Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partial skull (cranium and mandible), the atlas-axis complex, additional cervical vertebrae, caudal vertebrae, an ilium, and limb elements. The basioccipital and atlas intercentrum are pathologically deformed, probably due to an osteomyelitic infection. Two potential autapomorphies were found in the mandible: (1) the alveolar margin at the symphysis is laterally expanded with the rostral-most alveoli being markedly procumbent and situated along the lateral margins of the dentaries; and (2) the ventral midline at the symphysis is produced into a prominent wedge-shaped platform indented by numerous irregular pits. Lagenanectes richterae, gen. et sp. nov., also shows a number of typical elasmosaurid traits, including a longitudinal lateral ridge on the cervical vertebral centra (although a ventral notch is absent) and teeth with oval cross-sections. Lagenanectes richterae, gen. et sp. nov., is one of the best-preserved plesiosaurians from the Lower Cretaceous of Europe.

A new specimen, referred to the notharctid primate Notharctus tenebrosus, is described from the middle Eocene of eastern Nevada. The material consists of the upper and lower jaws with most tooth loci represented, including rare representation of relatively unworn upper incisors. The completeness of the specimen permits a restoration of the spatial relationships of the anterior teeth, demonstrating that there was a small zone of interproximal contact between the upper central incisors. The relatively unworn upper incisors also indicate a unique cropping mechanism in notharctids not seen before in the group. The orientation of the cropping edges on the upper central incisors changed progressively with tooth wear, implying a shift in function and/or food properties over the course of dental senescence. The provenience of the specimen highlights the wide geographic distribution of this extinct primate species.

The bone tissue of femur, rib, and gastralia from three different individuals of the Middle Triassic pseudosuchian Batrachotomus kupferzellensis from southern Germany is studied. The femoral bone tissue comprises laminar fibrolamellar bone tissue throughout and is stratified by three annual growth cycles, indicating that the individual died early in its fourth year of life, at which time it had reached 87% of maximum known femur length. Thus, compared with most other Pseudosuchia (e.g., phytosaurs, aetosaurs, and most crocodylomorphs, including marine taxa), Batrachotomus achieved its large body size in a very short time by fast, although interrupted, growth and not by protracted longevity. Such fast growth as well as the organization of the tissue is similar to the condition observed in ornithodirans. The pseudosuchians Effigia and Postosuchus also show fibrolamellar tissue, but vascular density is lower when compared with Batrachotomus and dominated by a longitudinal organization of primary osteons. The rib and gastralium of Batrachotomus both show an inner spongious organization surrounded by a ring of compact, avascular, highly organized parallel-fibered and/or lamellar bone largely covered by short fibers. Maximal growth cycle count in the proximal rib sample suggests an age of at least 11 years for this individual with a reduction of growth rate after the sixth cycle.

We describe the first partially articulated specimen of Ophisaurus (Anguimorpha, Anguinae) from the middle Miocene (MN 7) locality Öhningen, in Germany. This is the first time that the preservation of a specimen of Ophisaurus allows cranial and postcranial elements to be allocated to the same species. High-resolution X-ray computed tomography reveals a completely preserved parietal, identifying the specimen as belonging to the species Ophisaurus holeci. This species was previously known on the basis of frontal and parietal bones from the early Miocene of the Czech Republic and Germany. The specimen from Öhningen also preserves the right pelvic girdle, consisting of a well-preserved ilium and partially preserved pubis and ischium; a limb is not preserved. Within fossil Anguinae, there is only one specimen of Ophisaurus in which a similarly preserved pelvic girdle is present. This specimen is from the middle Miocene of Slovakia, and the morphology of its pelvic girdle is revised here. The morphology of the pelvic girdles of both these Miocene specimens is very similar to that of Ophisauriscus quadrupes, a possible anguine from the middle Eocene of Germany, a form that retains small limbs. The anatomy of the pelvic girdles of all three fossil lizards and comparisons with those of extant limbed and legless lizards indicates that the two Miocene anguines studied here may have possessed small, but functional limbs.

