Reported here is the discovery of a new mammal from the middle Paleocene of the Ouled Abdoun phosphate basin, Morocco. Hadrogeneios phosphaticus, gen. et sp. nov., is described based on dental and gnathic specimens. Comparative dental anatomy and CT scan observations support stem relationships to paenungulates. The cladistic analysis relates Hadrogeneios to paenungulatomorphs, especially based on the shared morphotypic condition of a dilambdodont ectoloph linked to inflated stylar cusps. Within the Paenungulatomorpha, Hadrogeneios is plesiomorphic not only with respect to crown paenungulates, but also to Abdounodus and Ocepeia, making it the basalmost known paenungulatomorph. Hadrogeneios, on the other hand, displays a peculiarly specialized mandibular symphyseal region (mentum), which is enlarged and raised high above the cheek teeth, and bears at its apex small incisors that are innervated and vascularized by a peculiar long and thin dorsal canaliculus. This is tentatively interpreted as a plier-like dental apparatus specialized for enhanced oral gripping function of the food, with increasing grip strength or enhanced grip precision. A composite reconstruction of the lower jaw of Hadrogeneios phosphaticus, based on 3D modeling from CT scans, is provided. Hadrogeneios, Abdounodus, and Ocepeia, all from the same Ouled Abdoun Paleocene phosphate levels, are the very rare witnesses of the first evolution and diversification of the endemic African ungulates phylogenetically preceding the modern paenungulate orders.

Percrocutoids are a group of Old World Neogene feliforms whose dentition evokes the adaptations shown by the most evolved forms of Pleistocene hyenas. This paper analyzes the ecomorphology of percrocutoid hyenas based on postcanine dentition from a multivariate metric perspective. Taking non-percrocutoid hyaenids as a reference, species of the genus Percrocuta and some species of the genus Dinocrocuta show a clear convergence with the transitional durophagous morphotypes and fully developed bone-crackers. In contrast, most Dinocrocuta species with increasing size develop very sectorial dentitions showing a clear convergence with the cursorial meat and bone-crackers hyaenids, such as those of the genus Chasmaporthetes. Through geological time, percrocutoids modified their upper dentition to a greater degree than standard hyaenids, while the opposite is observed for the lower dentition.

The hind limb of the lectotype of Alectrosaurus olseni is described in comparison with other tyrannosauroids. In addition to the autapomorphies described for Alectrosaurus by previous workers, the taxon possesses a specialized pes, where the distal condyles of the metatarsals and most phalanges are strongly elevated beyond the dorsal and ventral surfaces of the shaft of each bone, described here as the ‘pediculate’ condition. In comparison with the lectotype, previously reported Alectrosaurus and Tyrannosaurus bataar material from the Turonian of Uzbekistan, and fossils from the Kyzylkum Desert, are not referable to Alectrosaurus. A partial skull from the Iren Dabasu Formation is not referable to A. olseni because of the lack of shared diagnostic bones between it and the lectotype. Several features are shared between the skull, the holotype of Raptorex, and an isolated juvenile T. rex lacrimal, to the exclusion of other derived tyrannosauroids.

A new species of Eusthenodon from the Upper Devonian (Famennian) Catskill Formation was collected from associated talus blocks excavated during road construction along the northbound lanes of U.S. Route 15/Interstate 99 near Trout Run in Lycoming County, Pennsylvania, U.S.A. The new species is represented by isolated or partially articulated cranial bones, an anocleithrum, and body scales from several individuals. The new discovery is the second species of Eusthenodon described from the Catskill Formation after Eusthenodon bourdoni, a species found only at the Cogan House Exit Ramp locality, north of and up section from the Trout Run site. The new species is of a larger size category and exhibits qualities that distinguish it from E. bourdoni including a contact between posterior supraorbital and lacrimal bones that excludes the jugal from the orbital margin and scales with an ornamental field incised by radiating grooves. The clarity offered by the Catskill Formation Eusthenodon species informs an historical review of reports on Eusthenodon occurrence that suggests a polydemic but not cosmopolitan distribution of the taxon. A phylogenetic analysis of Tristichopteridae is presented that includes the new species presented here. The Eusthenodon species at Trout Run is the fifth tristichopterid species described from the Catskill Formation and all five are found to belong to a highly nested clade of largely Famennian tristichopterids. With a growing fauna that additionally includes rhizodontids, dipnoans, holoptychiid porolepiforms, megalichthyids, and limbed tetrapodomorphs, the Catskill Formation of Pennsylvania continues to be an important focus for the study of Late Devonian sarcopterygian evolution.

