Porolepiform scales from the Lower Devonian of the Holy Cross Mountains, Poland, described from the ‘placoderm sandstone’ of the Daleszyce area, are revised. The aim of the present article is to organize the recently collected, but not formally described, porolepiform material from the Holy Cross Mountains, as well as specimens from erratic boulders collected near Gdynia (northernmost Poland), which can be referred to Porolepis. Previously collected and new material was found to contain at least two sarcopterygian taxa: Porolepis and Heimenia. Based on morphological and histological features, the described material has been divided into two scale assemblages. The first, which is assigned to Porolepis, possesses cosmine cover on the entire exposed area; in the second, assigned to Heimenia, the cosmine cover is reduced or absent. These features prove to be stable regardless of the position of the scale on the body and thus are taxonomically informative.

A new fossil fish, Vachalia moraviensis, gen. et sp. nov., is described based on a single articulated specimen collected from lower Oligocene deposits exposed in the vicinity of Kelč, Czech Republic. The morphological analysis of the specimen reveals a series of features that unambiguously support its recognition as a new member of the alepocephaliform family Platytroctidae. Vachalia moraviensis, gen. et sp. nov., is characterized by a very large head; elongate and ribbon-like body; two premaxillary tusks, of which the posterior is distant from the anterior one and almost perpendicular to it; posterior border of the maxilla behind the orbit; two supramaxillae; nine branchiostegal rays; 22 abdominal and 18 or 19 caudal vertebrae; dorsal fin with 16 or 17 rays; pectoral fin reduced and composed of approximately 12 short rays; pelvic fin larger than pectoral fin; and photophores (apparently) absent. The specimen described herein represents the first and only known fossil belonging to the family Platytroctidae based on articulated skeletal remains.

The world-famous upper Miocene fossil localities on the Aegean island of Samos in Greece have produced a rich fossil record that sheds light on the evolution of eastern Mediterranean terrestrial faunas over a one-million-year interval of the late Neogene. Fossils have been discovered on Samos since antiquity, although a succession of paleontological and commercial collecting expeditions over the last 130 years has resulted in specimens now being distributed throughout museums all over the world. Here, we survey the fossil tortoise remains from Samos, which are significant because they include early antecedents of the modern Testudo lineage, together with spectacular examples of the European Neogene gigantic testudinid †Titanochelon, which represents one of the largest-bodied terrestrial turtle taxa documented to date. All of the Samos fossils derive from the Mytilinii Formation, which spans the late MN11–early MN13 Neogene land mammal zones. The small-bodied tortoise remains include two incomplete shells that are morphologically consistent with basal testudonans and phylogenetically distinct from the coeval species Testudo marmorum found on mainland Greece. The Samos gigantic tortoise †‘Testudo' schafferi was based on a spectacularly large skull and femur. However, we describe new plastron fragments, limb elements, and osteoderms that are compatible with †Titanochelon specimens from southern Greece and Anatolia. This could imply faunal links with the distinctive ‘Pikermian’ local assemblages from Asia Minor and concurs with the proposed late Miocene–Pliocene biogeographic segregation of large mammals from the eastern Aegean margin and Turkey relative to those occurring in northwestern Greece and the Balkan Peninsula.

The Triassic Period (252–201.5 Ma) records a great expansion of saurian diversity and disparity, particularly in skull morphology. Stem archosaurs exhibit substantial cranial disparity, especially by taxa either shortening or elongating the skull. This disparity is exemplified in the North American Late Triassic proterochampsians by the ‘short-faced' Vancleavea and the ‘long-faced' doswelliids. To critically investigate skull elongation and character evolution in these proterochampsians, we evaluate ‘Doswellia’ sixmilensis, known from much of a skull, cervical centra, and osteoderms from the Bluewater Creek Member of the Chinle Formation of New Mexico. We redescribe the holotype based on extensive repreparation of the holotype material, resulting in the identification of the orbit and clarifying the extent of related bones. As such, the diagnosis of the taxon is substantially modified and a new genus, Rugarhynchos, gen. nov., is erected. Rugarhynchos sixmilensis, gen. et comb. nov., exhibits an elongate snout with characteristics known in stem and crown archosaurs, including a downturned premaxilla and fluted teeth. We included R. sixmilensis in a phylogenetic analysis of archosauromorphs consisting of 677 characters and 109 taxa under both parsimony and Bayesian models. We recover R. sixmilensis as a doswelliid, sister to Doswellia kaltenbachi. Our parsimony and Bayesian models differ in the placement of Doswelliidae, either as sister to or within Proterochampsidae, respectively. We use archosauromorph relationships from the Bayesian model to estimate cranial disparity between stem and crown archosaurs and find a narrow breadth of morphological disparity in the stem. Our results suggest that crown archosaurs evolved disparate crania from a low-disparate archosauriform condition.

