Search

Pterosaurs, the first true flying vertebrates, played a crucial role in Mesozoic terrestrial ecosystems. However, our understanding of their ability to move around on the ground and, more broadly, their terrestrial paleoecology remains limited. Here, we demonstrate an unexpectedly high degree of variation in the hands and feet of pterosaurs, comparable with that observed in extant birds. This suggests that pterosaurs were adapted to a remarkably broad range of non-aerial locomotor ecologies. Small, early, long-tailed pterosaurs (non-pterodactyliforms) exhibit extreme modifications in their hand and foot proportions indicative of climbing lifestyles. By contrast, the hands and feet of later, short-tailed pterosaurs (pterodactyliforms) typically exhibit morphologies consistent with more ground-based locomotor ecologies. These changes in proportions correlate with other modifications to pterosaur anatomy, critically, the separation along the midline of the flight membrane (cruropatagium) that linked the hindlimbs, enabling a much more effective locomotory ability on the ground. Together, these changes map a significant event in tetrapod evolution: a mid-Mesozoic colonization of terrestrial environments by short-tailed pterosaurs. This transition to predominantly ground-based locomotor ecologies did not occur as a single event coinciding with the origin of short-tailed forms but evolved independently within each of the four principal radiations: euctenochasmatians, ornithocheiroids, dsungaripteroids, and azhdarchoids. Invasion of terrestrial environments by pterosaurs facilitated the evolution of a wide range of novel feeding ecologies, while the freedom from limitations imposed by climbing permitted an increase in body size, ultimately enabling the evolution of gigantism in multiple lineages. • The hands and feet of pterosaurs were adapted to a broad range of locomotor ecologies • Early pterosaurs had a scansorial mode of life, which restricted maximum body size • Anatomical changes in later pterosaurs led to more effective terrestrial ability • Invasion of terrestrial habitats facilitated diverse feeding ecologies and gigantism Smyth et al. show that pterosaurs exhibit significant disparity in their hand and foot morphologies. This indicates that they occupied a broad range of locomotor ecologies. Early pterosaurs were adapted for climbing, while later forms evolved more effective terrestrial locomotion, which facilitated diversification and the evolution of gigantism. [ABSTRACT FROM AUTHOR]

From the first animals crawling on the sea floor to pterosaurs rising to the sky with wingspans up to ten metres across, understanding animal moves of the deep evolutionary past remains a challenge. In addition to exceptional fossils, advanced computer modelling methods and soft robotics are now helping to elucidate how bygone species were able to walk, swim and fly. Michael Gross reports. From the first animals crawling on the sea floor to pterosaurs rising to the sky, understanding animal moves of the deep evolutionary past remains a challenge. In addition to exceptional fossils, advanced computer modelling methods and soft robotics are now helping to elucidate how bygone species were able to walk, swim and fly. [ABSTRACT FROM AUTHOR]

An incomplete right metacarpal IV of a pterosaur from the late Albian Paw Paw Formation of Texas, USA, is the second pterosaur from that formation and an important addition to the sparse pterosaur record of the Albian of North America. Although the proximal and distal ends are missing, what remains of the shaft is straight and slender with little taper, little anteroposterior compression, and a distinct distal neck, and indicates the individual was of modest size despite being fully mature, and on that basis the specimen is referred to the Tapejarinae and is the first record of that taxon in North America. The specimen exhibits numerous bite marks of various types that are interpreted as resulting from intense scavenging by at least two different shark species and perhaps a bony fish. [ABSTRACT FROM AUTHOR]

It can be arduous to discriminate between lamellar bone fibres, Sharpey's fibres (tendon insertions) and the pneumosteum (air sac diverticula interaction with the bone) during histological observations. We analysed thin sections of several avemetatarsalians from the Cretaceous of Brazil and used characters from optical mineralogy to differentiate these biomineralized tissue types, resulting in a solid criterion for histological comparison. The observation scale is one of the best guides to differentiate the tissues. Lamellar bone fibres are only perceptible at very high magnifications (100×) whereas Sharpey's fibres are detectable at low magnification (5×). Pneumosteal bone fibres are discernible at 40–50×. Hence, fibre length is longer in Sharpey's fibres than in the pneumosteum. High optical relief is a good proxy to detect connective tissue insertion scars (Sharpey's fibres). Finally, texture is an excellent proxy to identify pneumosteal bone. The asbestiform aspect of this structure is so far unique among several bone tissue types. [ABSTRACT FROM AUTHOR]

The hindlimb of pterosaurs has been much less studied than the pterosaur wing. However, it is relevant to understand the evolution, phylogeny and ecology of these animals. This study provides the first complete and detailed description of the ankle of Pterodaustro guinazui. It documents three ontogenetic stages observed for the fusion of the tibiotarsus: in the youngest specimens the proximal tarsals are not fused to the tibia; in the subadults the tibiotarsus is formed, but with the suture still visible; in the adults, the tibiotarsus is entirely formed, without any suture. The fusion between astragalus and calcaneum precedes tibiotarsal fusion, but in close succession. The medial condyle of the tibiotarsus is made up of the astragalus, and the lateral condyle is composed of the calcaneum and part of the astragalus. The distal tibiotarsus has three articular facets, the most medial of which seems to greatly restrict the flexion-extension movement, a feature atypical of pterosaurs. The lateral part of the distal tibiotarsus, on the contrary, allows a very wide range of movement. Pterodaustro guinazui seems to have had an asymmetrical ankle joint, which could facilitate movements linked to wading behavior. We describe juvenile specimens that retain discrete distal tarsals Ⅱ and Ⅲ (common in the “non-pterodactyloid” pterosaurs), but also more mature specimens with completely fused distal tarsals Ⅱ and Ⅲ (a condition always observed in the late pterodactyloids). Moreover, the lateral distal tarsal (LDT) appears more robust in Pterodaustro than in Peteinosaurus or Dimorphodon, but shares a waisted shape with these taxa, unlike the more robust shape of the LDT of late pterodacty-loids. The new information on the Pterodaustro ankle improves our anatomical knowledge of the basal Pterodactyloidea.