Pelecanus paranensis sp. nov., a new pelican (Aves, Pelecanidae) from the marine Upper Miocene Paraná Formation, which crops out in the Province of Entre Ríos, Argentina, is described. This record constitutes the first report of a fossil pelican from Argentina and the southernmost from South America. The holotypical specimen consists of a very large and nearly complete pelvis, which is characterized by having the cristae iliacae dorsales continuous throughout its entire length and a large foramen acetabuli. The U-shaped morphology of the postacetabular section of the pelvis of the new species as well as the wide incisura sutura iliosynsacralis, allow to infer its phylogenetic position within the New World pelican species clade, showing a close relationship with the clade (P. occidentalis + P. thagus). A probable transAtlantic dispersal route for the ancestor of the New World pelicans is thus inferred. The inland Paranaense Sea, which flooded the South American Chaco-Paraná basin during the mid-Neogene, is proposed as a south-north pathway for ancestral forms of the clade (P. occidentalis + P. thagus). These regressive marine paleoenvironments of the Late Miocene may have acted as the evolutionary driver for the transition of pelican species from brackish or freshwater habitats to those inhabiting strictly marine coastlines.

Two previously studied specimens of Gansurhinus qingtoushanensis are restudied, accompanied by the description of a relatively complete skeleton from the Lopingian Naobaogou Formation of Nei Mongol, China. The new skeleton represents an immature individual of a new species of Gansurhinus, which can be diagnosed by the choana position posterior to the premaxillary teeth, maxillary tooth position numbers of tooth row 5 is about half of tooth row 4, and length of row 5 is much shorter than length of tooth row 4. IVPP V12026 from the Naobaogou Formation is referred to the new species. Gansurhinus is distinguished by a diastema on the upper jaw, five rows of teeth on maxilla and dentary, teeth on the multiple tooth-rowed region bearing cusp-like emargination on the crown, lacking dental tooth wear. The following features could be the diagnostic characters of the genus or autapomorphies of the new species: ectopterygoid present; adductor fossa short relative to the length of lower jaw, with small contribution of surangular to posterolateral border; trapezoidal coronoid eminence with nearly straight dorsal margin; and foramen intermandibularis caudalis absent. Gansurhinus is more closely related to Rothianiscus than Moradisaurus, supporting previous analyses. This study further confirms recent work suggesting that the moradisaurine clade is more diverse than currently recognized.

Described in 1858, Trematospondylus macrocephalus is one of the earliest established plesiosaur taxa. However, despite being historically significant, the taxon disappeared from the literature shortly after its initial description and has not been mentioned for over a century. Thus, it has never been properly assessed. The holotype comprises seven vertebrae, including a supposed sacral vertebra and caudal vertebrae. The specimens were collected from the Lochen mountain massif near Balingen in southwestern Germany and derive from the Dentalienton Formation. As such, they are most likely early Bathonian (Middle Jurassic) in age. Here, we provide a thorough redescription of the material, illustrate it, and assess its phylogenetic affinities through a parsimony analysis. Our results show that T. macrocephalus shares characters with members of the Rhomaleosauridae, including, for example, the length-height ratio of the caudal centra as well as the placement of caudal ribs and hemapophyseal facets. Rhomaleosaurid affinities of the material are likewise supported by our phylogenetic analysis. Comparisons further indicate that the taxon belonged to large-bodied members of the clade, with a body length similar to that of Rhomaleosaurus. Even though the material does not enable Trematospondylus to be properly diagnosed, thus making it a nomen dubium, it still adds to the rare Middle Jurassic record of rhomaleosaurid plesiosaurs. At the same time, it enhances our knowledge of the plesiosaur taxic diversity during the pre-Callovian Middle Jurassic, which has been very limited.

