Late Triassic coniferous species of silicified woods are described from the Tronquimalal Group, Llantenes Depocenter of the Neuquén Basin, southern Mendoza Province, Argentina. The new species Agathoxylon cozzoi and Agathoxylon lamaibandianus Crisafulli and Herbst, 2011 described in this study were found in proximal volcaniclastic facies deposited in alluvial fans and proximal braided river plains of the Chihuido Formation, which is the basal unit of the Group. The species A. lamaibandianus Crisafulli and Herbst, Protojuniperoxylon ischigualastense (Bonetti, 1966) Bodnar and Artabe, 2007, and the new species Cupressinoxylon llantenesense also described in this study were collected from the upper fluvio-deltaic plain and delta-plain deposits that prograded into a large, meromictic and wedge-shaped lake of the overlying Llantenes Formation. The Tronquimalal Group yields abundant and well-known Triassic plant remains of the Southern Gondwana “Dicroidium Flora,” although it also contains typical early Jurassic taxa displaying age affinities with other Argentinean “Florian Stage” communities of Late Triassic (Norian–?Rhaetian). The lignotaxa described from both units of the Tronquimalal Group may all together represent coniferous forests of the extratropical area of the Southwestern Province of Gondwana. Deciduous conifer forests associated with herbaceous and shrub communities dominated by ferns and smaller corystosperms, and other taxa including the Linguifolium leaves within the Llantenes Depocenter environments, were developed on the western margin of the continent under seasonal temperate-warm and humid to sub-humid climate with a marine influence from the west.

The Lakeview Limestone is one of the westernmost Cambrian exposures in the northwestern United States and occurs on the western edge of the Montania paleotopographic high. These deposits occur between the deeper water deposits to the west and carbonate banks and intracratonic basins to the east and provide critical link between the regions. A re-investigation of the Cambrian trilobite faunas from the lower portion of the Lakeview Limestone, Pend Oreille Lake, Idaho, is undertaken due to the inadequate illustrations and descriptions provided by Resser (1938a). Resser's type specimens and additional material are figured and described. The trilobite assemblages represent the Ptychagnostus praecurrens Zone, Wuliuan Stage, Miaolingian Series and including two new taxa: Itagnostus idahoensis n. sp., and Utia debra n. sp. Because of the similarity between some species of Amecephalus from the Lakeview Limestone to specimens from the Chisholm Shale, Nevada, the type specimens of Amecephalus piochensis (Walcott, 1886) and Am. packi (Resser, 1935), Walcott's and Resser's type specimens are re-illustrate and their taxonomic problems are discussed. Utia curio Walcott, 1924 from the Spence Shale, Utah, have never been re-illustrated since Walcott (1925), these type specimens are also re-illustrated and compared to Utia debra n. sp.

UUID: http://zoobank.org/5ef6ee5e-bddc-4395-becf-9bcea54c679c

The earliest known interpreted spatial competition between two species of stromatoporoids, Clathrodictyon cf. C. mammillatum (Schmidt, 1858) and Labechia sp. is found in the Upper Ordovician Xiazhen Formation at Zhuzhai, South China. The interaction between these taxa was initiated by settlement of Labechia sp. on the surface of Clathrodictyon cf. C. mammillatum. Distortions of the intraskeletal elements of stromatoporoids represented by abnormally large, wide cysts and thick cyst plates in Labechia sp. are observed, along with zigzag crumpled distorted laminae and antagonistic behavior of the skeleton in Clathrodictyon cf. C. mammillatum, indicating syn-vivo interactions. The growth of Labechia sp. was terminated by the overgrowth of Clathrodictyon cf. C. mammillatum, possibly reflecting the ecological superiority of Clathrodictyon cf. C. mammillatum over Labechia sp. The observations are interpreted as competitive interaction between stromatoporoids that was most likely facultative, thus most likely occurring by chance, but the interaction allows assessment of different growth behaviors of the stromatoporoid species. Analysis of the interaction provides evidence to improve understanding of the paleoecology and growth behaviors of early stromatoporoids.

Twenty-six genera and 34 species of early Miocene Indian shallow-marine ostracodes were examined for taxonomy and paleobiogeography. A new genus Paractinocythereis and new species Costa ponticulocarinata were described. Early Miocene Indian ostracode fauna shows strong affinity to Eocene–Miocene Eastern and Western Tethyan ostracode faunas and Miocene–Recent Indo-Pacific ostracode fauna, supporting the Hopping Hotspot Hypothesis that the Tethyan biodiversity hotspot has shifted eastward through Arabia to Indo-Australian Archipelago (IAA) together with concomitant biogeographic shifts of the Tethyan elements. The result also indicated an inverse westward distributional shift in a genus. It is important to note that Paleogene and Miocene shallow marine ostracodes from the IAA region remain poorly investigated, and more fossil ostracode data are needed to better test the Hopping Hotspot Hypothesis.