The Istiodactylidae is one of three ornithocheiroid pterosaur lineages, characterised by a large nasoantorbital fenestrae and labiolingually compressed teeth. Their remains have been reported from Early Cretaceous rocks of northeastern China and Western Europe. A new istiodactylid pterosaur from the upper part of the Yixian Formation (Jingangshan Member) of the Jehol Group, distributed in western Liaoning Province and neighbouring areas, is described on the basis of an incomplete specimen including the partial skull, forelimb and hindlimb bones, and pelvis. This individual, here designated as a referred specimen of Nurhachius (Nurhachius sp.) is a skeletally almost mature pterosaur with an estimated wingspan of 1.6 m. This specimen is not only the geologically oldest known occurrence of Nurhachius, but also a new component of the pterosaur assemblage of the Jingangshan Member, and provides new information on the pelvis and hindlimb of istiodactylids and the palaeobiology of this clade. Considering previous reports of the istiodactylid remains and the geological ages of the strata that yielded them, it is suggested that different istiodactylids existed in Europe and China during the late Barremian. [ABSTRACT FROM AUTHOR]

Take-off is a vital part of powered flight which likely constrains the size of birds, yet extinct pterosaurs are known to have reached far larger sizes. Three different hypothesised take-off motions (bipedal burst launching, bipedal countermotion launching, and quadrupedal launching) have been proposed as explanations for how pterosaurs became airborne and circumvented this proposed morphological limit. We have constructed a computational musculoskeletal model of a 5 m wingspan ornithocheiraean pterosaur, reconstructing thirty-four key muscles to estimate the muscle moment arms throughout the three hypothesised take-off motions. Range of motion constrained hypothetical kinematic sequences for bipedal and quadrupedal take-off motions were modelled after extant flying vertebrates. Across our simulations we did not find higher hindlimb moment arms for bipedal take-off motions or noticeably higher forelimb moment arms in the forelimb for quadrupedal take-off motions. Despite this, in all our models we found the muscles utilised in the quadrupedal take-off have the largest total launch applicable moment arms throughout the entire take-off sequences and for the take-off pose. This indicates the potential availability of higher leverage for a quadrupedal take-off than hypothesised bipedal motions in pterosaurs pending further examination of muscle forces. [ABSTRACT FROM AUTHOR]

Pterosaurs, flying reptiles that lived during the Mesozoic era, were the first vertebrates to develop powered flight. Despite being patchy, the pterosaur fossil record extends worldwide, being quite diverse at the Araripe Basin, Brazil. The Romualdo Formation (Aptian-Albian), a Konservat Lagerstätten rich in calcareous concretions, has yielded several of these exceptionally well-preserved, three-dimensional fossils. MN 4727-V, the focus of the present study, consists exclusively of three-dimensionally preserved post-cranial axial and appendicular elements. The anatomy suggests that MN 4727-V is a pteranodontoid since it exhibits an enlarged, warped deltopectoral crest and a subtriangular distal articulation of the humerus. The phylogenetic analysis recovered MN 4727-V as an anhanguerid by the combination of the following characters: scapula substantially shorter than the coracoid (sca/co < 0.80), and posterior expansion of the sternal articulation of the coracoid. The presence of elliptical-shaped, dorsomedially inclined depressions on the dorsal surface of the prezygapophyses of the preserved cervicals has never been reported for any other anhanguerid, although they might not be diagnostic to MN 4727-V. The tail bears unique middle caudals that exhibit ventral projections, a character previously reported only for Anhanguera piscator. The wingspan of MN 4727-V, a juvenile individual, was estimated to be about 3.9 metres. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that the invasive air sac system evolved at least three times independently in avemetatarsalians: in pterosaurs, sauropodomorphs and theropods. Data from sauropodomorphs showed that the pneumatic architecture in vertebrae first developed in camellate‐like trabeculae in the Triassic, later in camerate systems in Jurassic neosauropods, and finally camellate tissue in Cretaceous titanosaurs. This evolutionary trajectory has support from a considerable sampling of sauropodomorph taxa. However, the evolution of pneumatic bone tissues in Theropoda is less understood. We analyzed the computed tomography of Majungasaurus and Rahonavis, using densitometry rendering to differentiate the microarchitecture along the presacral axial skeleton of late Ceratosaurians and early Paravians. We also compared these results with scans of other theropod clades. Our analysis revealed an increase in pneumatic complexity in early paravians compared to the ceratosaurians. Majungasaurus presents some apneumatic neural spines, a condition also observed in Allosaurus. Majungasaurus also features some apneumatic centra despite the presence of lateral pneumatic fossae. This raises caution when evaluating PSP solely based on external morphology. We also found evidence of distinct patterns of PSP in maniraptorans. Considering that Majungasaurus, a late abelisaurid, inherited from their ceratosaurian ancestors, some apneumatic elements such as the neural spine and some centra, Rahonavis, an early paravian, took a different trajectory toward the full pneumatization of the axial skeleton. This characteristic provided paravians an advantage in gliding and flying. Also, unlike Sauropoda, pneumaticity in Theropoda apparently developed by increasing chamber volumes toward paravians. Similar studies on early Theropoda are needed to elucidate their condition and better describe the evolutionary trajectory of different groups. [ABSTRACT FROM AUTHOR]