The South American horned frogs or ‘escuerzos’ (Ceratophryidae) are among the best-known neobatrachians and comprise the genera Chacophrys, Ceratophrys, and Lepidobatrachus. Their relatively rich fossil record, which dates back to the Late Miocene and is largely concentrated in the Argentinean Pampas, consists mostly of variably complete cranial remains and comparatively few, mainly isolated, postcranial bones of Ceratophrys, whereas only three specimens of Lepidobatrachus are known. Here we describe two extra-Pampean ceratophryid records from the Upper Miocene–Lower Pliocene of Huayquerías del Este, Mendoza Province, Argentina, including Lepidobatrachus dibumartinez sp. nov. based on a well-preserved articulated skeleton. The new species is part of the stem of Lepidobatrachus and is diagnosed on the basis of several cranial and postcranial traits, including a large kite-shaped dorsal dermal shield. The new taxon sheds light on the evolution of a dorsal shield in the group, as well as on their paleobiogeographic history, adding support to the hypothesis of a broader ancestral distribution of Lepidobatrachus, whose diversification might have been triggered by the Late Miocene marine introgression of the Paranaense Sea. Also, it indicates that the prevalent climatic conditions during the Early Pliocene in western Argentina were much warmer and less dry than today. Finally, we discuss the potential value of the new records in calibrating the time-tree of Ceratophryidae.

A metatarsal IV from a hitherto unknown endemic small-bodied styracosternan is described from uppermost Maastrichtian strata of NE Spain, part of the Ibero-Armorican island of the Late Cretaceous European Archipelago. This element is unique among the fourth metatarsals of all other ornithopods in combining the greatly elongated proportions of basally branching members of the clade with the prominent medial flange seen in other styracosternans. This specimen becomes the holotype of a new genus and species. Histological data indicate that this individual was a late subadult at the time of death, but not far from reaching somatic maturity. By analogy with the elongate metatarsals of lightly built, small-bodied cursorial ornithopods, it is likely that this animal was also capable of rapid locomotion. This is consistent with the differential distribution of intense bone remodeling in metatarsal IV, likely resulting from biomechanical stress produced during rapid hindlimb propelling. Notably, this styracosternan represents an exception to the mediportality and large body size that characterize all other members of the clade. The elongation of metatarsal IV, inferred cursoriality, and small body size constitute a case of evolutionary convergence with the distantly related non-iguanodontian ornithopods and dryosaurid and elasmarian iguanodontians. Unlike other regions of the world where, during the latest stages of the Cretaceous, the small-bodied cursorial herbivore ecological niche was represented by non-iguanodontians and nonhadrosauriforms, in the Ibero-Armorican island this niche was likely occupied by a styracosternan.

Squamate faunas from the lower Eocene of Europe are rare. A newly discovered lower Eocene (MP 10–11) Cos locality in southwestern France has yielded an assemblage of anguimorph lizards that sheds light on the early evolution of this group. Among them is a new glyptosaurine lizard Sullivania gallica gen. et sp. nov., based on frontal material with a unique pattern and distribution of polygonal osteoderms that is distinct from that of the middle and late Eocene Placosaurus from France. It slightly resembles the stratigraphically older glyptosaurine Gaultia silvaticus from the earliest Eocene of North America, but differs from it in several aspects. Although fossils of some members of Glyptosaurinae (sensu this paper; Glyptosaurini in previous taxonomies—Glyptosaurinae is returned to the family level originally proposed by Marsh) have been documented rarely from the middle and mainly from the late Eocene of Europe, they are virtually unknown from the lower Eocene. One isolated osteoderm is referred only to Anguioidea indet. This specimen resembles osteoderms seen in Anguinae, provided that the absence of tuberclulate ornamentation is not caused by abrasion. Varanoids are represented by an isolated frontal referred to Palaeovaranidae indet. It possesses a complex ornamentation composed of mounds on the dorsal surface. A maxilla is identified as an indeterminate varanoid based on the plicidentine infolding along the bases of the preserved teeth. Although incomplete, this Cos lizard assemblage is an important and rare discovery that provides a glimpse into the ecosystems and paleobiodiversity of the lower Eocene in western Europe.