This paper describes the cranial morphology of Anosteira maomingensis, a turtle of the clade Pan- Carettochelys, based on a skull that is part of a more complete specimen from the middle-upper Eocene Youganwo Formation of Maoming, Guangdong Province, China. The cranial data of An. maomingensis were included in a phylogenetic analysis of pan-carettochelyids, one that was complemented with new codings and characters and also including cranial and non-shell postcranial characters of Kizylkumemys schultzi (Late Cretaceous of Uzbekistan). It also included characters of vertebral scutes of pan-carettochelyids based on a newly proposed nomenclature of vertebral scutes for this group. The result of our phylogenetic analyses supports a recently proposed hypothesis of probable paraphyly of Anosteirinae, Kizylkumemys, Anosteira, and Allaeochelys. In addition, our study summarizes data on cranial morphology of pan-carettochelyid turtles and discusses some aspects of their evolution.

Fossil bovids are described from the late Pliocene site of Ledi-Geraru, mainly from the Gurumaha and Lee Adoyta sedimentary packages (2.8–2.6 Ma). Finds include taxa already known from the slightly older Hadar Formation, such as the buffalo Ugandax coryndonae, the bongo-like Tragelaphus rastafari-nakuae lineage, an alcelaphin resembling Parmularius pachyceras, and a large impala. Differences from Hadar include the abundance of Kobus sigmoidalis, the absence of K. oricornus, and the presence of Tragelaphus gaudryi and probably also Menelikia lyrocera. The fossil bovids from Ledi-Geraru are mainly comparable to those known from contemporaneous assemblages in the Turkana Basin. Menelikia and T. gaudryi are characteristic of the Turkana Basin, and these are probably their first records from the Afar. A new species of Beatragus is also named. A well-preserved skull and skeleton of a fossil wildebeest from the Ogoyta sediments (<2.4 Ma) bears a mosaic of advanced and conserved traits that illuminate the evolution of the Connochaetes clade prior to the divergence of its two extant species. Taxonomic abundance, as well as functional analyses of postcranial elements, indicates that the ancient landscape at Ledi-Geraru was primarily made up of open habitats such as seasonal grasslands, with minor components of woodlands and wetlands. This contrasts with most localities from the Hadar Formation, which record more covered habitats. Comparisons with older Afar faunas indicate that environmental changes to drier and more open habitats were part of a long-term trend that goes back to at least 4 Ma, if not earlier.

The Guadix-Baza Basin (Granada, southern Spain) represents one of the best continental records from the late Miocene to the middle Pleistocene in western Europe, but stratigraphic gaps are present in the early Pliocene due to the scarcity of sites from this time. In this article, rodent fossils from the locality of Baza-1 are described, providing new information on a time interval that was previously poorly known. The assemblage includes representatives of the genera Ruscinomys, Apocricetus, Stephanomys, Apodemus, Castillomys, Paraethomys, Occitanomys, Eliomys, Debruijnimys, and Trilophomys, an association that indicates an early Ruscinian age (MN14). A paleoecological analysis indicates that the Guadix-Baza Basin landscape during the early Pliocene was dominated by open herbaceous habitat under warm and dry climatic conditions. Our results contribute to the continuity of the stratigraphic record from the Betic Mountain range.

The presence of the atlas rib in Archaeopteryx is reported for the first time. The morphology and position of this bone in Archaeopteryx generally retain the plesiomorphic conditions for archosaurs. The reduction in robustness of the atlas rib is an evolutionary trend apparent in Theropoda and may be associated with the change in the site of origin of the subvertebral muscle from the atlas rib to the anterior cervical centra. The ansa on the atlas in some extant birds, widely regarded as a remnant of the atlas rib, is morphologically and topologically different from the atlas rib in other archosaurians, including Archaeopteryx, suggesting that the former structure might not be homologous with the atlas rib.