Caiuajara dobruskii is a tapejarine pterosaur from a unique pterosaur bonebed in southern Brazil, where hundreds of bones referred to this species have been described. Despite its abundance, specimens were found disarticulated and/or disassociated, hindering ontogenetic interpretations from anatomy. Osteohistology is a proper approach to obtain information on ontogeny as well as other palaeobiological information. Here, we analyse 28 thin sections of distinct appendicular bones, from 18 different specimens belonging to Caiuajara dobruskii. All samples display a fibrolamellar microstructure, which suggests that Caiuajara dobruskii had high metabolic rates throughout its life history. We propose five different histology-based ontogenetic stages: Early juvenile; Late juvenile; Juvenile-to-subadult transition; Subadult; and Adult. When compared with other pterosaur ontogenetic series, Caiuajara had a higher bone deposition ratio than other pterosaurs such as Pterodaustro and Rhamphorhynchus, even when compared with the youngest individuals of those taxa. The fact that this bonebed shows a large accumulation of juvenile specimens in this bonebed, whereby adults are rare and senile are absent, suggest that C. dobruskii might have developed similar to some behaviours present in extant birds, as a breeding point and/or creching. [ABSTRACT FROM AUTHOR]

Herein, we describe the first pterosaur material from the Lower Cretaceous of Victoria and the geologically oldest pterosaur material from Australia. The isolated material comprises a partial synsacrum and a left metacarpal IV from the lower Albian portion of the Eumeralla Formation at Dinosaur Cove, Cape Otway, Victoria. The vestiges of a supraneural plate in the synsacrum precludes assignment to the Azhdarchidae. Moreover, presence of a supraneural plate indicates that the synsacrum likely belongs to individual late in ontogeny, perhaps attaining osteological maturity. The synsacrum does not preserve any diagnostic features, and is regarded here as an indeterminate member of either the Archaeopterodactyloidea or Pteranodontia. Similarly, the metacarpal IV cannot be identified more precisely than Pterosauria indet. Positive identification of the fourth metacarpal is supported by the presence of a ginglymoid distal articular surface and proximodistal length. The metacarpal IV is distinct from others previously reported from Australia, in that it is substantially smaller; it is therefore interpreted to derive from a juvenile specimen. Despite the isolated nature of these remains, they extend the temporal and geographic range of pterosaurs in Australia, and in tandem with remains described elsewhere, indicate that the Pterosauria prevailed and potentially reproduced at high latitudes. [ABSTRACT FROM AUTHOR]

The Caiuá Group (Cretaceous of Southern Brazil) is famous for the Pterosaur Graveyard site, a location that has yielded hundreds of tapejarid specimens, among other taxa. Previous works had already presented various specimens of Pterosaur Graveyard (PG) tapejarids, reporting on several cranial elements showing substantial anatomical variations. These variations have been interpreted as intraspecific in nature, with all tapejarid specimens having been attributed to a single species, Caiuajara dobruskii. The present contribution reassesses the morphological diversity found in PG tapejarid specimens. Evidence is provided for the interpretation of several variations as interspecific in nature, particularly regarding rostral, palatal, occipital, and third cervical morphology. The present data indicate a segregation of the PG tapejarid specimens between two consistent morphotypes, which are interpreted here as two distinct, coexisting species: Caiuajara dobruskii and Torukjara bandeirae gen. et sp. nov. [ABSTRACT FROM AUTHOR]

The fossil remains of a pterodactyloid pterosaur from the Kimmeridge Clay Formation (Jurassic: Tithonian) of Abingdon, Oxfordshire, central England are identified as a partial left first wing finger phalanx. The elongation of the phalanx and distinctive morphology of the proximal articular region, in particular the square outline of the extensor tendon process, permit the specimen to be assigned to Ctenochasmatoidea. Although fragmentary, it is sufficiently well preserved to determine accurately its dimensions when complete. Morphometric analysis reveals the specimen to represent one of the largest known examples of a Jurassic pterosaur, with an estimated wingspan of at least 3 m, and is one of the first pterodactyloids to be reported from the Jurassic of the United Kingdom. [ABSTRACT FROM AUTHOR]

Among the least studied portion of the pterosaur skeleton is the palate, which tends to be poorly preserved and commonly only visible from one side (the ventral portion). Even in well-preserved specimens, the bones tend to be fused, with the limits of individual palatal elements obscured. To shed new light on this region, we employed advanced X-ray imaging techniques on the non-pterodactyloid Kunpengopterus (Wukongopteridae), and the pterodactyloids Dsungaripterus (Dsungaripteridae), Hongshanopterus (Istiodactylidae), and Hamipterus (Hamipteridae). Our analyses revealed the presence of sutures between palatal bones in Dsungaripterus and Kunpengopterus, which resulted in different interpretations of the relation between palatine, ectopterygoid, and pterygoid, leading to a new identification of the palatal openings. Furthermore, our study shows six main observations such as the variation of the angle between the palatine rami and the variation in the relative sizes of the palatal openings. We also point out that the presence of a maxillopalatine fenestra (previously identified as postpalatine fenestra), is unique within Diapsida. Although much more work needs to be done, we showed that advanced X-ray imaging techniques open a window for understanding pterosaur cranial anatomy and provide a new perspective for investigating the evolutionary history of these flying reptiles. A study on the palatal region of pterosaurs suggests different bone interpretations and new identification of the palatal openings, pointing out that the maxillopalatine fenestra in pterosaurs is unique within Diapsida. [ABSTRACT FROM AUTHOR]

