A new Early Cretaceous neosuchian crocodyliform is recognized on the basis of two skulls and postcranial material collected from the late Aptian Twin Mountains Formation at Proctor Lake, central Texas. The new species, Wannchampsus kirpachi, is distinguished by a unique combination of characters including an enlarged third maxillary tooth, internal choanae bordered anteriorly by the palatines and by the pterygoids posteriorly and laterally, anterior margin of the choanae situated at the posterior edge of the suborbital fenestrae, a median crest along the midline of the parietal and frontal, and procoelous vertebrae. A phylogenetic analysis recovered the new taxon as the sister to the ‘Glen Rose form,’ an undescribed taxon of neosuchian. Together, with Shamosuchus, Batrachomimus, and Rugosuchus, they form a monophyletic group, Paralligatoridae, that is the sister clade to Eusuchia within Neosuchia. The Proctor Lake taxon and the undescribed yet widely discussed ‘Glen Rose form’ are referable to the same genus.

The new genus Tanycythere (Crustacea, Ostracoda) is described from the Jurassic (Hettangian–Bathonian) of western and central Europe based on T. caudata new species, T. praecaudata praecaudata new subspecies, T. praecaudata parallela new subspecies, T. duartei new species, T. posteroelongata new species, and T. wattonensis new species. Another new species, T. procera, is described from the Lower Cretaceous (?Barremian). Recognition of a new genus comprising six new species and subspecies indicates that overall Jurassic and Early Cretaceous ostracod biodiversity is underestimated.

In order to clarify the pattern of diversification and processes of biological activity during the Cambrian radiation, ichnofossils were comparatively studied in the early Cambrian sections of Newfoundland, South China and western Mongolia. Special attention was paid to size distributions of the most common ichnogenus, Planolites, and the densities of all the observed ichnofossils that preserve animal activity as expressed by bedding plane bioturbation indices (BPBI).

From the Fortune Head section in Newfoundland, a clear size increase in the ichnogenus Planolites is confirmed from the Treptichnus pedum Zone to the overlying Rusophycus avalonensis Zone. The BPBI also shows much stronger biological activity in the R. avalonensis Zone than in the T. pedum Zone. In Meishucun, South China and Gobi-Altai, Mongolia, however, a variety of Planolites sizes had already appeared in the T. pedum Zone, and the BPBI's on some bedding surfaces of the T. pedum Zone are already comparable to those in the R. avalonensis Zone in Newfoundland. In the earliest Cambrian, diversification and increase in the biological activity of the benthic fauna were diachronous in the wide geographic scale, starting earlier at lower latitudes (South China and western Mongolia) than at higher latitudes (Newfoundland), reflecting differences in the onset of Cambrian benthic animal activity under different climatic conditions.

Taxonomic descriptions of diploporites from the middle Silurian of eastern Laurentia have focused nearly entirely on thecal plating, with minimal description or figuring of attachment structures. A recently discovered hardground surface within the Wenlock-age (Sheinwoodian) Massie Formation that is encrusted by numerous well-preserved pelmatozoan holdfasts, including structures identifiable as diploporite thecal attachments, provides an opportunity to document the morphology of these rarely described structures. Moderately thin-walled structures with a parabolic, depressed central area composed of seven distinct marginal plates with prominent pores appear to represent thecal attachments of the broad-based trematocystinid holocystitid Paulicystis. Thick-walled, steep-sided structures composed of five to seven fused or partially fused plates with less prominent pores, a deep stelar depression, and radiating canals appear to represent thecal attachments of undetermined, possibly holocystinid or pentacystinid holocystitids. All diploporite holdfasts are cemented to fine-grained, well-sorted skeletal substrates on elevated crests of the hardground surface, but are not found on microbioherms.