A monotaxic bonebed containing numerous phytosaur specimens is reported from the Upper Triassic Tiki Formation of India. The comprehensive minimum number of individuals is estimated to be 21, which includes multiple juveniles and subadults, and only a few adults. Such intraspecific aggregation of juvenile-dominated phytosaurs is explained here by parental care and juveniles living in cohorts, as are evident from extant phylogenetic bracketing of either lepidosaurs or crocodiles and birds. The cause of this mass death is probably disease related, after which the carcasses bloated, floated, and disarticulated at the site of death, resulting in an autochthonous assemblage. The carcasses remained submerged under shallow, slow-moving or standing water for a prolonged time and later were subaerially exposed after the recession of water. Subsequently, flooding events resulted in their burial under the overbank fines. Comparison of biostratinomic variables with those of a rhynchosaur-dominated bonebed recovered previously from the same stratigraphic horizon showed distinct differences in their causes of death and fossilization pathways. The latter may be attributed to their habitat differences because the phytosaurs lived in the low-lying areas or ponds and the rhynchosaurs resided on relatively higher and drier areas of the Tiki floodplain.

During the Cretaceous and Paleogene periods, the Earth experienced tectonic and climatic changes, which included continental drift following the breakup of the supercontinents Gondwana and Laurasia, the end-Cretaceous mass extinction event, and several climatic events, including the Paleocene–Eocene Thermal Maximum and the Middle Eocene Climatic Optimum. In response to increased temperatures and vacancies of ecospace left by the extinction of non-avian dinosaurs, mammal and reptile lineages that survived into the Eocene underwent immense evolutionary radiations that led to the diversification of crown clades, such as Crocodylia. Late Eocene deposits in northern Africa provide insights into how crocodyliforms responded to these tectonic and climatic events. Specifically, the Birket Qarun Formation in the Fayum Depression of Egypt contains several species of crown crocodylians as part of its rich fossil record of vertebrates. This study provides description of new material attributable to crocodylian taxa previously known from this formation, as well as newly recognized non-crocodylian mesoeucrocodylian material referable to Sebecosuchia. The sebecosuchian material provides important evidence attesting to the diversity of crocodyliforms in the late Eocene of Africa and expands the known biogeographic range of sebecosuchians.

A dozen non-sauropodan sauropodomorph genera are currently known from southern Africa. The vast majority of the specimens were unearthed in South Africa, but a few were found in Lesotho. We provide here the first complete anatomical description of a historical specimen from Lesotho: ‘the Maphutseng dinosaur.’ The first remains of this animal were uncovered in 1955 and cited in a scientific publication in 1956. Since then, the Maphutseng assemblage has been mentioned in several papers and named on two occasions but never formally published. The bone bed has delivered a huge amount of material from all the regions of the skeleton, of which a small part is described herein. Based on these skeletal elements, and given the unique anatomy of this early sauropodomorph, the new species Kholumolumo ellenbergerorum, gen. et sp. nov., is erected. The remains come from a large number of individuals, making the species the most complete to date from the lower Elliot Formation. Considering all of the material from the Upper Triassic of Gondwana, it is also one of the longest genera known, with adults estimated at up to 9 m long. Despite the large size of the new taxon, it is clearly bipedal and nested deeply among other non-sauropodan sauropodomorphs, suggesting that it is not linked to the origin of Sauropoda.

Although the deep galleries of natural underground cavities are difficult to access and are sometimes dangerous, they have the potential to preserve trace fossils. Here, we report on the first occurrence of sauropod dinosaur tracks inside a karstic cave. Three trackways are preserved on the roof of the Castelbouc cave 500 m under the surface of the Causse Méjean plateau, southern France. The tracks are Bathonian in age (ca. 168–166 Ma), a crucial but still poorly known time interval in sauropod evolution. The three trackways yield sauropod tracks that are up to 1.25 m long and are therefore amongst the largest known dinosaur footprints worldwide. The trackmakers are hypothesized to be titanosauriforms. Some of the tracks are extremely well preserved and show impressions of digits, digital pads, and claws. We erect the new ichnogenus and ichnospecies Occitanopodus gandi, igen. et isp. nov. In order to characterize depositional environments, we conducted sedimentological, petrographic, and mineralogical analyses. The tracks from Castelbouc attest the presence of sauropods in proximal littoral environments during the Middle Jurassic. This discovery demonstrates the great potential of prospecting in deep karst caves that can occasionally offer larger and better-preserved surfaces than outdoor outcrops.