The hindlimb of pterosaurs has been much less studied than the pterosaur wing. However, it is relevant to understand the evolution, phylogeny and ecology of these animals. This study provides the first complete and detailed description of the ankle of Pterodaustro guinazui. It documents three ontogenetic stages observed for the fusion of the tibiotarsus: in the youngest specimens the proximal tarsals are not fused to the tibia; in the subadults the tibiotarsus is formed, but with the suture still visible; in the adults, the tibiotarsus is entirely formed, without any suture. The fusion between astragalus and calcaneum precedes tibiotarsal fusion, but in close succession. The medial condyle of the tibiotarsus is made up of the astragalus, and the lateral condyle is composed of the calcaneum and part of the astragalus. The distal tibiotarsus has three articular facets, the most medial of which seems to greatly restrict the flexion-extension movement, a feature atypical of pterosaurs. The lateral part of the distal tibiotarsus, on the contrary, allows a very wide range of movement. Pterodaustro guinazui seems to have had an asymmetrical ankle joint, which could facilitate movements linked to wading behavior. We describe juvenile specimens that retain discrete distal tarsals II and III (common in the "non-pterodactyloid" pterosaurs), but also more mature specimens with completely fused distal tarsals II and III (a condition always observed in the late pterodactyloids). Moreover, the lateral distal tarsal (LDT) appears more robust in Pterodaustro than in Peteinosaurus or Dimorphodon, but shares a waisted shape with these taxa, unlike the more robust shape of the LDT of late pterodactyloids. The new information on the Pterodaustro ankle improves our anatomical knowledge of the basal Pterodactyloidea. [ABSTRACT FROM AUTHOR]

Feathers originate as protofeathers before birds, in pterosaurs and basal dinosaurs. What characterizes a feather is not only its outgrowth, but its barb cells differentiation and a set of beta-corneous proteins. Reticula appear concomitantly with feathers, as small bumps on plantar skin, made only of keratins. Avian scales, with their own set of beta-corneous proteins, appear more recently than feathers on the shank, and only in some species. In the chick embryo, when feather placodes form, all the non-feather areas of the integument are already specified. Among them, midventral apterium, cornea, reticula, and scale morphogenesis appear to be driven by negative regulatory mechanisms, which modulate the inherited capacity of the avian ectoderm to form feathers. Successive dermal/epidermal interactions, initiated by the Wnt/β-catenin pathway, and involving principally Eda/Edar , BMP, FGF 20 and Shh signaling, are responsible for the formation not only of feather, but also of scale placodes and reticula, with notable differences in the level of Shh, and probably FGF20 expressions. This sequence is a dynamic and labile process, the turning point being the FGF20 expression by the placode. This epidermal signal endows its associated dermis with the memory to aggregate and to stimulate the morphogenesis that follows, involving even a re-initiation of the placode. • Feather formation occurs by negative feedback mechanisms in non-feather areas. • FGF20 signal triggers epigenetic modifications of dermal fibroblasts potency. • Reticula are not scales and could not be considered as cutaneous appendages. • The first stage of feather evolution is suggested to correspond to a single barb. [ABSTRACT FROM AUTHOR]

'Tupuxuara deliradamus' was originally described as a tapejarid pterosaur from the Lower Cretaceous Romualdo Formation (Albian) of the Araripe Basin, Northeastern Brazil, and was regarded later by other authors as an indeterminate azhdarchoid. Whereas its taxonomic status remains controversial, its phylogenetic affinities were never investigated under computational analyses. Moreover, after its original description, other putative coeval pterosaurs have been described from Brazil. In the present study, these data are combined and we reconstruct the phylogenetic affinities of 'Tu. deliradamus' for the first time. It is recovered within Tapejarinae, nesting as the sister taxon to Caupedactylus ybaka. This result challenges the former assignation to Thalassodrominae. The holotype of 'Tu. deliradamus' shares a suit of traits of tapejarines, such as the lacrimal process of jugal being posteriorly inclined, the posterodorsal margin of the nasoantorbital fenestra forming an abrupt bend level with the dorsal margin of the orbit, and inclination of the quadrate with relation to the jugal bar is approximately 150°. Unfortunately, the fragmentary condition of SMKN PAL 6410 hampers a reliable taxonomic assignment at species level. Nevertheless, the new data supports its assignation to Tapejarinae indet. [ABSTRACT FROM AUTHOR]

The lack of any pterosaur living descendants creates gaps in the knowledge of the biology of this group, including its cervical biomechanics, which makes it difficult to understand their posture and life habits. To mitigate part of this issue, we reconstructed the cervical osteology and arthrology of three pterosaurs, allowing us to make inferences about the position of the neck of these animals at rest. We used scans of threedimensionally preserved cervical series of Anhanguera piscator, Azhdarcho lancicollis and Rhamphorhynchus muensteri for the reconstructions, thus representing different lineages. For the recognition of ligaments, joint cartilages, and levels of overlapping of the zygapophyses, we applied the Extant Phylogenetic Bracket method, based on various extant birds and on Caiman latirostris. We inferred that pterosaur intervertebral joints were probably covered by a thin layer of synovial cartilage whose thickness varied along the neck, being thicker in the posterior region. Ignoring this cartilage can affect reconstructions. According to the vertebral angulation, their neck was slightly sinuous when in rest position. Our analyses also indicate that pterosaurs had segmented and supra-segmented articular cervical ligaments, which could confer stabilization, execute passive forces on the neck and store elastic energy. [ABSTRACT FROM AUTHOR]

The pterosaur fossil record of Argentina is increasing in recent times, both in the number of localities and their temporal range. The new materials are found in levels that span from the Late Triassic to the Late Cretaceous in age. In this contribution we describe twenty isolated pterosaur teeth from the Cerro de los Leones locality (Picún Leufú, Neuquén Province), where the Lohan Cura Formation (Albian) widely crops out. A new, detailed analysis of these remains allowed us to detect a set of morphological features, such as the enamel texture, cross-section shape, crown curvature, and absence of sharp carinae, which suggests close affinities with Ornithocheiriformes. Moreover, with the large number of tooth specimens, a discrimination of three morphotypes based on the crown curvature, the basal cross-section shape, and the presence of carinae was carried out. We performed extensive morphological comparisons between different members of Ornithocheiriformes with the aim to test the hypothesis that the presence of these different morphotypes reflects distinct anatomical positions of the teeth in the jaws . Thus, considering the heterodont dentition of ornithocheiriforms, the tooth morphological classification proposed here represents a new methodology, not only to identify isolated ornithocheiriform teeth, but also to assign them to the rostral, medial, or the posterior portion of the tooth row. Finally, the evidence of ornithocheiriform pterosaurs in Cerro de los Leones has paleobiogeographical implications, allowing us to correlate it with other Albian faunas from South America, expanding our knowledge of the distribution of Early Cretaceous pterosaurs across southwestern Gondwana. [ABSTRACT FROM AUTHOR]

