Crocodylomorphs and choristoderes were semi-aquatic predators in the Mesozoic fresh-water ecosystem, sharing similar skull shapes specialized for consuming fish or small vertebrates. The two clades have rarely been documented at the same fossil site, leading to a hypothesis that competition prevailed between crocodylomorphs and choristoderes. Here a new crocodyliform is reported from the Jehol Biota in Liaoning, Northeast China. The specimen (IVPP V18004) was discovered from the Early Cretaceous Yixian Formation from which hundreds of choristodere specimens have been described. Morphological comparisons suggest the new specimen (Crocodyliformes cf. Shantungosuchus) was a new crocodyliform resembling Shantungosuchus, another Early Cretaceous genus distributed in northeast China. The tibia and fibula of the new specimen are longer than the femur – a rare proportion that has been associated with terrestrial habit among crocodylomorphs. To test whether the new crocodyliform was a terrestrial species partitioning resources with semi-aquatic choristoderes, hindlimb proportions were compared among extant and extinct species, including terrestrial crocodylomorphs, semi-aquatic crocodylomorphs, and semi-aquatic choristoderes. The hindlimb (full length set as 100%) was divided into three articulating segments: the femur, tibia, and pes. Relative proportions of the three segments were measured and plotted on a ternary graph. In the morphospace composed with the ternary graph, the new specimen clustered with other terrestrial crocodylomorphs including Protosuchus and Araripesuchus. Choristoderes clustered with extant crocodylomorphs that were also semi-aquatic. The results showed hindlimb proportions indicate habitat adaptations in crocodylomorphs. The new specimen was terrestrial, occupying a different niche from semi-aquatic choristoderes. The Jehol Biota provides the first record of crocodylomorphs partitioning resources with choristoderes at the same site, which sheds light on the interactions of predators in the Mesozoic terrestrial environments.

Burmese amber, from Myanmar, has yielded a highly diverse tropical fossil biota, which provides invaluable insights into the Cretaceous forest ecosystems. However, its exact age remains controversial, hampering reliable paleobiologic interpretations. Here, we initially constrain the age of amber from northern Myanmar based on high-precision CA-ID-TIMS U-Pb geochronology. Our results reveal an Albian to early Cenomanian age for the (northern) Burmese amber (~112 Ma for Khamti amber and ~100-98.8 Ma for Kachin amber), which coincides with the onset of magmatism of the Wuntho-Popa Arc. Burmese amber (senso lato) appears to have a protracted depositional history, ranging at least from early Albian to late Campanian. The new geochronology elucidates the origin and early evolution of some important biologic elements and animal behaviours recorded in Burmese amber.

Paraves, as one of the major lineages of the coelurosaurian dinosaurs, is traditionally known to comprise Dromaeosauridae, Troodontidae and Avialae. Mesozoic paravians are among the best studied dinosaur groups as they represent the transitional stage from the basal theropod dinosaurs to modern birds. Many new fossil taxa of the paravian subgroups were reported recently, which dramatically increased the diversity of this clade and improved our understanding of the biology and ecology of Mesozoic paravians. This study supplements the current paravian morphological data matrix by incorporating recently reported paravian taxa/specimens with updated characters, and performs the phylogenetic analyses with both the maximum parsimony criterion and the Bayesian inference. New ecomorphological data of the mandibles and the postcranial skeleton have been acquired by traditional examination, CT scanning and Micro X-ray fluorescence scanning on both old and new specimens, which provides a valuable opportunity to review the evolutionary history of the Mesozoic paravians as well as their roles in the origin of birds. Ecomorphological analyses with more anatomical details from the Late Jurassic and Early Cretaceous paravians of the Yanliao Biota and the Jehol Biota indicate the earliest paravian evolution with higher complexity than previously expected. High disparities of the body size and other osteological features have also been detected in Mesozoic paravians, possibly indicating the complexity of the ecomorphologcal adaptations during the paravian radiation. These new findings provide us a chance to investigate the details on the dietary and the locomotor changes through the dinosaur-bird transition.

The Procercopodae, widely recognized as the most ancient family of the Cercopoidea and a transitional unit to modern group, can be traced from the Early Jurassic to mid-Cretaceous. During the past 30 years, abundant and well-preserved Mesozoic procercopids, belonging to 44 species in 11 genera have been discovered and described in Kyrgyzstan, Germany, Russia, China, Korea and Burma. However, no specimen of Cretaceous procercopids has been reported from UK.A new genus and species of Procercopidae, Valdicopis Li, Chen and Jarzembowski, gen. nov. and Valdicopis tonyi Li, Chen and Jarzembowski, gen. et sp. nov. are described from the Lower Cretaceous of southern England. V. tonyi represents the first fossil record of Procercopidae from England and the first procercopid from the Cretaceous of Europe, providing new morphological information and extending the biogeographic distribution of the Procercopidae. It is different from other genera in having a slender tegmen with three vertical white bands; Pc + CP extremely long and thick, almost submerged to terminal CuA₂; RA and RP unbranch; MP two-branched; crossvein rp-mp distal to crossvein ir; crossvein imp absent; CuA₁ fused with MP₃₊₄; crossvein cua-cup connecting CuA; vein R, MP, and CuA leaving basal cell at commom point.

Eastern China was in a relatively active period of tectonic activity during the Late Mesozoic, which was also an important period for the formation of energy and mineral, so it had always been a research hotpot in the academic circles at home and abroad. The Ri-Qing-Wei Basin, a large rifting basin, was formed in the east coastal area of Shandong in the late Mesozoic, and its provenance, sedimentary environment and tectonic setting are the focus of controversy. In this study, thin section identification and geochemical test were conducted on the mixed carbonate and siliciclastic sediments of Laiyang Group in Shiziyuan area of the Ri-Qing-Wei Basin. The results of thin section identification shows that the lithologies are mixed rocks formed by microcrystalline-micritic carbonatites and argillaceous siltstones. The index of composition variability (ICV) suggests the mixed sediments are immature and sediment in first cycle. The K₂O/Al₂O₃ and Th/U rations indicate weak weathering condition. The geochemical results indicate the sedimentary source rocks are felsic igneous rocks. Major- and trace-based tectonic setting discriminant diagrams indicate the source rocks were formed in continental island arc and active continental margin. Geochemical indexes and bivariate plot based on major and trace elements contents show that the Laiyang Group was mainly deposited in arid conditions and the sedimentary environment was reducing marine environment.