The Hawkesbury Sandstone (Hawkesbury Series, Sydney Basin) on the southeastern coast of New South Wales, Australia, preserves a depauperate but important vertebrate tetrapod body-fossil record from the Early and Middle Triassic. As with many fossil sites around the world, the ichnological record has helped to shed light on the paleoecology of this interval. Herein, we investigate historical reports of a trackway pertaining to a putative short-tailed reptile found at Berowra Creek in the 1940s. Reinvestigation of the surviving track-bearing slabs augmented by archival photographs of the complete trackway, suggests that these impressions, which consist primarily of didactyl tracks (plus less common monodactyl and tridactyl traces), represent the earliest example of a swimming tetrapod found in Australia. Another isolated specimen (possibly from a nearby locality at Annangrove) appears to represent similar didactyl swim traces of a second, larger individual. Although the identities of the trackmakers are unknown, the Berowra Creek individual had an estimated body length of between ~80 cm (short-coupled) and 1.35 m (long-coupled), and produced the subaqueous trackway while travelling upslope (against the current) on a sandbar within a braided river system of the Hawkesbury Sandstone. These trackways partially resemble amphibian swim traces in the so-called Batrachichnus C Lunichnium continuum, but appear to represent a unique locomotion trace. This reanalysis of the Berowra Creek trackway provides insight into the locomotion of tetrapods of the Triassic Hawkesbury Series, which remains a poorly understood aspect of their life history.

Cardichelyon rogerwoodi is an enigmatic fossil turtle from the late Paleocene to early Eocene of North America. Previous analyses suggested affiliation with Testudinoidea, in particular the big-headed turtle Platysternon megacephalum, based on the presence of multiple musk-duct foramina and a large head. We here highlight previously undocumented characteristics for this turtle, notably the presence of short costiform processes, a rib-like axillary process, and a posterior plastral hinge. Phylogenetic analysis places Cardichelyon rogerwoodi within Testudinoidea, but the exclusion of testudinoids suggest an affiliation with Dermatemydidae. Using consilience with external data we favor placement within Kinosternoidea. Cardichelyon rogerwoodi is therefore an aberrant, hinged kinosternoid that developed in situ in North America during the Paleocene long before the arrival of testudinoids on this continent in the early Eocene.

Deinotheriidae Bonaparte, 1845 is a family of browsing proboscideans that were widespread in the Old World during the Neogene. From Miocene deposits in the Indian subcontinent, deinotheres are known largely from dental remains. Both large and small species have been described from the region. Previously, only small deinothere species have been identified from Kutch in western India. In the fossiliferous Tapar beds in Kutch, dental remains have been referred to the small species Deinotherium sindiense Lydekker, 1880, but the specimens are too fragmentary to be systematically diagnostic. Here, we describe a large p4 of a deinothere from the Tapar beds and demonstrate that it is morphologically most similar to Deinotherium indicum Falconer, 1845, a large species of deinothere, thereby confirming the identity of deinotheres at Tapar. Deinotherium indicum from Tapar is larger than other deinotheres identified from Kutch and is the first occurrence of the species in the region. This new specimen helps constrain the age of the Tapar beds to the Tortonian and increases the biogeographic range of this species—hitherto only known from two localities on the subcontinent. This specimen also highlights the morphological diversity of South Asian deinothere p4s and allows us to reassess dental apomorphies used to delimit Indian deinothere species. Lastly, we argue that by the late Miocene, small deinotheres in Kutch were replaced by the large Deinotherium indicum.

Falloaster anquiroisitus new genus new species (Asterozoa, Echinodermata) is described from the Floian (Early Ordovician) Garden City Formation of Idaho. The new taxon is known from a single small specimen. Because of weathering, remaining disk elements are incomplete. Dorsal surfaces of the ambulacral ossicles of two arms are available, one well preserved, whereas those of a third arm expose the ambulacrals essentially as they would appear in ventral view. Ambulacral ossicles were all but entirely lost on the remaining two arms.

