Dinosaur trackway fossils in the Otog Field Geological Heritage Museum, Inner Mongolia, China, have suffered severe weathering, with extensive surface powdering and granular disintegration. This study evaluated three TEOS-based hybrid materials modified with dodecyltrimethoxysilane (WD10), bis(triethoxysilyl)ethane (BEQ), and bis(triethoxysilyl)octane (BOQ), designated as 10%W5, 10%E5, and 10%O3. Performance was assessed in terms of penetration depth, hydrophobicity, mechanical strength, color difference, vapor permeability, salt resistance, and freeze–thaw durability. All three materials effectively improved the fossils’ properties, with 10%W5 showing the best performance: penetration depth of 28.4 mm within 5 min, water absorption reduced to 0.48%, contact angle of 125.73°, compressive strength improved by 67.73%, and excellent salt and freeze–thaw resistance. The exceptional performance of 10%W5 is attributed to its homogeneous and discontinuous siloxane gel network, which enhances intergranular bonding while preserving pore connectivity and vapor permeability.

The maximum locomotor capabilities of theropod dinosaurs have long been a subject of considerable scholarly, primarily due to the lack of contemporary species for direct comparison. Biomechanical modeling and the analysis of dinosaur trackways have yielded significant theoretical insights into this area of research. This study investigates the running speed of a mid-sized theropod dinosaur trackway recently identified in the Otog region of Inner Mongolia, and it juxtaposes these findings with other running theropod trackways from diverse various global locations utilizing standardized inference methodologies. The results indicate that the trackmaker was capable of achieving a running speed of 45 or 41±4.9 km/h, thereby establishing it as the fastest-running theropod trackway documented from the Cretaceous period. Additionally, this paper reviews biomechanical investigations concerning the maximum running speeds of theropod dinosaurs and illustrates that the inferred speed of this mid-sized theropod aligns with the predictions of the majority of biomechanical models, thereby providing compelling new evidence to enhance our understanding of the locomotor capabilities of mid-sized theropods.

The Jurassic Period was characterized by the dominance of dinosaurs and the rise of early mammals, with the Yanliao Biota (∼167-157 Ma) in East Asia notable for its exceptional fossil preservation and diverse life forms. However, the drivers of the flourishing of the Yanliao Biota remain unclear. Here, we reconstruct the palaeoclimate and habitat characteristics of the Yanliao Biota by using sedimentary facies analysis, organic carbon-isotope data, palynological records, source weathering trends and climate simulations from the Community Earth System Model CESM 1.2.2. The studied sedimentary successions are well constrained to the Middle Jurassic based on carbon-isotope stratigraphic correlation and published tuff zircon U-Pb ages. Our findings reveal a regional climate shift in the late Bathonian, transitioning from wet to sub-humid conditions, as evidenced by an increase in gymnosperm pollen, a marked decline in coal seams and reduced weathering intensity. Sedimentological evidence further supports a synchronous facies change from ever-wet fluvial-delta systems to seasonally active alluvial plains. This climate shift aligns with simulation results and coincides temporally with the initial flourishing of the Yanliao Biota. We propose that this shift, associated with lithospheric extension in the Yanliao region, increased landscape heterogeneity and habitat diversity, fostering biological evolution through ecological isolation and allopatric speciation, ultimately driving the diversification of the Yanliao Biota.

Pterosaur remains are rare from the lowermost Cretaceous, hampering our understanding of the taxonomic and morphological diversities of pterosaurs during this period. The Lower Cretaceous Tugulu Group in Wuerho, China is renowned for hosting the Wuerho Pterosaurian Fauna (WPF), which has so far yielded numerous fossil remains of two dsungaripterid pterosaurs, Dsungaripterus weii and Noripterus complicidens. Here we report a partial ornithocheiromorph humerus from the WPF, representing a deeply divergent clade from Dsungaripteridae. The scarcity of ornithocheiromorphs from the WPF might be interpreted by niche partitioning with dsungaripterids. Meanwhile, we also report a U-Pb zircon age of 134.27 ± 0.36 Ma dated by LA-ICP-MS for the tuffaceous layer at the uppermost part of the Shengjinkou Formation, confirming the Valanginian age of the WPF presented by a previous study. The Wuerho region is one of the few localities producing abundant pterosaur fossils and the only one with an earliest Cretaceous age. The new finding here also suggests that Ornithocheiromorpha had rapidly diversified and achieved a global distribution during the earliest Cretaceous, presumably through a series of modifications on the locomotor apparatus including the warped deltopectoral crest of the humerus, which might substantially improve their flight efficiency.

