The Middle Jurassic was a critical time in pterosaur evolution, witnessing the appearance of major morphological innovations that underpinned successive radiations by rhamphorhynchids, basally branching monofenestratans, and pterodactyloids. Frustratingly, this interval is particularly sparsely sampled, with a record consisting almost exclusively of isolated fragmentary remains. Here, we describe new material from the Bathonian-aged Kilmaluag Formation of Skye, Scotland, which helps close this gap. Ceoptera evansae (gen. et sp. nov.) is based on a three-dimensionally preserved partial skeleton, which represents one of the only associated Middle Jurassic pterosaurs. Ceoptera is among the first pterosaurs to be fully digitally prepared, and µCT scanning reveals multiple elements of the skeleton that remain fully embedded within the matrix and otherwise inaccessible. It is diagnosed by unique features of the pectoral and pelvic girdle. The inclusion of this new Middle Jurassic pterosaur in a novel phylogenetic analysis of pterosaur interrelationships provides additional support for the existence of the controversial clade Darwinoptera, adding to our knowledge of pterosaur diversity and evolution.

The family Latidae is considered to have originated in marine waters of the Tethys, and the fossil record of this group indicates a widespread occurrence of latid fishes in the past. In the Mediterranean–Paratethyan basins, the genus Lates is represented by a number of fossil species, the youngest of which have been reported from Miocene deposits of Italy and Ukraine. Here we report on Lates fossils recovered from Late Miocene (Pontian) deposits of the Shkodova Gora locality of Ukraine, with a description of a new species †Lates odessanus sp. nov. The new species bears distinct morphological traits, especially on its maxilla, premaxilla, and parasphenoid, not found in other spatiotemporally close relatives. The fossil record shows that much of the latid species diversity was lost after the Late Miocene, and the newly described species, †L. odessanus, appears to be the last known extinct representative of this group in low salinity deposits of the Mediterranean–Paratethyan basins. The only extant Lates species in the Mediterranean, L. niloticus, has survived in estuarine environments of the southern shore.

A new gyracanthid Gyracanthides riniensis is described from the Famennian (latest Devonian) Waterloo Farm Lagerstätte in the Witpoort Formation, near Makhanda/Grahamstown, South Africa. The new species is based on disarticulated remains including pectoral, pelvic, and median fin spines, endoskeletal shoulder girdle elements, and squamation patches preserved on or close to the same bedding plane. The new taxon is distinguished by having a relatively large, ornate median spine, and arrowhead-shaped tubercular ornament on the spine ridges. The species shows closest resemblance in pectoral spine proportions to Gyracanthides murrayi from the earliest Carboniferous of Australia, and in spine tubercular ornament to its Laurussian contemporary “Gyracanthus” sherwoodi. It differs in spine proportions and ornament from the older (Givetian) and younger (early Carboniferous) gyracanthids found in nearby localities.

The Paleocene deposits from the Cerrejón Formation (Colombia, South America) have provided abundant snake remains. All this material has been assigned to the giant snake Titanoboa cerrejonensis. Here, we describe six vertebrae from among the referred materials that do not correspond to Titanoboa. All six vertebrae are morphologically identical, of a similar size, and display a distinct morphology that differs from Titanoboa. This new and unnamed taxon is a large snake estimated to be around eight meters in total length. Anatomical comparisons show that these vertebrae possess certain features typical of the Palaeophiidae, a group of extinct snakes of uncertain relationships known almost exclusively from vertebrae. Among the Palaeophiidae, the new taxon resembles the more generalized forms assigned to the genus Palaeophis, but lacks the extreme aquatic adaptations that define forms assigned to the genus Pterosphenus. We regard the new taxon as an undetermined palaeophiine but do not assign it to Palaeophis as a number of features differ from that described genus. This new record expands the known diversity of aquatic snakes from the Paleogene of South America and provides a substantial new record for the paleogeographic distribution of the Palaeophiidae. The oldest records are from the Cretaceous of Africa, while Paleocene records are poorly known and restricted to Africa, North America, and Europe. The majority of vertebral forms assigned to Palaeophiidae are from the Eocene, principally from the Tethys region, with only one previous South American record coming from the Eocene of Ecuador.