Albeit asterozoan, F. anquiroisitus is not assignable at the class level. It is suggestive of the Asteroidea in presence of a domal disk, five abruptly tapering triangular, arched arms, and ambulacral ossicles vaulted to form a furrow. Ambulacral morphology, including the presence of very large podial pores, is unlike that of early asteroids. In addition, no adambulacral or other virgal-series derivatives are present; ambital framework ossicles are absent; a single series of enlarged, plate-like arm ossicles, one series on each side of the arm, come together at the arm midline; and the plate-like series were supported laterally by recurved ambulacral margins. Only remnants of the disk near the periphery survive, these of overall expression unlike any other echinoderm, including asterozoans. The mouth frame is unknown. Falloaster anquiroisitus is argued to represent an extinct lineage apart from the four recognized asterozoan classes, thereby joining a limited number of other problematic early Asterozoa.

UUID: http://zoobank.org/a13a5417-44b6-4ac3-90cf-9dc8fb5902bd

A new species of gopher, Gregorymys mixtecorum n. sp., is described from the Arikareean 1 (early Oligocene) of Oaxaca, southern Mexico. Phylogenetic analysis indicates that it is the sister species of G. veloxikua, which was also recently described from southern Mexico. Both species were collected from sediments of the Chilapa Formation that crop out in northwestern Oaxaca. Gregorymys mixtecorum n. sp. and G. veloxikua show differences in size and proportions that possibly reduced competition for resources, exploiting different microhabitats. Both Mexican species represent the oldest and the most southern records of Gregorymys in North America. The Mexican record of Gregorymys suggests that at least some entoptychine rodents diversified in southern Mexico or Central America, and that Geomyidae has had a wide geographic distribution in North America since the early Oligocene.

UUID: http://zoobank.org/0f4ad549-2f59-442b-87fa-5c9be0573ea4

We describe a new extinct spiny rat, Proclinodontomys dondasi n. gen. n. sp. (Rodentia, Caviomorpha, Echimyidae), represented by a noteworthy preserved skull and mandible from the early-middle Pleistocene outcrops at the coastal cliffs of SE Buenos Aires Province (Central Argentina). Phylogenetic analyses allow us to propose that the new species described here and the already known Eurzygomatomys mordax (Winge) represent a new genus closely related to the living Euryzygomatomys spinosus and Clyomys laticeps. The new genus differs from Euryzygomatomys and Clyomys by having much more procumbent upper incisors, a more developed fossa for the M. temporalis, more flared and laterally expanded zygomatic arches, frontal less markedly expanded posteriorly, jugals much deeper anteriorly than posteriorly, with the dorsal border descending more abruptly posteriorly, smaller orbital cavity, and external auditory meatus relatively smaller and slanted upward and backward. Several features of the new species reflect a higher degree of adaptation to semifossorial habits than those of E. spinosus. The origin of the semifossorial ecomorphotype within echimyids may have been triggered by the expansion of relatively open and arid environments that arose near the Miocene-Pliocene boundary. The record of this new echimyid in Central Argentina indicates that during the early-middle Pleistocene, the southern limit of the geographic range of extinct representatives of the Brazilian lineage of semifossorial echimyids extended farther south than that of their living members.

UUID: http://zoobank.org/c30ec1fe-4352-4867-a02f-e0d45c884bfe

The Microsyopidae are extinct mammals from the late Paleocene–late Eocene of North America and the late Paleocene of Europe. While results from phylogenetic analyses support euarchontan affinities, specific relationships of microsyopids to other plesiadapiforms (plausible stem primates), Euprimates (crown primates), Scandentia (treeshrews), and Dermoptera (colugos) are unresolved. An exceptionally well-preserved cranium of Microsyops annectens includes a basicranium that is generally primitive relative to that of other extinct and extant euarchontans in having: (1) a transpromontorial groove for an unreduced internal carotid artery (ICA) entering the middle ear posteromedially; (2) grooves (not tubes) on the promontorium, marking the course for both stapedial and promontorial branches of the ICA; (3) a foramen faciale that opens into the middle ear cavity, with the facial nerve exiting through a stylomastoid foramen primitivum; and (4) unexpanded caudal and rostral tympanic processes of the petrosal. The absence of any preserved bullar elements in the middle ear contrasts with that of other plesiadapiforms for which the region has been recovered, all of which have evidence of an ossified bulla. Microsyops lacks many of the specialized cranial characteristics of crown scandentians and dermopterans. The basicranial anatomy of microsyopids does not provide evidence in support of a clear link to any of the extant euarchontans, and suggests that the primitive morphology of this region in Euarchonta was little differentiated from that observed in the primitive placental mammals.