The paleobiogeographic significance of continental Africa during the middle and Late Cretaceous is not well understood, in part due to incomplete sampling from large portions of the landmass during these intervals. Intensified field efforts in the Galula Formation exposed in southwestern Tanzania have revealed a diverse vertebrate fauna, including the novel titanosaurian Shingopana songwensis, gen. et sp. nov., described herein. Based on a left angular, cervical vertebrae, cervical and dorsal ribs, a left humerus, and a partial left pubis, Shingopana exhibits morphology indicating affinities with the Late Cretaceous aeolosaurine titanosaurians of South America. The bulbous expansion of the cervical vertebral neural spine is similar to the condition in Bonitasaura salgadoi, Overosaurus paradasorum, and Trigonosaurus pricei. The dorsal ribs of Shingopana also present proximal anterior and posterior flanges that previously were proposed to be unique to Overosaurus. Furthermore, Shingopana is diagnosed by a divided spinoprezygapophyseal lamina in the middle-to-posterior cervical vertebrae. Parsimony and both uncalibrated and tip-dated Bayesian phylogenetic approaches support Shingopana as the first African titanosaurian that is closely related to aeolosaurines. Comparisons with other African titanosaurians, such as the co-occurring Rukwatitan bisepultus and geographically proximate Malawisaurus dixeyi, suggest that southern African forms represent diverse taxa rather than forming a monophyletic group. Moreover, southern African forms exhibit stronger affinities with South American clades than with representative northern African form, suggesting that tectonically driven separation of the two landmasses may have influenced the development of progressively isolated southern African faunas throughout the Cretaceous.

Chaohusaurus is one of the earliest-branching ichthyosauriforms, but its cranial anatomy remains poorly known due to the lack of well-preserved material. Here, three nearly complete and well-preserved skulls of C. chaoxianensis are described, revealing new information on the cranial anatomy of the species. The prefrontal-postfrontal contact is clearly present in C. chaoxianensis, unlike in Cartorhynchus and basal Hupehsuchia. The squamosal and postorbital participate in the margin of the upper temporal fenestra as in most basal ichthyosauriforms. The postorbital region is narrow, with a deep ventral embayment representing an incomplete lower temporal fenestra. Three-dimensional preservation revealed that the posterior cheek region curves and faces almost posteriorly, whereas the orbit is directed slightly dorsally rather than strictly laterally. The cranial morphology of Chaohusaurus confirms the suggestion that the elongation of the nasal and posterior relocation of the external naris preceded snout elongation in ichthyosauriforms.

A new genus and species of pycnodontiform fishes, Grimmenodon aureum, from marginal marine, marinebrackish lower Toarcian (Harpoceras exaratum ammonite subzone) clay deposits of Grimmen in northeastern Germany is described. The single specimen represents a diagnostic left prearticular dentition characterized by unique tooth arrangement and ornamentation patterns. Grimmenodon aureum, gen. et sp. nov., is the second unambiguously identified pycnodontiform species from the Early Jurassic, in addition to Eomesodon liassicus from the early Lower Jurassic of western Europe. We also report an indeterminate pycnodontiform tooth crown from the upper Pliensbachian (Pleuroceras apyrenum ammonite subzone) of the same site. The material expands the Early Jurassic range of pycnodontiforms significantly northwards and confirms their presence before and immediately following the onset of the Toarcian Oceanic Anoxic Event (T-OAE) in the marginal marine ecosystems south of the Fennoscandian Shield. Moreover, the new records indicate that the Early Jurassic diversity of pycnodontiform fishes was greater than previously assumed and probably equaled that of the Late Triassic. Therefore, it is hypothesized that the Triassic-Jurassic mass extinction event did not affect pycnodontiform fishes significantly. Micro-computed tomography was used to study the internal anatomy of the prearticular of Grimmenodon aureum, gen. et sp. nov. Our results show that no replacement teeth were formed within the tooth-bearing bone but rather were added posteriorly to functional teeth.

