Bioinspiration is an approach to innovation based on the observation of biological systems, of which only 0.1% remain since life began 3.7 billion years ago. Expanding the scope of bioinspiration to the fossil record greatly increases the diversity of potential biological "muses" and provides a means to understand the form, function and origins of current living systems. This extended approach, here termed "palaeo-bioinspiration", has already been applied to the fields of hydrodynamics, aeromechanics, actuators, protective technology and building construction. To reach its full potential, palaeo-bioinspiration has to overcome the misconception that fossils are "failures" or "primitive", and temper the widespread belief that extant biodiversity is inherently "optimised". By encouraging interdisciplinarity, investing in technical infrastructure and collaborating with both Natural Science institutions and industry, palaeo-bioinspiration could become a powerful asset within the bioinspiration domain.

Here we describe a new specimen of Archaeopteryx sp. from the lower Tithonian Mörnsheim Formation in the Franconian Alb of Bavaria, Germany. This fossil is the third avialan specimen found in this formation. The skeleton comprises the right forelimb and shoulder as well as fragments of the left forelimb and both hind limbs. The lengths of the humerus and ulna are most similar to those of the Munich specimen of Archaeopteryx. Despite the specimen having been massively altered by late diagenesis, it can be referred to Archaeopteryx sp., based on the morphology of the furcula, coracoid, humerus and radius, as well as a manual ungual, which nests within the morphospace of Archaeopteryx rather than that of Anchiornis. Phylogenetic analyses also support the assignment of the new specimen to Archaeopteryx. Due to the fossil’s state of preservation, as well as the still-unresolved taxonomy of the genus Archaeopteryx on the species level, an identification beyond genus remains impossible.

The Late Permian Weigeltisauridae are the world's first gliding reptiles, but much remains unknown regarding the anatomy of their patagium (or wing), which, in turn, confounds our understanding of their gliding mechanism and paleobiology. Here, we examine the morphology and osteo-histology of the patagial skeleton of weigeltisaurids using an array of imaging techniques and several thin sections through the wing skeleton of a specimen of Weigeltisaurus from the Late Permian of Germany. We demonstrate that patagials and gastralia share a one-to-one articulation, permitted by the uniquely specialized anatomy of the lateral gastralia. We also show, based on skeletal anatomy, histology, and inferred musculoskeletal relationships, that patagials are likely neomorphic ossifications and are thus not strictly homologous to the gastralia. We provide the first reconstruction of the musculoskeletal anatomy of the weigeltisaurid wing, suggesting that the base of the patagials was likely embedded in the M. obliquus externus group. Similar to the condition in the extant flying lizard Draco, these muscles may have contributed to the unfolding of the patagium, which was likely supported by hooking the manual claws onto the leading edge of the patagium. This would have provided weigeltisaurids with a means to maintain the patagium expanded and under tension while gliding, as well as some measure of control of the dihedral angle of the wing, thereby offering a means to control stability and maneuverability in flight. Wing folding may have been permitted by muscular and tendinous connections between the elements of the patagial skeleton, generating elastic tension toward a folded state, as in Draco. Lastly, the cross sections of the patagials show a bimodal cortical distribution with much thicker cortices along their cross-sectional long axis than short axis. This made the patagials rigid, which likely helped prevent patagial collapse during gliding. This work represents a critical step toward understanding the wing structure and gliding mechanism in weigeltisaurids, paving the way for future morphofunctional or biomechanical studies on the locomotion of the world's first flying vertebrates.

The anatomy of Late Triassic drepanosauromorphs is re-examined, with a focus on the previously published surface models of the holotype of Avicranium renestoi from the Norian of North America. We comment on the cranial anatomy of this taxon and propose a new reconstruction of the skull and mandible. Contrary to previous interpretations, the entire rostrum and most of the palate are not preserved in this specimen. We also suggest that some proposed plesiomorphic characters may result from incomplete ossification due to immaturity. These new observations are compiled into a new morphological phylogenetic dataset designed to address the monophyly of 'Avicephala', the group comprising the Late Permian gliding reptiles Weigeltisauridae, and the Late Triassic chameleon-like Drepanosauromorpha. We recover Weigeltisauridae as stem-saurian diapsids and Drepanosauromorpha as sister-group to Trilophosauridae among archosauromorphs, thus implying the paraphyly of 'Avicephala'. Drepanosauromorphs and trilophosaurids are recovered as sister-taxa for the first time, as supported by several cranial and postcranial synapomorphies. This new phylogenetic position of Drepanosauromorpha reduces the group's ghost lineage that now does not necessarily cross the Permian-Triassic boundary. However, much remains unknown of the early history of trilophosaurids and drepanosauromorphs, and of the evolution of arboreality in Triassic archosauromorph reptiles.