The Wukongopteridae is an important pterosaur clade from the Yanliao Biota, combining features of basal and derived pterosaurs. So far, the Wukongopteridae consists of five species divided into three genera: Wukongopterus lii, Darwinopterus modularis, Darwinopterus linglongtaensis, Darwinopterus robustodens, and Kunpengopterus sinensis. Here we report a new species, Darwinopterus camposi sp. nov., based on an almost complete skeleton (IVPP V 17957). The new species is referred to Darwinopterus due to the presence of an elongated posterior region of the skull and the bony premaxillary crest that starts about the anterior margin of the nasoantorbital fenestra. It differs from all other wukongopterids by having the dorsal margin of the premaxillary crest straight, without an extensive dorsal projection and presenting a smooth lateral surface. Furthermore, D. camposi sp. nov. has eighteen and fourteen teeth on each side of the upper and lower jaws, respectively, and the fourth phalanx of the wing finger shorter than the first. IVPP V 17957 shows some fused postcranial bones, like the extensor tendon process to the first wing finger phalanx, but also has unfused premaxilla and frontal, which provides further information about wukongopterid ontogeny.

A new clutch of a rarely described oospecies, Nanhsiungoolithus chuetienensis is detailed in this work. The clutch contains 14 eggs radially arranged in two concentric rings, representing the most complete clutch of N. chuetienensis yet described. The morphology and microstructure of this new specimen align with those of the previously studied N. chuetienensis specimens. Notably, the eggshell displays reticulatituberculate ornamentation, introducing a new characteristic for this oospecies. The specimen also reveals microstructural variation along the egg body, including thickness, mammillae shape, and EBSD characteristics. Combining prismatic morphotype, reticulatituberculate ornamentation, and broad mammillae, this study amended the diagnosis of Nanhsiungoolithus. Importantly, Montanoolithus, Reticuloolithus, and Paraelongatoolithus, which were presumed to be putative dromaeosaurid eggs, share this combination and are therefore considered junior synonyms of Nanhsiungoolithus. As a result, the oogenus Nanhsiungoolithus now belongs to the oofamily Montanoolithidae. The similarity of the clutch structure between montanoolithid and elongatoolithid eggs indicates that dromaeosaurids may share a similar clutch structure to that of oviraptorids.

The Compsognathidae was originally considered an early-diverging clade of coelurosaur theropods. However, recent study suggests that Compsognathidae is not monophyletic. Here, we describe two new compsognathid-like species, Sinosauropteryx lingyuanensis sp. nov. and Huadanosaurus sinensis gen. et sp. nov. from the Lower Cretaceous Yixian Formation of Dawangzhangzi (Lingyuan, Western Liaoning, China). The phylogenetic results indicate that all compsognathid-like theropods from the Early Cretaceous Jehol Biota form a monophyletic group Sinosauropterygidae nested among early-diverging coelurosaurs. Morphological comparison between various species of sinosauropterygids from the Early Cretaceous of Northeast China, combined with the phylogenetic results, suggests that at least three distinct hunting strategies were present among coeval species. The diversification of theropods should be attributed to the landscape caused by the destruction of the North China craton.

Abundant and diverse pterosaur records have been reported from the Jehol Biota since the end of the last century, including an early reported member, Haopterus gracilis, from the Yixian Formation. The referral of Haopterus gracilis has been a subject of debate since its discovery. Various phylogenetic analyses have suggested different positions for Haopterus gracilis, including the sister taxon of the Ornithocheiroidea or placed differently in the Pteranodontoidea. Recent research has proposed that Haopterus gracilis is the sister-taxon of the Lebanese istiodactyliform Mimodactylus libanensis. Here we redescribe the holotype and only specimen of Haopterus gracilis, a relatively complete skeleton of a juvenile individual in detail using Micro-CL scanning. Haopterus possesses several pteranodontoid features including a stout scapula shorter than the coracoid, a sternum with a constriction posterior to the sternocoracoid articulations, and humeri with trapezoidal deltopectoral crests and constricted mid-shafts. A close affinity between Haopterus and istiodactylids has been suggested by several researchers, whereas some features of Haopterus revealed here distinguish Haopterus from istiodactylids, including the low skull with a long rostrum occupying more than half the skull length anterior to the jaw articulation, and a long tooth row with different tooth morphologies. The phylogenetic position of Haopterus was reevaluated by utilizing a more comprehensive character matrix derived from three previous matrices. The new analysis revealed Haopterus in the Pteranodontoidea and, within this clade, it was an istiodactyliform. The study of Haopterus holds potential significance in enhancing our understanding of the morphology and taxonomy of short-toothed pteranodontoids.