This article discusses the discovery of pterosaur teeth in the Albian deposits of Kaniv, Ukraine. The teeth belong to the clade Anhangueria, but due to their heterodont dentition and poor preservation, it is difficult to assign them to a specific genus or species. This finding is significant as it represents the first known occurrence of pterosaurs in Ukraine and contributes to the understanding of pterosaur diversity and biogeography in Eastern Europe. Further exploration of the area may yield more pterosaur and dinosaur material. [Extracted from the article]

Fragmentary but scientifically important pterosaur fossils have been reported in Lower Cretaceous strata such as the Jinju and Hasandong formations of South Korea. Recently, several large teeth and a second wing phalanx found in these strata have been suggested to have affinities with Boreopteridae, a clade in which has so far been reported only in the Yixian Formation of China. Here, the phylogenetic affinities of these proposed boreopterid specimens are reassessed, using two-dimensional geometric morphometric shape analyses. The morphometric analyses found the South Korean pterosaur teeth in different morphospaces from the Yixian Fm. boreopterids, and plot them closer to anhanguerians. An isolated second wing phalanx does plot close to a boreopterid Zhenyuanopterus longirostris in a morphospace defined by first two principal component axes, but taxa from different lineages are also plotted as closely, or even closer. Thus, there seems to be no clear evidence that these specimens belong to Boreopteridae, and the tooth fossils appear to be very different from those of established members of this clade. Therefore, the hypothesis that some South Korean pterosaur fossils can be referred to boreopterids, is here tentatively rejected [ABSTRACT FROM AUTHOR]

The Chaoyangopteridae is a clade of azhdarchoid pterosaurs that stands out in China, particularly in the Jehol Biota, as a Cretaceous group of medium-sized and high-crested pterosaurs. Herein, we describe a new species, Meilifeilong youhao gen. et sp. nov., based on two specimens, one tentatively referred to this taxon. This new species represents the most complete and well-preserved chaoyangopterid recorded to date. Along with a set of characters (low premaxillary crest above the nasoantorbital fenestra extending posteriorly, posterior premaxillary process arched and curving posteriorly, a slightly convex sternal articulation surface of coracoid, and a fibular shaft close to proximal articulation strongly arched posteriorly), this species also provides new information both on the unknown palatal region of this clade, and on the rarely preserved (in place) ear portion with stapes. Moreover, M. youhao sheds light on paleoecological aspects, while also giving new information about the taxonomic diversity of this peculiar group of Jiufotang pterosaurs. [ABSTRACT FROM AUTHOR]

A nearly complete skeleton of a Mesozoic pterosaur, which probably belongs to Jeholopterus (Anurognathidae), was discovered in the third member of the Sinuiju Formation, Paektho-dong, Sinuiju City, North Phyongan Province, Democratic People's Republic of Korea (DPRK). This find documents the first pterosaur fossil from the Mesozoic of DPRK. [ABSTRACT FROM AUTHOR]

The lack of any pterosaur living descendants creates gaps in the knowledge of the biology of this group, including its cervical biomechanics, which makes it difficult to understand their posture and life habits. To mitigate part of this issue, we reconstructed the cervical osteology and arthrology of three pterosaurs, allowing us to make inferences about the position of the neck of these animals at rest. We used scans of three-dimensionally preserved cervical series of Anhanguera piscator, Azhdarcho lancicollis and Rhamphorhynchus muensteri for the reconstructions, thus representing different lineages. For the recognition of ligaments, joint cartilages, and levels of overlapping of the zygapophyses, we applied the Extant Phylogenetic Bracket method, based on various extant birds and on Caiman latirostris. We inferred that pterosaur intervertebral joints were probably covered by a thin layer of synovial cartilage whose thickness varied along the neck, being thicker in the posterior region. Ignoring this cartilage can affect reconstructions. According to the vertebral angulation, their neck was slightly sinuous when in rest position. Our analyses also indicate that pterosaurs had segmented and supra-segmented articular cervical ligaments, which could confer stabilization, execute passive forces on the neck and store elastic energy.

Pterosaurs are an extinct group of Mesozoic flying reptiles, which exhibited high diversity with regard to their dentition. Although morphological features of pterosaur dentition have been described in detail in several contributions, the histology of tooth and tooth attachment tissues (i.e. periodontium) has been scarcely analysed to date for this clade. Here we describe and interpret the microstructure of the tooth and periodontium attachment tissues of Pterodaustro guinazui, a filter‐feeding pterodactyloid pterosaur from the Lower Cretaceous of Argentina. The histological analysis of the lower jaw and its filamentous teeth verifies that the geometry of the implantation corresponds to an aulacodont condition (i.e. teeth are set in a groove with no interdental separation). This pattern departs from that recorded in other archosaurs, being possibly also present in other, non‐closely related, pterosaurs. Regarding tooth attachment, in contrast to other pterosaurs, there is no direct evidence for gomphosis in Pterodaustro (i.e. the absence of cementum, mineralized periodontal ligamentum and alveolar bone). Nevertheless, the current evidence for ankylosis is still not conclusive. Contrary to that reported for other archosaurs, replacement teeth are absent in Pterodaustro, which is interpreted as evidence for monophyodonty or diphyodonty in this taxon. Most of the microstructural features are possibly related to the complex filter‐feeding apparatus of Pterodaustro and does not appear to represent the general pattern of pterosaurs. [ABSTRACT FROM AUTHOR]