With abundant well-preserved clutches and several adult-clutch associations, oviraptorids provide some of the most detailed information on reproduction for dinosaurs. Here, we describe an oviraptorosaur closely associated with two eggs from the Upper Cretaceous Nanxiong Formation of Jiangxi Province, China, and discuss its implications for various reproductive hypotheses. The specimen consists of a partial skeleton (gastralia, pelvis, portions of both hind limbs, and tail), with one egg within the pelvic canal and the other just posterior to it, ventral to the anterior caudal vertebrae. Several geopetal features indicate that the individual came to rest on its left side, with the eggs likely extruded during buildup of abdominal gases during decomposition. Similarity of pubis, caudal vertebrae, and pes dimensions to recently described material from the formation, e.g., Tongtianlong and Jiangxisaurus, suggests oviraptorid affinities. The specimen provides additional association of elongatoolithid eggs and the oogenus Macroolithus with oviraptorosaurs and further evidence for monoautochronic ovulation, i.e., iterative laying of two eggs at daily or greater intervals. With each egg 36–48% the size predicted for a modern bird of the same adult mass, total egg production would be slightly lower to similar between this non-avian maniraptoran and Neornithes. Histological tissues and open neurocentral sutures indicate that this reproductively active individual was several years old but still growing at the time of death, a pattern observed in other non-avian maniraptorans. The complete absence of medullary bone in this egg-bearing individual may challenge the identification of this tissue in other dinosaurs more distantly related to birds.

Chiniquodontidae is a family of Triassic carnivorous cynodonts well represented in the Middle–Upper Triassic of Argentina and Brazil and, more recently, discovered in Madagascar and central Namibia. The Namibian specimen was found in the uppermost levels of the upper Omingonde Formation and is represented by the skull and partial skeleton. In this contribution, we provide a diagnosis for Chiniquodon omaruruensis, sp. nov., describe the postcranial material, and compare it with that of South American Chiniquodon specimens. Chiniquodon omaruruensis provides the first evidence of elements from the pes in Chiniquodon, and one of the few for non-mammaliaform cynodonts. Chiniquodon omaruruensis has a remarkably large calcaneus with an incipiently differentiated tuber, metatarsal II lateromedially robust but remarkably shorter than metatarsal IV, and an almost quadrangular basal phalanx in digit III. Similar to other Chiniquodon species, it lacks costal plates on ribs and shows a tall and slender scapular blade, a large acromion process positioned well above the scapular neck, and the absence of disc-like phalanges in the autopodium.

Noninvasive computed tomography (CT) scanning techniques performed on the high-quality preserved holotypes of Mendozahippus fierensis (grouped within the paraphyletic ‘Notohippidae') and Gualta cuyana (Leontiniidae) allowed a thorough description of both endocasts, not only associated with the brain but also with closely related endocranial spaces, which proved to be highly diagnostic among Notoungulata and relevant from a paleobiological perspective. The specimens come from Quebrada Fiera (Mendoza, Argentina), an upper Oligocene locality extensively studied, especially during the last decade. Regarding brain endocast proportions and neocortical complexity, M. fierensis shows morphological affinities to coeval ‘notohippids,' whereas G. cuyana resembles Leontinia gaudryi. An acute olfaction is inferred from the large olfactory bulbs and piriform lobes. Conversely, evidence concerning the development (and implications) of some necortical areas (i.e., somatosensory cortex and auditory cortex) were inconclusive. The encephalization quotients are around those previously reported for ‘notohippids’ and Toxodontidae Nesodontinae, and slightly lower than in Typotheria (except for Mesotheriidae). Other endocranial traits previously unexplored (such as the transverse diploic communication between the temporal sinuses in M. fierensis and the large temporal sinuses inferred for G. cuyana) show that there is relevant variability within Toxodontia that deserves further research. Extending similar approaches to early diverging taxa will certainly contribute to a better understanding of the morphological evolution of the brain, special sense organs, and associated blood circulation pattern in toxodontians and notoungulates in general.