Paleontologists have long speculated that the bizarre, giant Ordovician gastropods Maclurites Le Sueur, 1818 and Maclurina Ulrich and Scofield, 1897 lived more like suspension-feeding oysters than typical algivorous snails. Geometric and eigenshape morphometrics demonstrate the plausibility of this lifestyle, but with a twist. The apertures of these gastropods were small ellipsoids when young, transitioning rapidly to polygonal morphologies at maturity, with angulations (sinuses) occurring in regions associated with development of mature ctenidia (gills) and enhanced stability on the seafloor. Combined with knowledge of extant suspension-feeding gastropods and functional and phylogenetic analysis of the anatomy of other fossil relatives, this ontogenetic pattern suggests these snails began life as typical mobile algae-grazers, but switched to sedentary suspension-feeders as they aged.

Arctotherium angustidens Gervais and Ameghino, 1880 (the South American giant short-faced bear) is known for being the earliest (Ensenadan Age, early to middle Pleistocene) and largest (body mass over 1 ton) of five described Arctotherium species endemic to South America. Here we assess the diet of this bear from multiple proxies: morphology, biomechanics, dental pathology, stable isotopes and a previous study using geometric morphometric methodology. Results favor the idea of animal matter consumption, probably from large vertebrates in addition to vegetable matter consumption. Most probably, active hunting was not the unique strategy of this bear for feeding, since its large size and great power may have allowed him to fight for the prey hunted by other Pleistocene carnivores. However, scavenging over mega mammal carcasses was probably another frequent way of feeding. South American short-faced bears adjusted their size and modified their diet through Pleistocene times, probably as a response to the diversification of the carnivore guild (from the few precursory taxa that crossed the Panamanian Isthmus during the Great American Biotic Interchange).

Although there is a generally accepted framework for the Permian marine biogeography of Australia, significant uncertainties remain concerning the temporal biogeographical changes closely related to the timing of Permian glacial–interglacial events. Several recent studies along these research lines demonstrate the importance of a reliable high-resolution biostratigraphical timescale for paleobiogeographical and paleoclimatic reconstructions. This paper provides, for the first time, a full taxonomic and biostratigraphical study of the brachiopod fauna from the Wasp Head Formation, southern Sydney Basin, southeastern Australia. The fauna is associated with deposits of the first Permian glacial interval suggested for eastern Australia. Three brachiopod assemblages are recognized. The lower and middle assemblages contain scarce brachiopods although associated bivalves are comparatively more common. Despite very low diversity and low abundance, these two brachiopod assemblages contain characteristic species of the Strophalosia concentrica and Strophalosia subcircularis brachiopod zones, both considered of late Asselian age. The third assemblage, occurring in the uppermost part of the formation, contains more brachiopods than bivalves and is referred to early Sakmarian in age. The species diversity and stratigraphic occurrences of the brachiopod assemblages in relation to sedimentary facies suggest that the lower two assemblages may represent an intra-glacial interval while the younger third assemblage, characterized by abundant occurrences of Trigonotreta and Tomiopsis species, accompanied by the bivalve Eurydesma, is more indicative of a post-glacial benthic marine fauna comparable to coeval brachiopod faunas found elsewhere in Gondwana.

This paper serves two roles. First, it acts as an introduction to Blender, an open-source computer graphics program, which can be of utility to paleontologists. To lessen the software's otherwise steep learning curve, a step-by-step guide to create an idealized reconstruction of a fossil in the form of a three-dimensional model in Blender, or to use the software to render results from ‘virtual paleontology' techniques, is provided as an online supplemental data file. Second, here we demonstrate the use of Blender with a case study on the extinct trigonotarbid arachnids. We report the limb articulations of members of the Devonian genus Palaeocharinus on the basis of exceptionally preserved fossils from the Rhynie Cherts of Scotland. We use these newly reported articulations to create a Blender model, and draw comparisons with the gait of extant arachnids to produce as accurate a representation of the trigonotarbid flexing its limbs and walking as possible, presented in additional online supplemental data files. Knowledge of the limb articulations of trigonotarbid arachnids also allows us to discuss their functional morphology: trigonotarbids' limbs and gait were likely comparable to extant cursorial spiders, but lacked some innovations seen in more derived arachnids.