The pterosaur assemblage of the mid-Cretaceous Kem Kem Group of Morocco is reviewed. This analysis examines their taxonomy, palaeoecology and palaeobiology with comments on taphonomy. New material permits the rediagnosis of the azhdarchoids Alanqa saharica and Afrotapejara zouhrii. Several specimens are reported that do not fit within the paradigms of previously named taxa. They represent three distinct jaw morphotypes, but are not assigned to new taxa here. The assemblage is highly diverse, including four tooth-bearing taxa assigned to Ornithocheiridae and five named taxa and three additional morphotypes assigned to Azhdarchoidea. The Kem Kem Group assemblage is the most diverse for any pterosaur-bearing fluvial deposit and one of the most diverse of any pterosaur assemblage. The assemblage is heavily biased in terms of preservation with an as yet unexplained high abundance of jaw fragments. We highlight the importance of fragmentary material in pterosaur studies. [ABSTRACT FROM AUTHOR]

An incomplete, yet remarkably-sized dentated rostrum and associated partial cervical vertebrae of a pterosaur (ML 2554) were recently discovered from the Late Jurassic (Late Kimmeridgian-Early Tithonian) Lourinhã Formation of Praia do Caniçal, of central west Portugal. This specimen exhibits features such as a spatulated anterior expansion of the rostrum, robust comb-like dentition, and pronounced rims of the tooth alveoli, indicating gnathosaurine affinities. Based on its further unique tooth and dentary morphology, a new genus and species, Lusognathus almadrava gen. et spec. nov., is proposed, making this the first named pterosaur species found within Portugal. The presence of this taxon adds yet another element to the fluvio-deltaic lagoonal environment that has been suggested as representative of the Lourinhã Formation in the Late Jurassic, further contributing to the diversity and distribution of gnathosaurines worldwide. [ABSTRACT FROM AUTHOR]

An incomplete, yet remarkably-sized dentated rostrum and associated partial cervical vertebrae of a pterosaur (ML 2554) were recently discovered from the Late Jurassic (Late Kimmeridgian-Early Tithonian) Lourinhã Formation of Praia do Caniçal, of central west Portugal. This specimen exhibits features such as a spatulated anterior expansion of the rostrum, robust comb-like dentition, and pronounced rims of the tooth alveoli, indicating gnathosaurine affinities. Based on its further unique tooth and dentary morphology, a new genus and species, Lusognathus almadrava gen. et spec. nov., is proposed, making this the first named pterosaur species found within Portugal. The presence of this taxon adds yet another element to the fluvio-deltaic lagoonal environment that has been suggested as representative of the Lourinhã Formation in the Late Jurassic, further contributing to the diversity and distribution of gnathosaurines worldwide.

Bogolubovia orientalis, the first pterosaur taxon described from Russia, was known for more than a hundred years from a single specimen, the posterior fragment of the middle cervical vertebra from the Upper Cretaceous (upper Campanian) Rybushka Formation at Malaya Serdoba locality in Penza oblast, Russia. First classified as a pteranodontid, Bogolubovia was long thought to be an azhdarchid, and only very recently has it been again reclassified as a pteranodontid. Here, we describe the second pterosaur vertebra from the Malaya Serdoba locality, an atlantoaxis, which shows distinct pteranodontid characters, such as round cotyle, lack of hypapophysis, rudimentary diapophysis placed anterior to the lateral pneumatic foramen, and pair of posterior lateral pneumatic foramina. The pteranodontid characters of the holotype middle cervical vertebra include high neural arch, which is higher than the centrum and has the postzygapophyses placed well above the condyle, and the large posterior lateral foramina, similar in size with the posterior opening of the neural canal. Both vertebrae can be assigned to the same taxon, Bogolubovia orientalis. Bogolubovia can be distinguished from the pteranodontids Pteranodon and Volgadraco and thus is considered a valid taxon. [ABSTRACT FROM AUTHOR]

Pterosaurs evolved a broad range of body sizes, from small-bodied early forms with wingspans of mostly 1–2 m to the last-surviving giants with sizes of small airplanes. Since all pterosaurs began life as small hatchlings, giant forms must have attained large adult sizes through new growth strategies, which remain largely unknown. Here we assess wing ontogeny and performance in the giant Pteranodon and the smaller-bodied anurognathids Rhamphorhynchus, Pterodactylus and Sinopterus. We show that most smaller-bodied pterosaurs shared negative allometry or isometry in the proximal elements of the fore- and hindlimbs, which were critical elements for powering both flight and terrestrial locomotion, whereas these show positive allometry in Pteranodon. Such divergent growth allometry typically signals different strategies in the precocial–altricial spectrum, suggesting more altricial development in Pteranodon. Using a biophysical model of powered and gliding flight, we test and reject the hypothesis that an aerodynamically superior wing planform could have enabled Pteranodon to attain its larger body size. We therefore propose that a shift from a plesiomorphic precocial state towards a derived state of enhanced parental care may have relaxed the constraints of small body sizes and allowed the evolution of derived flight anatomies critical for the flying giants. [ABSTRACT FROM AUTHOR]

As the lowest horizon of the Early Cretaceous Jehol Biota, the Huajiying Formation of the northern Hebei Province, China is rich with avians and feathered dinosaurs, but lacks pterosaur record. Here the first pterosaur fossil is reported from the Huajiying Formation. The new pterosaur specimen is characterised by an unusual pedal configuration of a short and spread metatarsus with elongate digits, showing a close resemblance to the dentulous Ornithocheiroidea. The pedal configuration is diverse in pterosaurs, and is often associated with ecological adaptations. In contrast to the general pattern of the elongate metatarsus and short digits, the elongate digits of the dentulous ornithocheiroids (e.g., boreopterids and istiodactylids) might offset the shortened metatarsus to enlarge the pedal surface for paddling, representing a new strategy in adaptation to the aquatic environment. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

