, therefore, reiterate that the present Jhura pond section sediments are Oxfordian in age and validate all the interpretations and conclusions that we have made in our previous papers.