The cranial morphology of the oviraptorosaurian Avimimus portentosus is described based on a new specimen, one that includes bones such as the nasal and the jugal, which had not been available or only incompletely preserved previously. The left and right nasals are fused together as in oviraptorids. Morphology of the jugal, which is not fused with the quadratojugal, and the postorbital indicate that the infratemporal fenestra is completely separate from the orbit, not confluent with the latter, as inferred previously. The left and right dentaries are fused together without a trace of suture. Such newly available information indicates that the skull of Avimimus is not as ‘avian’-like as inferred in previous studies. Rather, it shows a mixture of plesiomorphic and derived character states observed in Oviraptorosauria, consistent with an intermediate phylogenetic position of this dinosaur between Early Cretaceous basal oviraptorosaurians and the diverse clade of Caenagnathoidea.

Madtsoiidae is a speciose family of extinct snakes that achieved a wide Gondwanan and trans-Tethyan distribution by the Late Cretaceous, surviving until the late Pleistocene. Gigantophis garstini, the first and largest described madtsoiid, was recovered from the upper Eocene of Fayum, Egypt. The 20 vertebrae that constitute the syntype have only received brief description, hindering the referral of specimens to this taxon and our understanding of madtsoiid interrelationships in general. A detailed redescription of the syntype material demonstrates the validity of Gigantophis, based on two autapomorphies (including a strongly depressed neural canal in posterior trunk vertebrae) and a unique combination of characters. Referred material from the lower Paleocene of Pakistan differs significantly, and we restrict Gigantophis to the middle—late Eocene of North Africa. Using a model of morphological variation in extant snakes, we estimate that Gigantophis was 6.9 ±0.3 m long. A phylogenetic analysis using the largest sample of putative madtsoiids (20 operational taxonomic units) and a revised and augmented matrix (148 characters) places Gigantophis as sister taxon to the latest Cretaceous Indian snake Madtsoia pisdurensis. Whereas our topology might suggest that a dispersal route was present between India and North Africa in the latest Cretaceous—early Paleogene, an evaluation of putative dispersal routes leads us to conclude that the paleobiogeography of Madtsoiidae is best explained by a poorly sampled, earlier widespread distribution in Africa, Indo-Madagascar, and South America. In contrast, latest Cretaceous madtsoiid occurrences in Europe might be explicable by trans-Tethyan dispersal from Africa across the Apulian Route.

This paper redescribes the holotype skull of the aristonectine elasmosaur Morturneria seymourensis from the upper Maastrichtian of Seymour Island, Antarctica. This description supports the validity of the genus Morturneria, distinct from the genus Aristonectes from Chile and Argentina. The paroccipital process of Morturneria is plesiomorphic, similar to Alexandronectes and unlike the autapomorphic occiput of Aristonectes. The palate of Morturneria is autapomorphic in possessing a strongly developed midline keel. The cranium of Morturneria is about 60% complete and preserves the anterior skull roof and palate; both regions were previously unknown in any aristonectine. The combination of the Morturneria holotype and recent research on other aristonectines allows the first confident cranial reconstruction of an aristonectine elasmosaur. The cranial anatomy of both Morturneria and its close relatives is derived relative to all other plesiosaurs, possessing a novel suite of dental and oral cavity adaptions. The suspensorium extends far behind the occipital condyle, and the jaw is long and hoop-like; together these features allowed a large gape and oral cavity volume. The palate of Morturneria is strongly keeled, forming arched lateral oral chambers that further increased oral cavity volume. The dentition of Morturneria is similar to that of Aristonectes, and all share autapomorphic interlocking combs of needle-like teeth that occluded outside the mouth and did not meet tip to tip. The upper and lower dentition formed an oral battery that may have functioned like a sieve in straining food particles from substrate ejected from the oral cavity. We theorize that this highly derived suite of adaptations is convergent with extant gray whales and archaic mysticetes and hypothesize that it functioned similarly in sieve feeding following suction. This is the first identification of whale-like filter feeding in any marine reptile, a condition once claimed to be anatomically impossible.