The Pratt Ferry beds are a three meter thick bioclastic carbonate unit containing the Pygodus serrus–P. anserinus conodont zone boundary and lying just below the Nemagraptus gracilis graptolite zone at a single locality in Alabama. Telephina Marek at Pratt Ferry and other eastern North American localities is represented by at least six species. These are judged widespread and in part conspecific with Scandinavian or Asian forms of similar age. Most of the fifteen Appalachian telephinid species proposed by Ulrich (1930) are reviewed and some synonymized. Bevanopsis Cooper is present, extending its stratigraphic range via B. buttsi (Cooper). The original description of Ceraurinella buttsi Cooper is augmented. Other recorded but poorly represented genera include Ampyxina, Arthrorhachis, Calyptaulax, Hibbertia, Lonchodomas, Mesotaphraspis, Porterfieldia, and Sphaerexochus. The entire faunule represents a mixture of ‘inshore’ and ‘offshore’ or planktonic faunal elements rarely seen elsewhere in the latest Middle Ordovician (Darriwilian) of eastern North America.

The analysis of trace fossils usually is performed qualitatively, which makes comparing trace fossils from different units less objective than quantitative approaches. Quantifying the shape of trace fossils enables scientists to compare trace fossils described by different people with greater precision and accuracy. This paper describes several methods for quantifying invertebrate trace fossils, including morphology dependent methods (motility index, mesh size, topology, tortuosity, branching angle, and the number of cell sides) and morphology independent methods (fractal analysis, burrow area shape, and occupied space percentage (OSP)). These tools were performed on a select group of graphoglyptid trace fossils, highlighting the benefits and flaws of each analytical approach. Combined together, these methods allow for more objective comparisons between different trace fossils.

Plesiosaurs and mosasaurs are identified from the Puskwaskau Formation of west-central Alberta, Canada. These deposits record the final stages during which the Western Interior Seaway remained open to the Boreal Sea to the North and therefore are important for determining the ranges of high-latitude marine reptiles. Polycotylid and elasmosaurid plesiosaurs shared these waters with russellosaurine (including plioplatecarpine) mosasaurs suggesting a diverse ecology of large-bodied marine predators occupied these high-latitude waters in the early Campanian. This locality, situated at 65°N paleolatitude, helps link the poorly known faunas from northern Canada with the better-known faunas from central and southern North America. Rare articulated material from the Puskwaskau Formation urges further investigation of this poorly explored unit.

A single specimen of a shrimp-like crustacean, Devonostenopus pennsylvaniensis, new genus and species is described from the Huntley Mountain Formation, which is Devonian–Carboniferous (Mississippian) in age. The specimen was collected in north-central Pennsylvania. Devonostenopus pennsylvaniensis is attributed to Stenopodidae. Co-occurrence of the specimen with pinnules of Archaeopteris halliana Goeppert, 1852, suggests that it is Devonian in age. Occurrence of a stenopodidean in the Devonian of North America is significant, as only three definitive decapods have been previously described from the Paleozoic and only two have been described from the Devonian. The earliest stenopodideans described to date are Cretaceous (Cenomanian and Santonian) in age. As such, Devonostenopus pennsylvaniensis extends the geologic range of Stenopodidea from Cretaceous to Late Devonian. Occurrence of a stenopodidean in the Devonian of North America, as well as the occurrence of the only two other known Devonian decapods in North America, suggests that Laurentia might have been a major area of endemism for Devonian decapods.