The Mediterranean Basin has been subjected to important geological and paleogeographic events that have shaped the evolution of the faunal assemblages that inhabit it. Two main events can be highlighted, the closure of its eastern margin by the Gomphotherium Land Bridge, and the temporal closure of the connection to the Atlantic Basin during the Messinian Salinity Crisis. These two events shaped the diversity of the chondrichthyan assemblages of the Mio–Pliocene Mediterranean, and their consequences can be observed even in the modern faunal composition. To better understand the taxonomic and ecological composition of the Mediterranean chondrichthyan faunas between the aforementioned events, and how they affected their evolutionary dynamics, we have performed a complete systematic and paleoenvironmental study of the chondrichthyan assemblage recovered from various Late Miocene localities at the municipality of Alcoy Basin (Alicante, eastern Spain). Our analysis allowed us to recognize up to 20 taxa of sharks and rays recovered from Miocene deposits. In addition, we reconstruct the paleobathymetry of the El Muro fossil site, based on the estimation of the Oceanization Index for foraminifera, as well as by the elasmobranch fossil assemblage via weighted bootstrap analysis. We expect that this first description and study of the Miocene chondrichthyan taxa from this area of eastern Spain could help us create a comparative framework to compare these communities with other areas, as well as show the changes in the elasmobranch species that have inhabited the Mediterranean Basin during and after the Messinian Salinity Crisis.

The type specimens of eight Paleozoic vertebrate species from Ohio, U.S.A., originally described by J. S. Newberry and subsequently reposited in the Orton Geological Museum, are reviewed and illustrated photographically. They include four actinopterygian fish species from the Linton Konservat-Lagerstätte (Upper Freeport Coal; Carboniferous) in Jefferson County, Ohio, described in 1857 under the basionyms Mecolepis corrugatus (now Haplolepis corrugata), M. insculptus (synonymized as Parahaplolepis tuberculata), M. lineatus (now Pyritocephalus lineatus), and M. ovoideus (now Microhaplolepis ovoidea). One actinopterygian species, Eurylepis striolatus, a junior synonym of Haplolepis corrugata, was described in 1873 from the Linton deposit; and one chondrichthyan species, Orthacanthus gracilis, now replaced as Orthacanthus adamas Babcock, 2024, was first described by Newberry in 1875 from Linton. Lectotypes are designated from the syntypic series of M. insculptus and O. adamas. A tooth from the Linton Lagerstätte, originally described as a fish in 1857 under the basionym Rhizodus lancifer, is the holotype of the tetrapod (anthracosaur) Anthracosaurus lancifer. One Devonian sarcopterygian fish species, Onychodus ortoni, was described in 1889 from the Ohio Shale, Huron Shale Member, a Konservat-Lagerstätte occurring in Franklin County, Ohio.

Iguanodontia is a diverse clade of herbivorous ornithischian dinosaurs that were speciose and abundant during the Jurassic and Cretaceous. Although the monophyly of Iguanodontia is well supported, their internal relationships have sparked heated debate due to several phylogenetic paradigm shifts. Late Jurassic basally branching iguanodontians in particular are not well understood in terms of their systematic affinities and evolutionary relevance. Their fossil record in Europe is meager compared with North America, with only a few species currently recognized. Two taxa are currently known from the Upper Jurassic of England, the basally branching styracosternan Cumnoria prestwichii and the putative dryosaurid Callovosaurus leedsi. In the Upper Jurassic of Portugal, the styracosternan Draconyx loureiroi and the dryosaurid Eousdryosaurus nanohallucis are presently the only described basally branching iguanodontians. Here we report a new species of early diverging iguanodontian from the Upper Jurassic Lourinhã Formation of western-central Portugal. The new species is clearly distinguished from all other coeval taxa by an exclusive combination of characters that include a tibia with a cnemial crest that is directed craniolaterally and a fibular condyle that is angled at 90° with respect to the proximal epiphysis, a fibula with symmetrical proximal margins, and a reduced metatarsal I. The phylogenetic relationships of the Lourinhã iguanodontian were explored using maximum parsimony and Bayesian inference. The two analyses recover the Lourinhã iguanodontian as an indeterminate dryomorphan, with more precise affinities precluded due to the current available material. Body size is estimated between 3 and 4 meters for the holotype specimen, adding to the diversity of small ornithopods already recognized in the paleoichnological record of the Lourinhã Formation.