Treeshrews are small, Indomalayan mammals closely related to primates. Previously, three-dimensional geometric morphometric analyses were used to assess patterns of treeshrew lower second molar morphology, which showed that the positions of molar landmarks covary with intraordinal systematics. Another analysis used dental topographic metrics to test patterns of functional dental morphology and found that molar curvature, complexity, and relief were an effective means for examining patterns of variation in treeshrew dietary ecology. Here, we build on these analyses by adding two fossil taxa, Prodendrogale yunnanica Qiu, 1986 from the Miocene of China and Ptilocercus kylin Li and Ni, 2016 from the Oligocene of China. Our results show that Pr. yunnanica had a dental bauplan more like that of a tupaiid than that of a ptilocercid, but that the extant tupaiids, including Tupaia and Dendrogale, are more similar to one another in this regard than any are to Prodendrogale. This is contrary to our expectations as Prodendrogale is hypothesized to be most closely related to Dendrogale. Ptilocercus kylin, which has been proposed to be the sister taxon of Pt. lowii Gray, 1848, is characterized by dental morphology like that of Pt. lowii in crest and cuspal position but is interpreted to have been more frugivorous. It has been claimed that Ptilocercus has undergone little morphological change through time. Our results suggest that Pt. kylin was more ecologically distinct from Pt. lowii than previously proposed, providing a glimpse into a more complex evolutionary history of the group than had been inferred.

Conularina triangulata (Raymond, 1905), the genotype of Conularina Sinclair, 1942, is a rare, early Late Ordovician conulariid (Cnidaria, Scyphozoa; Van Iten et al., 2006) having three sides or faces instead of four (Sinclair, 1942, fig. 9; Van Iten, 1992, text-fig. 3E). Originally described from the Valcour Formation (early Sandbian; Dix et al., 2013) on Valcour Island, New York (Sinclair, 1942), C. triangulata has since been found in laterally equivalent strata of the upper Laval Formation (‘Upper Chazy’; Sinclair, 1942) in Laval, Québec, Canada (Sinclair, 1942). From this same unit and area, Sinclair (1942) erected three new, four-sided species of Conularina (C. irrasa, C. raymondi, and C. undosa), and he erected a single four-sided species (C. narrawayi) from the Ottawa Formation (now the Sandbian–Katian Ottawa Group; Dix et al., 2013) at Tétreauville (now Gatineau), Québec. Subsequently, Jerre (1994) reported the occurrence of two species of Conularina in the Upper Ordovician of Sweden. Jerre (1994) also proposed that Eoconularia? forensis Sinclair, 1946 from the Upper Ordovician Citadelle Formation (‘Quebec City’ Formation; Sinclair, 1946) in Québec City, Québec (Promontoire de Québec thrust sheet, Appalachian Humber Zone, Allochtonous Domain; Castonguay et al., 2002) is a species of Conularina.

Nanobamus macrorhinus Schoch and Milner, 2014 is a small amphibamiform temnospondyl from the early Permian Arroyo Formation of Texas. It is most readily characterized by an elongate and partially subdivided naris. This condition is superficially reminiscent of that seen in the coeval trematopids, the group to which N. macrorhinus was originally referred to under an interpretation of the holotype as a larval form. This was discounted by later workers, but the amphibamiform affinities of the specimen were not formalized until recently. The specimen has never been described in the context of its amphibamiform affinities and remains poorly characterized, never having been sampled in a phylogenetic analysis. Here we present a complete, updated osteological description of N. macrorhinus, including an improved characterization of its unique mosaic of plesiomorphic and apomorphic features and clarification of the taxon's autapomorphies. Our analysis of the taxon's phylogenetic position within Amphibamiformes shows that N. macrorhinus was recovered as diverging after basal amphibamiforms, e.g., the micropholids, and before derived amphibamiforms, e.g., the amphibamids. This is supported by the unique mixture of retained plesiomorphies, e.g., nonforeshortened postparietals and an oval choana, and apomorphies, e.g., a narrow interorbital region and slender palatal rami of the pterygoid. These results reflect the complexity of terrestrial amphibamiform diversity and provide further insight into the evolutionary history of the lissamphibian stem in terrestrial environments.