UUID: http://zoobank.org/d1e29249-8c5b-49bf-a47a-5f18e1fc4426

Dilophosaurus wetherilli was the largest animal known to have lived on land in North America during the Early Jurassic. Despite its charismatic presence in pop culture and dinosaurian phylogenetic analyses, major aspects of the skeletal anatomy, taxonomy, ontogeny, and evolutionary relationships of this dinosaur remain unknown. Skeletons of this species were collected from the middle and lower part of the Kayenta Formation in the Navajo Nation in northern Arizona. Redescription of the holotype, referred, and previously undescribed specimens of Dilophosaurus wetherilli supports the existence of a single species of crested, large-bodied theropod in the Kayenta Formation. The parasagittal nasolacrimal crests are uniquely constructed by a small ridge on the nasal process of the premaxilla, dorsoventrally expanded nasal, and tall lacrimal that includes a posterior process behind the eye. The cervical vertebrae exhibit serial variation within the posterior centrodiapophyseal lamina, which bifurcates and reunites down the neck. Iterative specimen-based phylogenetic analyses result in each of the additional specimens recovered as the sister taxon to the holotype. When all five specimens are included in an analysis, they form a monophyletic clade that supports the monotypy of the genus. Dilophosaurus wetherilli is not recovered as a ceratosaur or coelophysoid, but is instead a non-averostran neotheropod in a grade with other stem-averostrans such as Cryolophosaurus ellioti and Zupaysaurus rougieri. We did not recover a monophyletic ‘Dilophosauridae.’ Instead of being apomorphic for a small clade of early theropods, it is more likely that elaboration of the nasals and lacrimals of stem-averostrans is plesiomorphically present in early ceratosaurs and tetanurans that share those features. Many characters of the axial skeleton of Dilophosaurus wetherilli are derived compared to Late Triassic theropods and may be associated with macropredation and an increase in body size in Theropoda across the Triassic-Jurassic boundary.

This paper presents new descriptions of Anacardiaceae fossil woods from the Ituzaingó Formation (late Cenozoic) at the Toma Vieja, Curtiembre, and Arroyo El Espinillo localities, Argentina. We describe eight silicified woods assigned to four different species in three genera, one of which, Parametopioxylon crystalliferum n. gen. n. sp., is new. Similarities between these three genera and the six Anacardiaceae species previously recorded from the late Cenozoic in northeastern Argentina are investigated using multivariate analysis techniques (correspondence and cluster analysis). Our study is based on 33 characters scored for 17 fossil specimens (10 Astroniumxylon Brea, Aceñolaza, and Zucol 2001; five Schinopsixylon Lutz, 1979; and two Parametopioxylon n. gen.) and four extant species (Astronium balansae Engl., Astronium urundeuva Engl., Schinopsis balansae Engl., and Metopium sp.). Our main goal is to determine the wood anatomical features useful for distinguishing among these species. Results of the multivariate analyses support the previous classification where Schinopsixylon is distinguished from Astroniumxylon by having exclusively paratracheal axial parenchyma, ≥30% multiseriate rays, and multiseriate rays that are ≥5 cells wide and commonly 301–400 μm in height. Additionally, we propose that Schinopsixylon heckii Lutz, 1979 is synonymous with S. herbstii Lutz, 1979. A diagnostic key for the fossil species studied is given. Wood anatomy of Anacardiaceae fossil woods from Argentina (late Cenozoic) suggests a warm, dry to semi-humid climate for this region, supporting previous studies.

Several specimens of Dickinsonia cf. D. menneri, originating from a single burial event at the Lyamtsa locality of the late Ediacaran (Vendian) in the southeastern White Sea area, Russia, represent deviations from normal morphology: a reduction in the total length of the body; the loss of portions of the body; various deformations of the transverse elements, called isomers; and splitting of the longitudinal axis with the formation of two posterior ends. It is assumed that these deformations were formed as a result of non-lethal damage, which occurred long before the burial event, and the response of Dickinsonia to them. The progress of the regeneration process at the damaged areas, and especially its deviations, indicates that the growth zone was located at the posterior end of the Dickinsonia body. The cause of non-lethal damage to Dickinsonia could not be established, but the local distribution of deformed specimens preserved in the same burial event alongside cyanobacterial colonies, and the presence of weak deformations, expressed only in shortening of the length of some isomers, lead to the conclusion that damage resulted from short episodes of physicochemical impact, rather than occasional attacks by a hypothetical macrophage.