A new gyracanthid, Gyracanthus? jasperi, is described based on partially articulated and isolated elements from the Lower Carboniferous (Mississippian) lower Waugh Member of the Ste Genevieve Formation, at the early tetrapod site near Delta, Iowa, U.S.A. Pectoral fin spines of the new gyracanthid are characterized by the insertion on the fin spine being a half to one-third the length of the spine and maximum length:depth ratio 10:1. Ornament ridges on the pectoral fin spine converge at ≥90° along a low leading edge ridge, and ridge tubercles are oriented oblique to the ridge; the distal end of one pectoral is described using micro-computed tomography. The scapulocoracoids have an anteriorly curving bulbous apex, and a base length that is 35–40% of pectoral spine length. The procoracoid is associated with an unornamented ventral plate. A possible isolated dorsal fin spine is more symmetrical and less worn than the pectoral fin spines. Pelvic spines are dorsoventrally flattened, with oblique ridges meeting at approximately 100° proximally and 80° distally, along a smooth leading edge ridge. Scales, found on the partial articulated specimen and as isolated remains, are polyodontode with a flat base. Adults of the new taxon are estimated to have been about one meter long. Deposition was in debris flows, within a sinkhole lake most likely removed from the edge of the ocean. Other Carboniferous gyracanthids from North America are reviewed.

The Kem Kem Group of Southeastern Morocco, North Africa, is well known for theropod remains, especially isolated teeth. Here, a collection of isolated theropod teeth is assessed for diversity using a combination of linear discriminant, phylogenetic, and machine learning analyses for the first time. The results confirm earlier studies on Kem Kem theropod diversity, with teeth referred to Abelisauridae, Spinosaurinae, and Carcharodontosauridae. A single tooth is ascribed to a non-abelisauroid ceratosaur or a megaraptoran and may represent the enigmatic averostran Deltadromeus. Spinosaurine teeth are clearly differentiated by all three methodologies, whereas abelisaurid and carcharodontosaurid teeth could only be distinguished by the machine learning and phylogenetic analyses. This study shows that a combination of independent methods is most effective at providing strong evidence on theropod dental diversity in a particular assemblage, and that cladistic and machine learning analyses are the most reliable approaches to identify isolated dinosaur teeth. The methodology used here is likely to yield results in other dinosaur assemblages where isolated teeth are more abundant than body fossils.

Eutriconodonta is a diverse group of crown mammals that are known from the Jurassic and Cretaceous, mainly on the northern landmasses. Here we report a single lower molariform from the “intertrappean” deposits exposed near Anjar, in the Kutch district of the state of Gujarat, India that date to the last 259,000 years of the Cretaceous. The lower molariform of this new genus of eutriconodontan is relatively large, has three subequal, erect, lanceolated cusps, and lacks both a buccal and lingual cingulum, accessory cusps (d, e), and a vertical groove mesial to cusp b. It represents the first eutriconodontan mammal from the Cretaceous of India and the Late Cretaceous of Gondwana, and is the globally youngest record of this group. The results of a cladistic analysis support placement of the new Indian taxon among the Eutriconodonta, possibly more closely allied to triconodontids than to other groups. This new genus of eutriconodontan is the tenth named mammalian species known from the Late Cretaceous of India and the first relatively large-bodied faunivore. This record shows that the Eutriconodonta had a broader temporal and geographic distribution than previously thought and highlights the importance of continued paleontological exploration on the Indian subcontinent.