The Istiodactyliformes, a group of short-toothed Cretaceous pterosaurs including istiodactylids and their relatives, have mostly been reported from the Jehol Biota of Northeastern China. Recently, a new specimen of Hongshanopterus lacustris, an istiodactyliform from the Lower Cretaceous Jiufotang Formation, has been unveiled. Here we present a detailed description of a new specimen, which comprises most of the skull, the mandible, several cervical vertebrae, and plenty of isolated teeth, providing additional anatomical information of this taxon. We also present the comprehensive redescription of the holotype of Nurhachius ignaciobritoi, the first reported istiodactylid from China. Most of the previously suggested variances between Nurhachius specimens are here found invalid to separate different taxa, but the holotype has a shorter rostrum compared with others. Additional morphological information revealed by the new specimen and redescription further supports the affinity between Hongshanopterus and istiodactylids, and between istiodactylids and other pteranodontoids, but istiodactylids possess narrower cervical vertebrae compared with anhanguerians.

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.

Ornithocheiroidea was a globally diverse group of pterosaurs during the Cretaceous. However, well-documented ornithocheiroids are highly derived, hampering our understanding on the morphological evolution of this clade. Dsungaripterus weii Young, 1964 from the Lower Cretaceous Tugulu Group (Valanginian) of the Junggar Basin is an iconic early member of Ornithocheiroidea. Dsungaripterus is known from numerous three-dimensionally preserved specimens, ranging from isolated bones to partially articulated individuals. Here we provide a comprehensive description of the postcranium of Dsungaripterus. We find that Dsungaripterus has many autapomorphies in the postcranial skeleton parallelling its unique skull, including the asynchronous fusion between the sacrum and pelvis and a posterodorsal fossa of the humerus with a paper-thin bone wall. Dsungaripterus also displays some plesiomorphic features of Ornithoecheiroidea, for example, limb bones with relatively thick bone walls, variably reduced pneumatic features in cervical vertebrae and appendicular skeletons, absence of spinoprezygapophyseal and spinopostzygapophyseal ridges in middle-series cervical vertebrae, at least one metacarpal articulating with the distal syncarpal, and a distally displaced adductor ridge on the femur. Additionally, Dsungaripterus possesses some unexpected features possibly convergent with other members of Ornithocheiroidea. Although the postcranial skeletons of Dsungaripterus are represented by osteologically mature specimens, notable morphological variation is present. Functional reconstructions of several aspects of the postcranial skeleton of Dsungaripterus are elucidated, including the arrangement of the metacarpophalangeal region during terrestrial locomotion. Niche partitioning between the two dsungaripterids from the Tugulu Group of Wuerho, Dsungaripterus and Noripterus, is supported by their distinct dentitions, neck morphology, and limb proportions.

Electron backscatter diffraction (EBSD) has been widely used in recent studies of eggshells for its convenience in collecting in situ crystallographic information. China has a wide variety of dinosaur eggshells, although nearly none have been studied with this technique. Elongatoolithid eggs include many oogenera, although the microstructural differences of some were not highly appreciated, leading to several parataxonomic problems. In this paper, we surveyed seven elongatoolithid oogenera in China using EBSD in order to acquire more information about their microstructural variation. It is shown in this paper that in some elongatoolithid eggshells, scaly calcite grains that form the squamatic ultrastructure are not the only form of calcite in the continuous layer. Large columnar grains separated by high-angled grain boundaries and slender subgrains separated by radially arranged low-angled grain boundaries could exist in certain areas of the eggshells such as Macroolithus and Macroelongatoolithus. This paper discusses the criteria for identifying squamatic ultrastructure and proposes type I (rich in rugged high-angled grain boundaries) and type II (rich in both rugged high- and low-angled grain boundaries) squamatic ultrastructures. A pathological layer is found in Undulatoolithus pengi. An external zone is identified in the eggshell of Heishanoolithus changii, which does not support its position within the oofamily Elongatoolithidae. We argue that Paraelongatoolithus no longer belongs to Elongatoolithidae based on a combination of reticulated ornamentation, columnar continuous layer, and acicular mammillae. The high structural variation in elongatoolithid eggshells also implies that it may be inappropriate to relate all previous elongatoolithid eggshells to oviraptorosaurs and assume they are non-monophyletic.

The wrist of extant birds is highly specialized which permits folding of the forelimb in order to protect the pennaceous feathers when they are relaxed. This mechanism is absent in most non-avian theropods and is unknown in oviraptorosaurs because of the rarity of the specimens with well-preserved wrist. Here we give a detailed description of the wrist of two three-dimensionally preserved oviraptorosaurian Heyuannia huangi specimens from the Upper Cretaceous in Southern China. Heyuannia huangi possesses a highly specialized wrist with a strongly dorsoventrally compressed distal ulna, a larger radiale angle and a strongly convex semilunate carpal. The morphology of its wrist suggests that the distal ulna would not hinder the rotation of the manus, resulting in the smallest angle between the manus and the ulna being less than 90 degrees. The combination of the morphology of the wrist of oviraptorosaurs and the phylogenetic result indicates functional convergence in the wrist of oviraptorids and extant birds.