Early Cretaceous ichthyosaurs were globally distributed pelagic marine reptiles, but many remains are fragmentary, creating a Northern Hemisphere diversity bias. A rich Hauterivian locality near the Tyndall Glacier inside Torres del Paine National Park in southern Chile yields important new data regarding ichthyosaurian diversity along the Pacific margin of Gondwana. These new data will contribute to clarifying questions regarding ichthyosaur taxonomy and the palaeobiogeographical relationships between the southern Gondwanan and Northern Hemisphere ichthyosaur groups during the Early Cretaceous. Here, we describe three new ichthyosaur specimens from this locality. Two of them are referred to Myobradypterygius hauthali, expanding the distribution of this species from the Barremian of Argentina to the Hauterivian of the Chilean Patagonia. This material shows that M. hauthali differs from Platypterygius platydactylus in forefin construction and scapular morphology, supporting its classification as a separate genus within Platypterygiinae. The third specimen is a large-bodied indeterminate ophthalmosaurine ichthyosaur. This record represents the southernmost record of Ophthalmosaurinae and the first occurrence of this group from the Cretaceous of the Southern Hemisphere. These discoveries show that ophthalmosaurines and platypterygiines continued to occur sympatrically in southernmost Gondwana during the Early Cretaceous, expanding the pattern documented in Europe to the Pacific region.

The fossil fishPtychodusAgassiz, 1834, characterized by a highly distinctive grinding dentition and an estimated gigantic body size (up to around 10 m), has remained one of the most enigmatic extinct elasmobranchs (i.e. sharks, skates and rays) for nearly two centuries. This widespread Cretaceous taxon is common in Albian to Campanian deposits from almost all continents. However, specimens mostly consist of isolated teeth or more or less complete dentitions, whereas cranial and post-cranial skeletal elements are very rare. Here we describe newly discovered material from the early Late Cretaceous of Mexico, including complete articulated specimens with preserved body outline, which reveals crucial information on the anatomy and systematic position ofPtychodus. Our phylogenetic and ecomorphological analyses indicate that ptychodontids were high-speed (tachypelagic) durophagous lamniforms (mackerel sharks), which occupied a specialized predatory niche previously unknown in fossil and extant elasmobranchs. Our results support the view that lamniforms were ecomorphologically highly diverse and represented the dominant group of sharks in Cretaceous marine ecosystems.Ptychodusmay have fed predominantly on nektonic hard-shelled prey items such as ammonites and sea turtles rather than on benthic invertebrates, and its extinction during the Campanian, well before the end-Cretaceous crisis, might have been related to competition with emerging blunt-toothed globidensine and prognathodontine mosasaurs.

Direct evidence of trophic interactions between extinct species is rarely available in the fossil record. Here, we describe fish-mammal associations from the middle Eocene of Messel (Germany), consisting of three specimens of holosteans (one Atractosteus messelensis (Lepisosteidae) and two Cyclurus kehreri (Amiidae)) each preserved with a bat specimen (Palaeochiropteryx tupaiodon) lying in close contact with its jaws. This suggests that these fishes probably died after failed swallowing attempts, with the bat wing membrane entangled in their jaws resulting in a fatal handicap. Based on data from modern gars and bowfins, A. messelensis and C. kehreri may have opportunistically attacked drowning and dying individuals or scavenged on floating/sinking carcasses. This hypothesis is also supported by the unusually high number of bat specimens preserved in the deposits of the Eocene Lake Messel, suggesting that this group of small mammals may have represented a substantial food source for generalist feeders. This is the earliest case of chiropterophagy and the first known evidence of bat consumption by lepisosteid and amiid fishes, emphasizing the high trophic variability and adaptability of these groups throughout their evolutionary histories. The newly described associations provide important information for reconstructing the Eocene Lake Messel palaeoecosystem and its trophic web.

Chelydropsis is a genus of the clade Pan-Chelydridae, which existed and was distributed in Eurasia from the Eocene to the end of the Pliocene. The Chelydropsis fossil record of North of the Alps is particularly rich throughout the Miocene. In this study, we describe a new Chelydropsis species from the Late Miocene (Vallesian, MN9) fossiliferous site of H & ouml;wenegg in southwestern Germany. The new species is based on a nearly complete Chelydropsis skeleton, which stands out among the best preserved and most complete specimens ever found until now. The new species, Chelydropsis heweneggensis sp. nov. is of particular importance. It differs from the coeval Chelydropsis murchisoni, which recent studies suggest is the only Chelydropsis species known to have existed in Europe from the Middle Miocene to the Pliocene. The species described herein thus adds to the diversity of the European Neogene Chelydropsis record.