After about a century, the skull of the holotype and sole specimen of Arambourgia gaudryi from the Eocene of Quercy (France) is here redescribed. Its interest resides in its extreme morphology, such as its very small skull and altirostral condition, that raises questions about its maturity, taxonomic validity, and paleoecology. In order to reveal previously hidden anatomical details, we used computed microtomography (µCT-scan) data to digitally extract the bones of the cranium and mandible, as well as the endocranial structures. Here, we update the osteological description of A. gaudryi, outlining new characters and re-evaluating anatomical details. Comparing it with ontogenetic series of extant crocodylians, we confirm that the specimen is a mature individual of a dwarf species with pedomorphic features. Our phylogenetic analyses indicate that A. gaudryi is an alligatorine. Comparisons with other small alligatoroid taxa show that it is indeed a valid species. The depositional environment of the finding site suggests a continental context with a karstic network. Taking this into account, together with its peculiar anatomy, we propose that A. gaudryi was a semi-terrestrial animal occupying an ecological niche similar to that of extant juvenile or dwarf crocodylians. Finally, we discuss the current knowledge of the paleobiogeography of Alligatoroidea in Europe during the Paleogene. Arambourgia gaudryi was likely part of a group of small early globidontans that arrived in the Old World, probably from North America, around the end of the Paleocene and that dispersed to at least four localities of the ancient European archipelago.

The giant tortoises of the Galápagos Archipelago influenced Darwin's early thinking on transmutation and now constitute a famous example of island-based speciation and evolutionary dynamics. Questions regarding their evolutionary origin still exist and include whether their giant size evolved before or after the lineage arrived in the Galápagos from the South American continent. Here we present new evidence supporting the ‘before’ hypothesis based on previously reported fossil specimens from the Late Pleistocene of Ecuador. Despite the isolated and fragmentary nature of these tortoise fossils, phylogenetically informative features are preserved. A tip-dated phylogenetic analysis recovers the Ecuador form as the sister taxon to the Galápagos lineage, thus supporting the existence of a closely related, giant tortoise population at approximately the same time and place that the Humboldt Current is thought to have carried the ancestral Galápagos tortoise to the archipelago. The phylogeny also raises the possibility that the same evolution of continental gigantism also facilitated the dispersal of South American tortoises into the Caribbean Basin where they diversified before succumbing to Holocene extinction.

Gorgonopsia is an iconic group of saber-toothed, carnivorous therapsids. They have a rich fossil record in the Karoo Basin of South Africa, but are also relatively common components of coeval Malawian, Tanzanian, Zambian, and Russian assemblages. Phylogenetic analyses have demonstrated that African gorgonopsians form a monophyletic subclade distinct from their Russian relatives, which all fall out near the root of the cladogram, thus suggesting a northern hemisphere origin for the clade as a whole. Surprisingly, recent research has demonstrated that a species of Inostrancevia, a genus previously recorded solely in Russia, occurs in the upper Daptocephalus Assemblage Zone of the Karoo Basin, perhaps the result of immigration following the demise of endemic rubidgeine gorgonopsians in the lower subzone of that unit. Here we describe a large, isolated gorgonopsian premaxilla from a bone-rich, conglomeratic interval at the base of the Usili Formation of Tanzania's Ruhuhu Basin. Based on its stratigraphic position and fossil content, this unit likely correlates with the Cistecephalus Assemblage Zone. The premaxilla can be confidently referred to the genus Inostrancevia on the basis of its four incisors, a feature unique to Inostrancevia among gorgonopsians. In contrast to the disjunct distribution of inostranceviines and rubidgeines in the uppermost Permian of South Africa, the Tanzanian Inostrancevia likely overlapped with large-bodied rubidgeines such as Dinogorgon and Rubidgea.