Legacy per- and polyfluoroalkyl substances (PFASs) are a worldwide health concern due to their potential bioaccumulation and toxicity in humans. A variety of perfluoroether carboxylic acids (PFECAs) have been developed as next-generation replacements of legacy PFASs. However, information regarding their possible environmental and human health risks is limited. In the present study, we explored the effects of PFECAs on mice based on long-term exposure to environmentally relevant doses of perfluoro-3,5,7,9,11-pentaoxadodecanoic acid (PFO5DoDA). Results showed that PFECAs exposure suppressed many cellular stress signals and resulted in hepatomegaly. PFO5DoDA acted as an agonist of the peroxisome proliferator-activated receptor (PPAR) in vitro and modulated PPAR-dependent gene expression in the liver. Importantly, PFECAs had an inhibitory effect on the glucocorticoid receptor (GR), which may contribute to the extensive suppression of stress signals. Of note, the GR suppression induced by PFECAs was not reported by legacy perfluorooctanoic acid (PFOA). PFO5DoDA-induced changes in both GR and PPAR signals remodeled hepatic metabolic profiles, including decreased fatty acids and amino acids and increased β-oxidation. Mechanistically, PFO5DoDA inhibited GR transactivation by degradation of GR proteins. Our results emphasize the potential risk of PFECAs to human health, which were introduced to ease concerns regarding legacy PFASs.

The Tapejaridae is an exquisite toothless pterodactyloid clade of pterosaurs that flourished in the Jehol Biota with well-developed premaxillary and dentary crests, large nasoantorbital fenestra and downward rostrum. Since Sinopterus dongi has been reported from the Jiufotang Formation, most of the Chinese tapejarids were discovered from this geological unity. Eopteranodon lii, the first tapejarid from the Yixian Formation, was formerly referred to the Pteranodontidae and is now assigned to the Tapejaridae. Here, Eopteranodon yixianensis sp. nov. is reported from this latter formation as differing from all other known tapejarids by largest rostral value (10.88); the nasoantorbital fenestra is not as long as that of other tapejarids (accounting for 35% of the skull length). Furthermore, the skull's length/height ratio is ∼5.67; the lower bony crest occupies ∼42% of the total mandibular length; the humerus and the fourth wing phalanx length ratio is ∼2.17 and the downturn rostral angle is ∼17°. New data on the evolution (morphology and geographical origin) of the group is also provided.

The toothed members of Pterosauria display an extremely wide range of tooth morphologies that supported a variety of feeding habits. Histological studies on the teeth of different pterosaur clades are potentially valuable in understanding the development of their tooth diversity. In this study, we used histological sections and scanning electron microscopy to describe and interpret the tooth microstructure of Hamipterus (Pterodactyloidea). Our analysis is based on seven teeth of Hamipterus (six isolated and one from a skull) from the Lower Cretaceous collected in Hami, China. Our results show that the enamel on the tooth crown is thin (~25 μm) in Hamipterus and covers only approximately half of the tooth crown. This thin enamel of the Hamipterus tooth makes it vulnerable and often becomes damaged during taphonomic and diagenetic processes. The radicular pulp inside the conical-shaped root shows a spindle space with a small foramen at the bottom, while the coronal pulp shows a small tunnel (100-140 μm in diameter). We estimate that the small teeth of Hamipterus likely took approximately 80 days to form. Furthermore, the tooth has Andresen lines, which represent 7-15 days period. For stable articulation of the tooth in the alveolus, the thick cellular cementum is concentrated on the lingual side of the root. The acellular cementum (~40 μm thick) layer runs from the root to the partial tooth crown.

As one of the mysteries volant vertebrates, pterosaurs were completely extinct in the K-Pg extinction event, which hampered our understanding of their flight. Recent studies on pterosaur flight usually use birds as analogies, since their shoulder girdle share many features. However, it was also proposed that these two groups may differ in some critical flight mechanisms, such as the primary muscles for the upstroke of the wings. Here, we describe and characterize the detail features of the pectoral girdle morphology and histology in Hamipterus from the Early Cretaceous of Northwest China for the first time. Our research reveals that the scapula and coracoid of Hamipterus form a synostosis joint, representing a distinct pectoral girdle adaption during pterosaur flight evolution, different from that of birds. The residual of the articular cartilage of the glenoid fossa supports the potential for cartilage tissue preservation in this location. The morphology of the acrocoracoid process of Hamipterus indicates it may work as a pulley for M. supracoracoideus as the main power of flight upstroke resembles that of birds. But the saddle type of the shoulder joint of the pterosaur may limit the rotation of the humerus head, suggesting a particular mechanism to control the angle of attack unlike birds. The presence of both the similarity and differences between the flight apparatus of pterosaurs and birds are highlighted in our research, which may be related to the flight mechanism and forelimb functional adaption. The distinctive feature of the flight apparatus of pterosaur should be treated with caution in future research, to better understand the life of this unique extinct volant vertebrate.