The polymorphic nature of InSe leads to excellent phase-dependent physical properties including ferroelectricity, photoelectricity, and especially the intriguing phase change ability, making the precise phase modulation of InSe of fundamental importance but very challenging. Here, the growth of InSe with desired-phase is realized by temperature-controlled selenization of van der Waals (vdW) layered bulk γ-InSe. Detailed results of Raman spectroscopy, scanning electron microscopy (SEM), and state-of-the-art spherical aberration-corrected transmission electron microscopy (Cs-TEM) clearly and consistently show that β-InSe, 3R α-InSe, and 2H α-InSe can be perfectly obtained at ≈270, ≈300, and ≈600 °C, respectively.
View Article and Find Full Text PDFMajor groups of jawed vertebrates exhibit contrasting conditions of dermal plates and scales. But the transition between these conditions remains unclear due to rare information on taxa occupying key phylogenetic positions. The 425-million-year-old fish Entelognathus combines an unusual mosaic of characters typically associated with jawed stem gnathostomes or crown gnathostomes.
View Article and Find Full Text PDFPterosaurs, the earliest flying tetrapods, are the subject of some recent quantitative macroevolutionary analyses from different perspectives. Here, we use an integrative approach involving newly assembled phylogenetic and body size datasets, net diversification rates, morphological rates, and morphological disparity to gain a holistic understanding of the pterosaur macroevolution. The first two parameters are important in quantitative analyses of macroevolution, but they have been rarely used in previous pterosaur studies.
View Article and Find Full Text PDFMolecular studies suggest that the origin of jawed vertebrates was no later than the Late Ordovician period (around 450 million years ago (Ma)). Together with disarticulated micro-remains of putative chondrichthyans from the Ordovician and early Silurian period, these analyses suggest an evolutionary proliferation of jawed vertebrates before, and immediately after, the end-Ordovician mass extinction. However, until now, the earliest complete fossils of jawed fishes for which a detailed reconstruction of their morphology was possible came from late Silurian assemblages (about 425 Ma).
View Article and Find Full Text PDFInnovations relating to the consumption of hard prey are implicated in ecological shifts in marine ecosystems as early as the mid-Paleozoic. Lungfishes represent the first and longest-ranging lineage of durophagous vertebrates, but how and when the various feeding specializations of this group arose remain unclear. Two exceptionally preserved fossils of the Early Devonian lobe-finned fish Youngolepis reveal the origin of the specialized lungfish feeding mechanism.
View Article and Find Full Text PDFThe end-Permian mass extinction (EPME) led to a severe terrestrial ecosystem collapse. However, the ecological response of insects-the most diverse group of organisms on Earth-to the EPME remains poorly understood. Here, we analyse beetle evolutionary history based on taxonomic diversity, morphological disparity, phylogeny, and ecological shifts from the Early Permian to Middle Triassic, using a comprehensive new dataset.
View Article and Find Full Text PDFRecent studies demonstrate that many avialan features evolved incrementally prior to the origin of the group, but the presence of some of these features, such as bird-like brooding behaviours, remains contentious in non-avialan dinosaurs. Here we report the first non-avialan dinosaur fossil known to preserve an adult skeleton atop an egg clutch that contains embryonic remains. The preserved positional relationship of the adult to the clutch, coupled with the advanced growth stages of the embryos and their high estimated incubation temperatures, provides strong support for the brooding hypothesis.
View Article and Find Full Text PDFReconstructing the history of biodiversity has been hindered by often-separate analyses of stem and crown groups of the clades in question that are not easily understood within the same unified evolutionary framework. Here, we investigate the evolutionary history of birds by analyzing three supertrees that combine published phylogenies of both stem and crown birds. Our analyses reveal three distinct large-scale increases in the diversification rate across bird evolutionary history.
View Article and Find Full Text PDFTetanurae is a special group of theropod dinosaurs that originated by the late Early Jurassic. It includes several early-diverging groups of generally large-bodied predators (megalosauroids, allosauroids, tyrannosauroid coelurosaurs) as well as morphologically disparate small-bodied coelurosaurs, including birds. Aspects of the evolutionary history of tetanurans remain contested, including the topology of their deep phylogenetic divergences (among Megalosauroidea, Allosauroidea and Coelurosauria).
View Article and Find Full Text PDFThe bone-beds of the Upper Cretaceous Wangshi Group in Zhucheng, Shandong, China are rich in fossil remains of the gigantic hadrosaurid Shantungosaurus. Here we report a new oviraptorosaur, Anomalipes zhaoi gen. et sp.
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