Palaeoaplysina is an enigmatic platy macrofossil with a cellular skeleton and internal canal system common to upper Carboniferous–lower Permian reefs of the northern hemisphere. Its rapid flourishing from the Moscovian and subsequent extinction near the end of the Sakmarian, as well as its unique combination of physical features, are poorly understood. In addition to Palaeoaplysina reefs forming major petroleum exploration targets in Russia, Palaeoaplysina is abundant and well preserved in the Sverdrup Basin in the Canadian Arctic Archipelago. A new genus of Palaeoaplysinaceae, Eopalaeoaplysina n. gen., is also widespread in the Sverdrup Basin and identified based on a simple morphology with broad canals distributed in roughly even rows. The distribution of paleoaplysinids in strata from the Moscovian to the Sakmarian in the Sverdrup Basin reveals Eopalaeoaplysina and Palaeoaplysina represent two distinct reef-building forms with an increase in complexity over time. The aragonitic composition of Palaeoaplysina, in addition to its distribution within the photic zone and differentiated cellular skeleton, suggests paleoaplysinids were ancestral red algae. Palaeoaplysina occurs in both low-energy back-reef and higher-energy reef front facies. Preserved thin edges of Palaeoaplysina plates indicate it was encrusting, at least in low-energy conditions. The exclusion of Palaeoaplysina from the late Paleozoic tropics and the southern hemisphere, its rapid appearance and proliferation, and its eventual extinction may point towards an evolutionary niche optimized for warm-water conditions at unusually high latitudes along the western margin of Pangea.

Disc-like fossils from siltstones of the Taozichong Formation (Cambrian) in the Qingzhen area, Guizhou, South China are reported here. They are similar to some Ediacaran and Phanerozoic discoidal fossils, and assigned to Tirasiana? disciformis? Palij, 1976. Based on the study of 43 specimens, dewatering or fluid escape structures, soft-sediment loading, scratch circles or other inorganic origins are ruled out, and the fossil is interpreted as a discoidal body fossil of unknown affinities rather than trace fossils. Energy-dispersive X-ray spectroscopy and elemental mapping analyses reveal that the discoid fossils contain higher concentrations of C, Fe, and P than the surrounding matrix, indicating the possible presence of pyrite, apatite, and organic carbon as a result of authigenic mineralization in association with decay and early diagenetic processes. The possible presence of extracellular polymeric substance suggests that the discs were surrounded by thin microbial mats composed primarily of extracellular polymeric substances, which facilitated their fossilization by promoting conditions that are favorable to secondary mineral precipitation. The new specimens provide useful information about the phylogenetic affinities of these early discoidal fossils and help us to better understand the taphonomic modes of non-biomineralizing organisms in Ediacara-type and Burgess Shale-type biotas.

Phylogenetic analyses of the Cambrian spiny oryctocephalids support the elevation to familiar rank of Oryctocephalidae Beecher, 1897 and indicate that the family can be divided into two clades, here designated as the subfamilies Oryctocephalinae Beecher, 1897 and Lancastriinae Kobayashi, 1935. Curvoryctocephaliinae Zhao and Yuan in Yuan et al., 2002 is considered here a junior synonym of Lancastriinae. Oryctocephalinae have tapered or parallel sided glabella and is composed of species of Oryctocephalus Walcott, 1886. The subgenera Oryctocephalus (Oryctocephalus) and O. (Eoryctocephalus) Zhao and Yuan in Yuan et al., 2002 do not form separate clades and are here rejected.

The genera of the Lancastriinae have expanding glabellae. The subfamily is composed of a broad variety of genera that can be divided into three major subclades: Lancastria, Protoryctocephalus, and Oryctocephalites. The Lancastria subclade is composed of Lancastria Kobayashi, 1935, Changaspis Lee in Chien, 1961, and Goldfieldia Palmer, 1964 occurring at the base of the Lancastriinae. Goldfieldia and Lancastria form a sister group to Changaspis. The long branches in the phylograms indicated significant differences between these taxa; thus, the genus Goldfieldia is maintained. The Protoryctocephalus subclade is monogeneric and forms a sister group to the Oryctocephalites subclade. The Oryctocephalites subclade consists of several species of this genus and the more derived forms Metabalangia Qian and Yuan in Zhang et al., 1980 and Tonkinella Mansuy, 1916. Oryctocephaloides Yuan in Zhang et al., 1980 is considered a junior synonym of Oryctocephalites Resser, 1939. The subgenera Oryctocephalites (Oryctocephalites) and O. (Parachangaspis) Zhao and Yuan in Yuan et al., 2002 do not form separate clades. The later subgenus occurs in the basal portion of the Oryctocephalites subclade indicating that it is a paraphyletic taxon.