A new taxon of neosuchian crocodyliform, Deltasuchus motherali, gen. et sp. nov., is described on the basis of a partial skull recovered from the Arlington Archosaur Site within the Upper Cretaceous (Cenomanian) Woodbine Formation of north-central Texas. This productive locality represents a delta plain ecosystem preserving a diverse coastal fauna, including lungfish, turtles, dinosaurs (ornithopods and theropods), and crocodyliforms. Prior to this discovery, the only identified crocodyliforms from the Woodbine Formation had been the longirostrine taxa Terminonaris and Woodbinesuchus. This new taxon is differentiated from other known crocodyliforms by the presence of dual pseudocanines on both the dentary and maxilla; anterior and posterior rami of jugal comparable in depth; anterolaterally facing margin on the dorsal portion of the postorbital; contact between the descending process of the postorbital and the ectopterygoid; and a large, deep fossa on the ventral surface of the quadrate. Phylogenetic analysis recovers D. motherali as the sister taxon to Paluxysuchus newmani from the Lower Cretaceous Twin Mountains Formation of Texas. This clade lies within Neosuchia basal to Goniopholididae Eusuchia. The associated cranial elements of this new crocodyliform represent a large, broad-snouted individual, an ecomorphotype often associated with the semiaquatic ambush predator niche in this clade, and one not previously reported from the formation.

Isolated teeth from the extinct hybodontoid Reticulodus synergus Murry and Kirby are known from Upper Triassic strata of Revueltian age in Arizona, Utah, and New Mexico, U.S.A. Here, we provide evidence for ontogenetic heterodonty in Reticulodus based on a reappraisal of the type and newly discovered material from the Upper Triassic Bull Canyon Formation in east-central New Mexico. We reexamined the ∼4000 specimens of the type series and measured representative teeth (n = 88) for mesiodistal length, crown width, and crown height. Reticulodus exhibits moderate monognathic heterodonty. We then assigned almost all teeth to one of three morphotypes (I–III) defined by ratios of crown width to mesiodistal length, with morphotype I being the most equilateral and morphotype III the most elongate. A fourth morphotype (IV) possesses very low crown width to mesiodistal length ratios and is tentatively considered as posterolateral in position. Adult teeth measure 1–10 mm long, with apical surfaces ornamented with numerous reticulations, crenulations, and pits, and appear subrounded, rectangular, or hexagonal in apical view—these teeth probably enabled a durophagous diet. Juvenile teeth measure approximately 0.7–2 mm in length, exhibit greater variation in crown shape than do adult teeth, and possess a clutching-type dentition that would facilitate the capture and consumption of softer-bodied organisms. The dentition thus transitioned from a clutching-type in juveniles to a grinding-type in adults, which would have allowed both adults and juveniles to occupy the same habitat and suppressed intraspecific competition between the two age groups.

We describe a new caviomorph rodent, Cavia cabrerai, sp. nov. (Caviidae, Caviinae), from the upper levels of Andalhuala Formation (San Fernando Norte locality, Catamarca Province, northwestern Argentina), which represents the oldest fossil record of the genus. The new species differs from extant and extinct species of Cavia by a unique combination of characters: large size, proportionally anteroposteriorly elongated molars, slightly anteroposteriorly compressed prisms, relatively shallow primary lingual flexids, abundant cement in the lingual flexids, and anterolingual widening of the second crests of cheek teeth. A phylogenetic analysis indicates that Cavia cabrerai, sp. nov., is the sister taxon of extant Cavia species and displays dental characters more plesiomorphic than the latter. Some characters of C. cabrerai, sp. nov., namely, compression of prisms and depth of flexids, are morphologically intermediate between the related extinct Caviinae Palaeocavia and the extant species of Cavia. An ash bed dated at 4.72 ± 0.08 Ma that overlies the fossiliferous level of the new material supports the presence of Cavia close to the Miocene-Pliocene boundary. The origin of Cavia may have been triggered by the expansion of relatively open and arid environments that arose near the Miocene-Pliocene boundary.