[Display omitted] The Gondwanan pterosaur record is scarce when compared with that of Laurasia and is reviewed here. The majority of Gondwanan pterosaur remains are derived from South America; however, the relative richness of the South American record compared with other Gondwanan continents is largely a result of the 'Lagerstätten' effect. Nevertheless, the South American pterosaur assemblage represents the most speciose and diverse known from Gondwana, with several lineages represented, including the Raeticodactylidae, Rhamphorhynchoidea, Darwinoptera, Ctenochasmatidae, Gnathosaurinae, Nyctosauridae, Ornithocheiridae, Tapejaridae, Thalassodromidae, Dsungaripteridae, Chaoyangopteridae and Azhdarchidae. Gondwanan pterosauromorphs are known only from South America. From Africa rhamphorhynchids, archaeopterodactyloids, pteranodontians, nyctosaurids, ornithocheirids, tapejarids, dsungaripteroids, chaoyangopterids, and azhdarchids have been reported. The Arabian Peninsula has produced nyctosaurids, an istiodactyliform, ornithocheirids and azhdarchids. Non-pterodactyloid pterosaurs have been reported from India. A possible azhdarchid has been reported from Madagascar and rhamphorhynchids are known from isolated teeth. The Antarctic pterosaur assemblage also comprises isolated remains of indeterminate pterodactyloids, and a possible indeterminate rhamphorhynchoid. The pterosaur record from East Gondwana comprises ornithocheirids, azhdarchids and a possible ctenochasmatoid from Australia, as well as azhdarchids from New Zealand. Although our understanding of Gondwanan pterosaurs has greatly improved within the last three decades, the discovery and description of more specimens, particularly from Antarctica and East Gondwana, will enhance our understanding of pterosaurian biodiversity and palaeobiogeography. [ABSTRACT FROM AUTHOR]

Protective coloration is observed in numerous extant cockroach species and is prevalent among insects. Such coloration can signal nonprofitability of prey (aposematic) or serve as a camouflage (disruptive). An apparent aposematic isolated macula is identified here among the cockroach Facioblatta perfidia gen. et sp. n. (Liberiblattinidae) from Northern Myanmar amber. In total, 9 and 10 general coloration patterns related to spot-like patterns among extant and fossil species, respectively, are identified. Potential cockroach predators targeted with these patterns varied from dragonflies, small Jurassic pterosaurs and lizards, to Cretaceous and modern frogs, birds and insectivores. Patterns asynchronously appeared throughout the taxonomic spectrum suggesting that the elimination from predators combined with environmental factors influenced the spread of protective coloration among cockroaches. [ABSTRACT FROM AUTHOR]

An isolated jaw fragment from the Late Cretaceous (Cenomanian) Cambridge Greensand Member of the West Melbury Marly Chalk Formation previously identified as a cestraciontid shark fin spine is referred to the pterosaur clade Azhdarchoidea on account of its lateral and occlusal foramina and edentuly. The specimen differs from the azhdarchoid Ornithostoma sedgwicki from the same deposit in having flat lateral surfaces and an acute dorsal/ventral apex. The specimen is similar in overall morphology to CAMSM B40085 from the same horizon and probably represents the corresponding jaw but from a different individual. Likely these specimens represent a new taxon but are considered too fragmentary to diagnose at present. A remarkably similar and distinctive morphology is found in unnamed pterosaur jaws from the Kem Kem Group (?Albian-Cenomanian) of Morocco, supporting the idea of faunal similarity between these two distant localities. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Across the evolution of powered flight, the ecological niche of aerial insectivore has been occupied by members of the three volant vertebrate clades—Aves and Chiroptera, and the first known volant vertebrates, pterosaurs. However, morphological and quantitative evidence to support pterosaurs exhibiting this ecology remains scant. Anurognathids are an unusual group of pterosaurs in which the skull exhibits the unique morphology of being mediolaterally expanded, so much so that their skulls may be wider than rostrocaudally long. Here, we conduct quantitative comparative cranial measurements and dental morphology in anurognathids against extant avian and chiropteran taxa, respectively, with ecologies and behaviors that are similar to predicted putative behaviors of anurognathids. Comparative analyses of both skull and dental morphology suggest anurognathid specimens in similar morphospaces as insectivorous crepuscular and nocturnal extant volant taxa. Our results support that this unique group of pterosaurs likely occupied a niche of mid‐flight insectivorous capture in low‐light conditions. [ABSTRACT FROM AUTHOR]

Three ichnospecies of the Late Jurassic trace fossil genus Rhamphichnus were first described and interpreted as the walking tracks of non-pterodactyloid pterosaurs like Rhamphorhynchus. This despite not resembling any previously identified pterosaur tracks and having a morphology unmatched by pterosaur skeletal elements. To fit the pterosaurian model, elongated imprints of R. pereiraensis and R. lafaurii , displaying four or five digit impressions were interpreted as manus prints, while shorter, five-digit prints were interpreted as imprints made by pedes with dislocated metatarsals and disarticulated phalanges. Comparison of published images and descriptions of Rhamphichnus ispp. to skeletal elements of six contemporaneous non-pterodactyloid taxa, skeletons and tracks from pterodactyloid pterosaurs, and modern and ancient lepidosaurs and crocodilians suggests an alternative interpretation. R. crayssacensis closely resembles crocodilian (Crocodylopodus (Sustenodactylus) isp.) and crocodylomorph (Batrachopus isp.) tracks; its holotype trackway was found 50 cm away from and parallel to a crocodilian swimming trackway with the same sized feet, possibly made by the same individual. R. pereiraensis and R. lafaurii strongly resemble lepidosaurian tracks and match the size and morphology of contemporary rhynchocephalians. Prints originally interpreted as manual and pedal in R. pereiraensis and R. lafaurii are reinterpreted and transposed in light of new data from pterosaurian, lepidosaurian, and crocodilian tracks and anatomy. Identification of fossil trackmakers depends on comparisons of a wide range of candidate taxa and elimination of those that cannot be considered further. With this reinterpretation of Rhamphichnus , there are no non-pterodactyloid pterosaurian tracks yet identified in the fossil record. [ABSTRACT FROM AUTHOR]