Opsiosoryctocephalus Sundberg, 1994, Oryctocephalops Lermontova, 1940, and Curvoryctocephalus Zhao and Yuan in Yuan et al., 2002 are not consistent in their placement within the phylogenetic analyses, although they always occur in the Lancastriinae. As a result they are not placed within a subclade within Lancastriinae.

The type species Goldfieldia pacifica Palmer, 1964 was based solely on cranidia. This species is redescribed using topotype material that includes cranidia, librigenae, hypostomes, thorax, and pygidia.

Phosphatized and phosphatic small shelly fossils are a major source of information concerning the evolution of animals during the early Cambrian. Although progress has been made in understanding some of these fossils, many remain enigmatic, both with regard to their phylogenetic affinities and the overall morphology of the animal from which isolated sclerites came. Two unusual fossils from the upper lower Cambrian (Qiongzhusian or Atdabanian) Xihaoping Member of the Dengying Formation from Xiaowan, Xixiang County, southeastern Shaanxi Province, China are described herein. The first of these is a cap-shaped fossil we describe as Cambroskiadeion xiaowanense new genus and species. On its concave surface it bears a spine, the base of which is covered with numerous hemispherical verruculae. The long spine indicates that this was a sclerite rather than a univalved shell, although it remains unclear from what sort of animal it came. Similar fossils have been hypothesized to be halkieriid valves; although the rarity of halkieriid sclerites in the present samples argues against this view, it is possible these fossils are part of a similar multi-element skeleton. The second fossil is Acidocharacus longiconus Qin and Ding, 1988; it is known only from the Xihaoping Member and consists of a tall spine, often bearing barbs or bumps, attached to a rounded conical base. The base is covered with verruculae similar to those found on Cambroskiadeion. The function of these elements, and whether they were internal or external, remains unknown.

The fossil record of solemydid turtles is primarily based on isolated fragments collected from Late Jurassic to Late Cretaceous sediments throughout North America and Europe and little is therefore known about the morphology and evolutionary history of the group. We here provide a detailed description of the only known near-complete solemydid skeleton, which was collected from the Lower Cretaceous (Aptian–Albian) Antlers Formation of Texas during the mid-twentieth century, but essentially remains undescribed to date. Though comparison is limited, the skeleton is referred to Naomichelys speciosa, which is based on an isolated entoplastron from the Lower Cretaceous (Aptian–Albian) Kootenai (Cloverly) Formation of Montana. The absence of temporal emarginations, contribution of the jugals to the orbits, and a clear subdivision of the middle and inner cavities, and the presence of elongate postorbitals, posteriorly expanded squamosals, a triangular fossa at the posterior margin of the squamosals, an additional pair of tubercula basioccipitale that is formed by the pterygoids, foramina pro ramo nervi vidiani (VII) that are visible in ventral view, shell sculpturing consisting of high tubercles, a large entoplastron with entoplastral scute, V-shaped anterior peripherals, and limb osteoderms with tubercular sculpture diagnose Naomichelys speciosa as a representative of Solemydidae. The full visibility of the parabasisphenoid complex in ventral view, the presence of an expanded symphyseal shelf, and the unusual ventromedial folding of the coronoid process are the primary characteristics that distinguish Naomichelys speciosa from the near-coeval European taxon Helochelydra nopcsai.