The Oligocene strata of the Qom Formation from the Tajar-Kuh section, Central Iran, are rich in various Larger Benthic Foraminifera (LBF). Morphometric studies of the internal features of the LBF tests were carried out based on matrix-free specimens from seven samples. The LBF assemblage studied in 24 populations mainly contains representatives of two nummulitid (the reticulate Nummulites bormidiensis Tellini, 1888, only in the lower three samples, and the radiate Nummulites kecskemetii Less, 1991 in all samples) and of two lepidocyclinid lineages. Of the latter, Nephrolepidina praemarginata (R. Douvillé, 1908) occurs in all the samples, whereas Eulepidina formosoides H. Douvillé, 1925 is present in the lower six samples. In the upper sample, the slightly more advanced Eulepidina ex. interc. formosoides H. Douvillé, 1925 et dilatata (Michelotti, 1861) is recorded. Due to the very similar taxonomic composition of the Tajar-Kuh section with their coeval faunas of the Mediterranean, the age was evaluated in the frame of the Western Tethyan Oligo-Miocene shallow benthic zonation (SBZ). Although the presence of E. formosoides suggests late Rupelian (SBZ 22A Zone) age, the occurrence of Heterostegina assilinoides, N. kecskemetii, N. bormidiensis, and Planolinderina sp. preferably represents the SBZ 22B Zone of the early Chattian. Based on the obtained results, at least the lower six samples can indicate the very basal part of the Chattian. More advanced Eulepidina from the uppermost sample suggests a slightly younger but still early Chattian age.

Systematic analysis shows that the Southern Hemisphere bivalve genus Retrotapes includes the Antarctic species R. antarcticus, R. newtoni, and R. robustus and recognizes for the first time the presence of Katelysia represented by K. florentinoi. Two new genera were erected in this study: Marciachlys new genus to include M. inflata new combination, and Adelfia new genus, which includes A. austrolissa new combination and A. omega new species from the Eocene of Antarctica, and the late Eocene Chilean A. arenosa new combination. Eurhomalea carlosi was synonymized with K. florentinoi; Cyclorismina marwicki with R. antarcticus; Gomphina iheringi was considered an indeterminate species; and Cockburnia lunulifera was excluded from the Tapetinae. These systematic assignments are supported by a phylogenetic analysis, which recognizes an Austral clade of Tapetinae, comprising all the genera mentioned above, along with Marcia, Paleomarcia, Atamarcia, and Protapes.

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Three species of Habrostroma dominate stromatoporoid faunas in the Lower Devonian (Lochkovian) of five areas in North America: New York, Virginia, Maine, Bathurst Island, and Ellesmere Island. In addition, they occur in what could be the upper Silurian (uppermost Pridoli) of Virginia, and possibly New York. Measurements of nine morphologies from 127 specimens of Habrostroma were subjected to an average linkage cluster analysis. Using average linkage between groups, three distinct clusters were revealed. Group assignments made from the cluster analysis were saved, and entered into a canonical discriminant analysis with the nine morphological variables. An overall Wilks’ lambda was calculated, and is statistically significant at alpha <0.001. The hit rate for classifying group 1 is 98%, that for group 2 is 100%, and that for group 3 is 97.9%; the total hit rate is 100%. The morphological variables contributing most to group membership are: (1) percent cystlike microlaminae, (2) microlaminae per mm, (3) gallery height, (4) laminae per mm, and (5) laminar thickness. The statistics confirm that there are three species: H. centrotum, H. microporum, and H. consimile.

Habrostroma centrotum occurs in all five areas. This is unusual because Virginia, New York, and Maine are part of the Eastern Americas Realm, and the arctic islands are part of the Old World Realm. Separation of the realms is based on a high percentage of unique genera in each. A breach in the inter-realm barrier is proposed to have existed across the Canadian Shield during the Lochkovian. The nature of the breach is determined to be a shallow-water filter, allowing the passage of a limited number of taxa.

During recent stratigraphical and micropaleontological investigations of the Gulupu section in Tüna, Yadong, of the Eocene Zhepure Formation, numerous holoplanktonic mollusks (pteropods) were recovered. Four species, assignable to two genera of pteropods (including Limacina yadongensis new species) were systematically described and illustrated, and a gastropod-bivalve biofacies was identified. This is the first report of Eocene (Ypresian) pteropods in southern Tibet; the same stratum also yields many other neritic faunas. The data presented in this study suggest that a semi-closed restricted gulf in the Tüna area existed and the occurrence of pteropods in Tüna may indicate transport from more open, deep water by oceanic currents during early Eocene. Based on the analysis of paleogeographical distribution of pteropods, it indicates that a Tethys seaway existed during the early Eocene (Ypresian).