Relatively large new samples of the rare plesiadapid mammal Chiromyoides are reported from upper Paleocene rocks exposed along the eastern flank of the Rock Springs Uplift and the adjacent Washakie Basin in southwestern Wyoming. These specimens form the basis for the new upper Tiffanian species Chiromyoides kesiwah and enhance our knowledge of the anatomy of early Clarkforkian C. gingerichi. Multiple previously unreported or unrecognized specimens of Chiromyoides are also described from upper Paleocene faunas in Texas, Colorado, and Wyoming, enabling a new phylogenetic analysis of all known species of Chiromyoides and selected other plesiadapids and outgroup taxa. The phylogeny of Chiromyoides appears to have been more complicated than previously described, partly because the genus was more speciose than previously appreciated. European C. campanicus and C. mauberti are sister taxa that are deeply nested within an otherwise North American radiation of Chiromyoides, suggesting that Chiromyoides originated in North America before dispersing to Europe in the latter part of the Tiffanian. Most of the derived anatomical features that distinguish Chiromyoides from closely related plesiadapids indicate that it was yet another occupant of the lucrative ‘mammalian woodpecker’ niche, alongside the extant Malagasy lemur Daubentonia, the extant phalangeroid marsupial Dactylopsila, early Cenozoic placental Apatemyidae, and possibly the middle Cenozoic metatherian Yalkaparidon.

Two new genera and species of small basal ruminants are described from the middle Eocene Pondaung Formation in Myanmar. One form, Paukkaungmeryx minutus, gen. et sp. nov., is attributed to a primitive Archaeomerycidae, and the other, Stenomeryx bahinensis, gen. et sp. nov., very likely represents the oldest known Tragulidae, a family unknown in Pondaung so far. The fossil record of primitive ruminants in Pondaung is now represented by five genera, and the occurrence of both of these taxa in the Paleogene of Myanmar supports the hypothesis that the initial radiation and diversification of basal ruminants probably occurred during the first part of the Eocene in southern Asia. These discoveries also demonstrate that the fossiliferous sediments of the Pondaung Formation continue to yield new vertebrate taxa that help documenting the evolutionary history of several groups of small mammals.

A turnover of the pinniped fauna took place in the Southern Hemisphere during the Pliocene, based on evidence from South America and South Africa. This resulted in the extinction of early phocids, which were replaced by otariids dispersing from the North Pacific. There is currently a lack of evidence of a similar event from Australia, with the only confirmed phocids from the Miocene–Pliocene boundary and the earliest confirmed otariids from the late Pleistocene. Here, we report a fossil monachine tooth from the Pliocene Whalers Bluff Formation of Portland (Victoria). The tooth represents an extinct monachine seal; it does not resemble either crown lobodontins or miroungins. This is the geologically youngest pre-Holocene occurrence of Phocidae in Australia, and one of the youngest pre-Pleistocene records of phocids in the Southern Hemisphere. It extends the maximum known geochronological range of monachines in the fossil record of Australia to between 6.2 and 2.67 Ma. It is possible that pinniped faunal turnovers in the Southern Hemisphere all occurred during the late Pliocene, with the turnover in Australia occurring sometime after 4.31 Ma. The description of additional Australasian fossil pinnipeds will further constrain this faunal turnover event.

The modern pygmy and dwarf sperm whales (Physeteroidea, Kogiidae) are remnants of a highly diverse group, which flourished in the Miocene oceans. Unlike their modern suction-feeding, deep-diving relatives, the past diversity of this family includes animals with disparate ecological habits. Here, we describe Scaphokogia totajpe, sp. nov., a new species of kogiid based on a well-preserved skull from the upper Miocene strata of the Pisco Formation, Peru. A phylogenetic analysis places S. totajpe as sister taxon of S. cochlearis and divides Kogiidae into two clades: the first including both species of Scaphokogia and the second including Kogia, Koristocetus, Praekogia, and Nanokogia. Similar to S. cochlearis, S. totajpe has a tubular rostrum with a hypertrophied mesorostral canal, a large supracranial basin, and a leftward deviated facial sagittal crest, but it differs by possessing a proportionately shorter rostrum, a reduced projection of the lacrimojugal between the frontal and the maxilla, and a flat occipital shield. The cranial morphology of Scaphokogia indicates that the extent of the nasal complex was greater than in modern kogiids. Furthermore, the overall rostrum shape and the reconstructed muscle insertion sites indicate that Scaphokogia retained some plesiomorphic features related to a more generalist ecology. Inclusion of S. totajpe into the context of the Pisco Formation indicates that during the late Miocene, the Peruvian coastal system was a hot spot for the diversification of physeteroids, with at least four species coexisting. Finally, Scaphokogia totajpe highlights a late Miocene diversity peak for sperm whales in the global oceans, before the Pliocene odontocete turnover.