A new long-legged, spatula-beaked, filter-feeding pterodactyloid pterosaur from Upper Jurassic plattenkalk limestones at Wattendorf, Bavaria, Southern Germany, is remarkable for its completeness, unusual dentition and hints of the preservation of soft tissues, including wing membranes. The fully articulated specimen displays both jaws each side with over one hundred sub-parallel-sided teeth with a small, slightly hooked expansion at the crown tip. There are at least 480 teeth in total. The tip of the rostrum widens to a spatula-like, laterally concave structure with teeth only along its lateral margins. The straight anterior margin is devoid of teeth allowing plankton-rich water to stream in, while the teeth interdigitate forming a fine mesh trap. A slightly up swept rostrum assisted filtering by probable pulsating movements of the long neck, while wading or swimming through shallow water.

In the dusk of the Mesozoic, advanced duck-billed dinosaurs (Hadrosauridae) were so successful that they likely outcompeted other herbivores, contributing to declines in dinosaur diversity. From Laurasia, hadrosaurids dispersed widely, colonizing Africa, South America, and, allegedly, Antarctica. Here, we present the first species of a duck-billed dinosaur from a subantarctic region, Gonkoken nanoi, of early Maastrichtian age in Magallanes, Chile. Unlike duckbills further north in Patagonia, Gonkoken descends from North American forms diverging shortly before the origin of Hadrosauridae. However, at the time, non-hadrosaurids in North America had become replaced by hadrosaurids. We propose that the ancestors of Gonkoken arrived earlier in South America and reached further south, into regions where hadrosaurids never arrived: All alleged subantarctic and Antarctic remains of hadrosaurids could belong to non-hadrosaurid duckbills like Gonkoken. Dinosaur faunas of the world underwent qualitatively different changes before the Cretaceous-Paleogene asteroid impact, which should be considered when discussing their possible vulnerability.

Files 1-3: RTI interactive photographs of the skulls of the drepanosauromorphs Megalancosaurus preonensis Calzavara, Muscio and Wild, 1980 and Vallesaurus cenensis Renesto and Binelli, 2006 (Norian, Italy). Reflectance Transformation Imaging (RTI) is a method that computes an 'interactive specimen' on which the illumination can be oriented at will. Sets of 54 photographs under different LED sources were compiled using the RTIBuilder software. The RTI files can be opened using the RTI vewer software (both softwares are freely available at www.culturalheritageimaging.org). Files 4-6: Nexus files of phylogenetic taxon-character matrices and backbone constraints used in phylogenetic analyses. Currently only available upon request for reviewers, but will be made public after acceptance of article for publication.

An incomplete fossil record and unstable phylogenies of extinct taxa hamper reconstructing the early evolution of Caimaninae. We describe previously unpublished articulated fossils of a key species, Tsoabichi greenriverensis from the early Eocene Green River Formation of North America, exhibiting further character evidence for the caimanine affinities of this taxon. Parsimony analysis of modified morphological taxon-character datasets coupled with a critical review of character evolution and published phylogenies reveals that fossil evidence for Palaeogene crown group and Late Cretaceous total-group representatives is unreliable due to uncertain character evolution in early Alligatoridae. The earliest unambiguous fossil age for total and crown-group Caimaninae are 63.5 Ma and 18.06 Ma, respectively. These calibration points follow best practices and are vital for better constrained estimates of time calibrated analyses. Phylogeny continues to imply two separate Caimaninae dispersals between North and South America, but instead of a northward back-dispersal, we find two Palaeogene dispersals to South America an equally likely hypothesis. Miocene taxa of Central America previously assigned to the stem lineage ancestral to South American Caimaninae are reinterpreted as part of a Neogene northward expansion of the crown group.

In contrast to other kinds of biological interactions, symbiosis is a scarcely investigated aspect of the fossil record. This is largely due to taphonomic biases that often frustrate any attempt to make a strong case that two organisms shared an intimate association in life. Among extant marine vertebrates, the sea turtles (Cheloniidae and Dermochelyidae) bear a broad and diverse spectrum of epibiotic symbionts, including specialists such as the turtle barnacles (Chelonibiidae and Platyleapadidae). Here, we reappraise an early Oligocene (Rupelian) fossil cheloniid skeleton, featuring the remains of cirripedes on the exterior of its entoplastron, from the Rauenberg fossil-lagerstätte , southwestern Germany. The barnacle specimens are assigned to Protochelonibia melleni , an extinct protochelonibiine species and the geologically oldest known member of Chelonibiidae. In the light of taphonomic and palaeoenvironmental considerations, and given that the extant chelonibiids are mostly known as epizoic symbionts of sea turtles, we conclude that this unique fossil association resulted from the epizoic growth of the barnacles on the external surface of the plastron of the turtle during its lifetime. This remarkable fossil association provides evidence that chelonibiids, including the extinct protochelonibiines, have been chelonophilic epizoans for more than 30 Myr. A survey of the trace and body fossil records shows that platylepadids are also likely as old as the Rupelian as is their symbiotic association with cheloniid hosts. This early emergence of the modern-looking, turtle-dwelling barnacle lineages corresponds to a climate-driven phase of major radiation and taxonomic turnover among sea turtles at the Eocene–Oligocene transition.