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A new, previously undescribed Middle Ordovician (middle Darriwilian: Dw2) radiolarian assemblage has been recovered from the Table Cove Formation at Piccadilly Quarry, western Newfoundland. Constituents of the fauna described herein are both distinctive and exceptionally well preserved. Three-dimensional X-ray micro-computed tomography (μ-CT) is used to make a detailed examination of four key spumellarian specimens. This technology enables visualization of hitherto ambiguous details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has impeded resolution of higher taxonomic rankings.

Among Permian smaller foraminifers, the genus Dagmarita is one of the most studied due to its worldwide distribution. The detailed study of the Zal (NW Iran) and Abadeh (Central Iran) stratigraphic sections led to redescription of the genus Dagmarita and its taxonomic composition. In Dagmarita, a peculiar generic morphological character, represented by a secondary valvular projection, has been detected for the first time among globivalvulinid foraminifers. The phylogeny of Dagmarita, and in particular its ancestor Sengoerina, is discussed and the new species, D. ghorbanii n. sp. and D. zalensis n. sp., are introduced. Analogies and differences among all the species belonging to Dagmarita are highlighted and morphological features of the new taxa are shown in 3D reconstructions, useful for understanding differently oriented sections of the specimens in thin section.

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Bituminous limestone of the Ediacaran Shibantan Member of the Dengying Formation (551–539 Ma) in the Yangtze Gorges area contains a rare carbonate-hosted Ediacara-type macrofossil assemblage. This assemblage is dominated by the tubular fossil Wutubus Chen et al., 2014 and discoidal fossils, e.g., Hiemalora Fedonkin, 1982 and Aspidella Billings, 1872, but frondose organisms such as Charnia Ford, 1958, Rangea Gürich, 1929, and Arborea Glaessner and Wade, 1966 are also present. Herein, we report four species of Arborea from the Shibantan assemblage, including the type species Arborea arborea (Glaessner in Glaessner and Daily, 1959) Glaessner and Wade, 1966, Arborea denticulata new species, and two unnamed species, Arborea sp. A and Arborea sp. B. Arborea arborea is the most abundant frond in the Shibantan assemblage. Arborea denticulata n. sp. resembles Arborea arborea in general morphology but differs in its fewer primary branches and lower length/width ratio of primary branches. Arborea sp. A and Arborea sp. B are fronds with a Hiemalora-type basal attachment. Sealing by microbial mats and authigenic cementation may have played an important role in the preservation of Arborea in the Shibantan assemblage. The Shibantan material of Arborea extends the stratigraphic, ecological, and taphonomic ranges of this genus.

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The recent description of the nevadioid trilobite Buenellus chilhoweensis Webster and Hageman, 2018 established the presence of early Cambrian Montezuman Stage (Cambrian Series 2, Stage 3) faunas in the Murray Shale of Chilhowee Mountain, Tennessee. The description recognized the oldest known age-diagnostic Cambrian trilobite from the Laurentian margin of the former Iapetus Ocean since Buenellus Blaker, 1988 is known otherwise only from the Sirius Passet Lagerstätte on the Innuitian margin of North Greenland. The bivalved arthropods Isoxys chilhoweanus Walcott, 1890 and Indota tennesseensis (Resser, 1938a) have also been described from the Murray Shale, but hyolithids appear to be the dominant body fossils in terms of diversity and abundance. Although poorly preserved, the hyolithids occurring together with Buenellus chilhoweensis are described to improve understanding of the Murray Shale biota. The hyolith assemblages of the Murray Shale and Sirius Passet Lagerstätte are not closely similar, although the poor preservation of both hinders comparison.

Non-spicular sponges constitute >8% of the extant sponge biodiversity at the species level, yet their evolutionary history is poorly known due to a sparse fossil record. The genus Vauxia, previously only known from middle Cambrian (Miaolingian, Wuliuan) Lagerstätten, was regarded as the earliest fossil record of non-spicular demosponges. Here we describe the first vauxiid sponge, Vauxia leioia new species, from the early Cambrian Chengjiang Biota (Series 2, Stage 3). This sponge exhibits a double-layered fibrous skeleton: the mesh and fiber thickness of the endosomal layer are irregular while the dermal layer, which directly connects with the endosomal skeleton without intermediate supporting fibers, is regular in both aspects. Measurements using scanning electron microscope and Raman spectroscopy revealed that the endosomal fibers are composed of carbonaceous material, but are tomographically indiscernible from the host rock, while the dermal fibers are preserved as impressions without obvious accumulation of carbonaceous material. Although the original composition of the dermal skeleton is now hard to establish, we cannot rule out that it was siliceous. The morphological characters of V. leioia n. sp. represent an intermediate state between other Vauxia species and the recently established vauxiid genus Angulosuspongia. However, more data are required to reconstruct the phylogenetic relationship among these taxa.

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