In an article by Geyer and Peel (2017, p. 288), we inadvertently coined a species-group name, Elrathia groenlandica Geyer and Peel, 2017 for a trilobite species of the superfamily Ptychopariacea. This name is a junior homonym of Elrathia? groenlandica Poulsen, 1927 and is thus invalid (ICZN Article 57.2; see International Commission on Zoological Nomenclature, 1999). We therefore propose Elrathia hensonensis new name as the replacement name for E. groenlandica Geyer and Peel, 2017. The new species name is derived from the Henson Gletscher area, North Greenland, the region where the type locality of this species is located.

Kazachostylops occidentalis Nesov, 1987b, based on partial maxilla and dentary from the upper Paleocene Zhylga locality in South Kazakhstan, is redescribed. A new phylogenetic hypothesis of Arctostylopida is proposed based on phylogenetic analysis of 26 characters and 17 taxa. Kazachostylops is recovered as a sister taxon to the Arctostylopinae, the advanced clade of Asian and North American arctostylopids characterized by pseudohypocone on upper molars and reduced trigonid of lower molars, with the ectolophid being attached labial on the trigonid. Kazachostylops differs from more basal arctostylopids (Asiostylops, Allostylops, Bothriostylops, and Wanostylops) by higher-crowned molars, M1–3 metaconule absent, m1–3 entoconid connected with ectolophid by entolophid, and m2 wider than m1 and m3. Principal component analyses of the upper and lower dentition of arctostylopids show great distinctness of Kazachostylops from other members of the group. The arctostylopid taxa are reviewed, and the new genus Enantiostylops is erected for ‘Sinostylops’ progressus Tang and Yan, 1976 from the lower Eocene of China, because of uniquely concave parastylar area on upper molars.

UUID: http://zoobank.org/a46d8f29-fd73-4e59-88dc-fcc55b12d1d3

A long hiatus encompassing most of the Eocene (end of the Ypresian to the early Priabonian) breaks up the proboscidean evolutionary history, which is otherwise documented by a rich fossil record. Only two post-Ypresian localities from West Africa (Mali and Senegal) have yielded scarce Moeritherium-like dental remains. Here, we study one of these remains from Senegal and name a new genus and species, Saloumia gorodiskii. This taxon, confidently mid-Lutetian in age, evokes Moeritherium and elephantiforms with its wrinkled enamel, lack of centrocrista, and strong lingual cingulum. However, due to its pronounced bunodonty, which departs from the bunolophodonty of both Moeritherium and elephantiforms, we cannot exclude the possibility that Saloumia documents an early experiment in dental diversity among Paleocene–Eocene proboscideans, without direct relationships with later proboscideans.

UUID: http://www.zoobank.org/0b6b83f8-817d-498c-a672-8ffa8f81a978

Materials from the localities of Araia d'Alcora in the Ribesalbes-Alcora Basin (Spain, early Miocene, Biozone C, MN4) have yielded an assemblage of erinaceids and metatherians, relatively rich for an Iberian site. The most common erinaceid is the gymnure Galerix symeonidisi Doukas, 1986, present in almost all of the studied sites. Other erinaceids in the faunal list are possibly an indeterminate species of the genera Lantanotherium Filhol, 1888 and Atelerix Pomel, 1848, in what constitutes one of their oldest occurrences in Europe. Metatherians are represented by the herpetotheriid Amphiperatherium frequens erkertshofense (Koenigswald, 1970). The material described here was partially published by Furió and colleagues in 2012. We complete it with new material from the known localities and with material from new sites. We describe for the first time the lower dentition of this taxon in this basin, thus increasing knowledge of the high variability of its decidual molars. In addition, the climatic preferences of the species A. frequens (von Meyer, 1846), which was probably less strict in its humidity requirements than previously thought, are also discussed.

The type species Placenticeras warthi Kossmat, 1895 described from the Early Cretaceous (Albian) of South India is crucial for understanding the true affinity of the genus Hypengonoceras Spath, 1922. The species description was based on a holotype and was influenced by the erroneous and misleading hand sketches of the species published in the literature. We recently inspected the type specimen archived in Geological Survey of India, Kolkata, along with one additional specimen kept in Indian Museum, Kolkata, and redescribe them in the present study.