The postcranial skeleton of the gliding neodiapsid reptile Coelurosauravus elivensis (Lower Sakamena Formation, ?upper Permian, southwestern Madagascar) is re-described in detail based on all previously referred specimens. The exquisite preservation of the material provides three-dimensional details of the individual bones, which are missing in the Laurasian weigeltisaurid material. A new skeletal reconstruction of C. elivensis is proposed including the first reconstruction of a weigeltisaurid reptile in lateral view. The re-examination of the material highlights interspecific differences in the postcranium of weigeltisaurids, in particular in the trunk and patagial spars. These animals have long been considered as arboreal and gliding reptiles. However, new information on the postcranium of C. elivensis reveals strong similarities with both extant and extinct quadrupeds specialized for a clinging arboreal lifestyle. Additionally, the presence of an additional phalanx in the fifth digit of the manus is now attested for all weigeltisaurids where this region is preserved. We suggest that this morphology could have allowed weigeltisaurids to grasp their patagium as observed in the extant gliding agamid Draco. Weigeltisaurids are thus the earliest known gliding vertebrates and some of the first tetrapods with an obligatory arboreal lifestyle, but also represent the only known vertebrates with a hyperphalangy aligned with a gliding apparatus.

Recent palaeontological research in submerged caves of the north-eastern Yucatan Peninsula (YP) in Mexico has resulted in the identification of a diverse megafaunal assemblage in the area, among them Late Pleistocene ground sloths assigned to the family Megalonychidae (Xenarthra). Here we report on a new species of Megalonychidae,Xibalbaonyx exinferisn. sp., from a new fossil locality named cenote Tortugas, located west of Puerto Morelos in the federal state of Quintana Roo. The taxon is based on a fragmentary left mandibular ramus, an atlas, and a left humerus. The new taxon is diagnosed by the presence of two mental foramina on the short symphyseal spout, a caniniform being the smallest mandibular tooth, and the anterolaterally directed aperture of the mandibular foramen on the lateral surface of the mandible.Xibalbaonyx exinferisis the third endemic megalonychid documented for the north-eastern Yucatan Peninsula and thus provides increasing evidence for an ecological isolation of the area from the rest of Mexico during the Pleistocene.

Schubert and colleagues have recently criticized our assessment of the mandibular ramus of a small peccary from Muknal cave in Quintana Roo, Mexico, to a new genus and species, 'Muknalia minima' Stinnesbeck et al. 2017. They considered this assignation as invalid and the unique morphologies of the taxon to be the result of breakage and human modification. We strongly disagree with this interpretation and maintain our original view of a new genus and species.

Ongoing investigations in submerged cave systems of Quintana Roo in south-eastern Mexico reveal a rich Late Pleistocene megafaunal assemblage, among them the megalonychid ground slothXibalbaonyx oviceps. The taxon has been described based on a complete skull and mandible from El Zapote cenote west of Puerto Morelos. We here add hitherto unreported postcranial material from El Zapote, attributed to the holotype. This new material allows us to reconstruct unexpected locomotion capabilities forXibalbaonyx ovicepsincluding steep slope and rock climbing. This may have enabled the ground sloth to use the sinkholes and underground caverns as water resource and shelter. The Late Pleistocene age of the fossil allows for a co-existence with early human settlers on the Yucatan Peninsula.

The cranial skeleton of the enigmatic gliding neodiapsid reptile Coelurosauravus elivensis (Lower Sakamena Formation, Lopingian, Southwestern Madagascar) is re-described in detail. All previously referred specimens are re-examined under both direct observations and Reflectance Transformation Imaging. Their exquisite preservation yields detailed three-dimensional information on the outline of individual bones and their osteological relationships, which are missing in the Laurasian remains. In contrast to previous studies, the ontogenetic maturity of all specimens is re-affirmed. Previously unidentified elements of the palate, braincase and mandible are described, and a novel reconstruction is proposed, including the first palatal reconstruction in a weigeltisaurid reptile. C. elivensis has the smallest skull of all weigeltisaurids and differs from other species in its facial ornamentation, parietosquamosal frill and larger anterior maxillary dentition. We also provide extensive comparisons with contemporaneous reptiles, possibly closely related taxa and more recent analogs, as well as a preliminary discussion of the functional anatomy of the peculiar cranial morphology of weigeltisaurids. The cranial skeleton is a truss construction with large orbits and temporal fenestrae. By analogy with extant chamaeleonids, the elongate parietosquamosal frill is associated with an increase in length and diameter of the temporal jaw adductors, resulting in an increased gape and/or bite force and speed. Additionally, the spikes and frills of weigeltisaurids most likely served as a display and defensive structure.