Bioerosion trace fossils in bones are defined as biogenic structures that cut or destroy hard bone tissue as the result of mechanical and/or chemical processes. Under the premise that their paleoecological potential can completely be realized only through correct taxonomic assignment, this work focuses on the methodology for naming these biogenic structures. Thus, we propose the following ichnotaxobases in order to assist in naming trace fossils in bones: general morphology, bioglyphs, filling, branching, pattern of occurrence, and site of emplacement. The most common general morphologies are: pits and holes (borings); chambers; trails; tubes; channels (canals); grooves; striae; and furrows. The main types of bioglyphs are grooves and scratches, which may display different arrangements, such as parallel and opposing, or arcuate paired. The nature of the fill may help recognition of the origin, composition, and relationship with the surrounding sediment, as well as processes of destruction or consumption of bony tissue. The structure and layout of the filling, such as meniscate backfill or pelleted filling, offer information about the bioeroding processes. Branching structures on cortical bone are present in canals and furrows. Where the trace penetrates spongy bone, branching structures are forming tunnels that may connect internal chambers. The common patterns of occurrence are individual, paired, grouped, overlapping, lined, and arcuate. The site of emplacement may be in cortical bone, spongy bone, articular surfaces, internal bone microstructures, and external bone anatomical structures. The use of substrate as an ichnotaxobase is problematic, but as biological substrate, bone itself is a valuable source of information for paleoecologic and ethologic inferences. Given the paleontological importance of bioerosion trace fossils in bones, we underscore interactions between ichnology and other sciences, such as forensic entomology, archaeology, paleoecology, and taphonomy.

Finite element analysis (FEA) is a powerful quantitative tool that models mechanical performance in virtual reconstructions of complex structures, such as animal skeletons. The unique potential of FEA to elucidate the function, performance, and ecological roles of extinct taxa is an alluring prospect to paleontologists, and the technique has gained significant attention over recent years. However, as with all modeling approaches, FE models are highly sensitive to the information that is used to construct them. Given the imperfect quality of the fossil record, paleontologists are unlikely to ever know precisely which numbers to feed into their models, and it is therefore imperative that we understand how variation in FEA inputs directly affects FEA results. This is achieved through sensitivity and validation studies, which assess how inputs influence outputs, and compare these outputs to experimental data obtained from extant species. Although these studies are restricted largely to primates at present, they highlight both the power and the limitations of FEA. Reassuringly, FE models seem capable of reliably reproducing patterns of stresses and strains even with limited input data, but the magnitudes of these outputs are often in error. Paleontologists are therefore cautioned not to over-interpret their results. Crucially, validations show that without knowledge of skeletal material properties, which are unknowable from fossilized tissues, absolute performance values such as breaking stresses cannot be accurately determined. The true power of paleontological FEA therefore lies in the ability to manipulate virtual representations of morphology, to make relative comparisons between models, and to quantitatively assess how evolutionary changes of shape result in functional adaptations.

A new species of Oikozetetes, O. mounti n. sp. is described from the upper Mernmerna Formation (equivalent to Cambrian Series 2) in the eastern Flinders Ranges, South Australia. Description of both shell morphotypes (morph A and B) from the same stratigraphic horizon favors the interpretation of a two-shelled scleritome for Oikozetetes. Identification of at least two types of halkieriid sclerite (palmates and siculates) in stratigraphic association with the Halkieria-like shells of Oikozetetes suggests that these elements are derived from the same scleritome. This provides evidence against previous suggestions that the Gondwanan species was aspiculate; the scleritome arrangement is interpreted to be similar to Halkieria evangelista Conway Morris and Peel, 1995 and supports placement in the family Halkieriidae Poulsen, 1967. Comparison of modes of accretionary growth in Oikozetetes shell morphotypes to Halkieria shells and terminal plates in modern polyplacophorans, supports a scleritome model that places shell morphs A and B in posterior and anterior locations, respectively, along the axis of the body.