Major transformations in the locomotor system of archosaurs (a major clade of reptiles including birds, crocodiles, dinosaurs, and pterosaurs) were accompanied by significant modifications to ankle anatomy. How the evolution of such a complex multi‐joint structure is related to shifts in ankle function and locomotor diversity across this clade remains unclear and weakly grounded in extant experimental data. Here, we used X‐ray Reconstruction of Moving Morphology to reconstruct skeletal motion and quantify the sources of three‐dimensional ankle mobility in the American alligator, a species that retains the ancestral archosaur ankle structure. We then applied the observed relationships between joint excursion and locomotor behaviors to predict ankle function in extinct archosaurs. High‐resolution reconstructions of Alligator skeletal movement revealed previously unseen regionalized coordination among joints responsible for overall ankle rotation. Differences in joint contributions between maneuvers and steady walking parallel transitions in mobility inferred from the ankle structure of fossil taxa in lineages with more erect hind limb postures. Key ankle structures related to ankle mobility were identified in the alligator, which permitted the characterization of ancestral archosaur ankle function. Modifications of these structures provide morphological evidence for functional convergence among sublineages of bird‐line and crocodylian‐line archosaurs. Using the dynamic insight into the internal sources of Alligator ankle mobility and trends among locomotor modes, we trace anatomical shifts and propose a mechanistic hypothesis for the evolution of ankle structure and function across Archosauria. [ABSTRACT FROM AUTHOR]

Excavation of a green breccia lens in the otherwise shaley Hudspeth Formation of central Oregon recovered a surprising variety of fossils of different kinds: plant impressions, mollusc shells, and vertebrate bones and teeth. Some ammonites, such as Mortoniceras inflatum, which date the deposit as late Albian (103 Ma), were preserved with shell intact below, but dissolved above back to sutures. Intact ammonites were outnumbered by angular ammonite fragments in the size range 1–2 cm. Marine clams, snails and ammonites were found in the same bed as a variety of fossil plants, including horsetails, ferns, cycads, and conifers. Also recovered were bones of fish, ichthyosaurs, dinosaurs, and pterosaurs. Orientation of large fossil logs and branches reveal derivation from the east, where a shoreline of shingle beaches and alluvial fans created the interfingering Gable Creek Conglomerate. The matrix-supported green breccia is massive and ungraded, and interpreted as a mass flow deposit. Enrichment in phosphorus compared with shale above and below is evidence that its fine-grained component includes guano. This guano and unusual fragmentation of ammonites are interpreted as evidence that the Oregon pterosaur, Bennettazhia oregonensis, was a mollusc-eater and formed large colonies on nearby cliffs, like modern gull rookeries. [ABSTRACT FROM AUTHOR]

Tapejarids are edentulous pterosaurs particularly abundant in the Chinese Jiufotang Formation, counting with over 10 described specimens and dozens of undescribed ones. A total of seven nominal tapejarid species (within two genera) have been proposed, though it is disputed how many of those are valid instead of sexual or ontogenetic morphs of fewer, or a single, species. However, detailed revisions of the matter are still lacking. In the present work, we provide a specimen-level survey of anatomical variation in previously described Jiufotang tapejarid specimens, as well as of six new ones. We present qualitative and morphometric comparisons, aiming to provide a basis for a taxonomic reappraisal of the complex. Our results lead us to interpret two Jiufotang tapejarid species as valid: Sinopterus dongi and Huaxiadraco corollatus (gen. et comb. nov.). Our primary taxonomic decisions did not rely around cranial crest features, which have typically been regarded as diagnostic for most of these proposed species albeit ever-growing evidence that these structures are highly variable in pterosaurs, due to ontogeny and sexual dimorphism. However, a reassessment of premaxillary crest variation in the Sinopterus complex reveals that while much of the observed variation (crest presence and size) can easily be attributed to intraspecific (ontogenetic and sexual) variation, some of it (crest shape) does seem to represent interspecific variation indeed. A phylogenetic analysis including the species regarded as valid was also performed. [ABSTRACT FROM AUTHOR]

The origin of the air sac system present in birds has been an enigma for decades. Skeletal pneumaticity related to an air sac system is present in both derived non-avian dinosaurs and pterosaurs. But the question remained open whether this was a shared trait present in the common avemetatarsalian ancestor. We analyzed three taxa from the Late Triassic of South Brazil, which are some of the oldest representatives of this clade (233.23 ± 0.73 Ma), including two sauropodomorphs and one herrerasaurid. All three taxa present shallow lateral fossae in the centra of their presacral vertebrae. Foramina are present in many of the fossae but at diminutive sizes consistent with neurovascular rather than pneumatic origin. Micro-tomography reveals a chaotic architecture of dense apneumatic bone tissue in all three taxa. The early sauropodomorphs showed more complex vascularity, which possibly served as the framework for the future camerate and camellate pneumatic structures of more derived saurischians. Finally, the evidence of the absence of postcranial skeletal pneumaticity in the oldest dinosaurs contradicts the homology hypothesis for an invasive diverticula system and suggests that this trait evolved independently at least 3 times in pterosaurs, theropods, and sauropodomorphs. [ABSTRACT FROM AUTHOR]