贵州盘县中三叠世混鱼龙类研究进展及"Mixosaurus yangjuanensis Liu and Yin,2008"的疑问和相关问题

盘县新民乡羊圈村及其邻区关岭组上段产出两种混鱼龙:Mixosaurus panxianensis Jiang et al.,2006和Phalarodon cf.P.fraasi Merriam,1910.含混鱼龙类化石层时代应为中三叠世安尼期Pelsonian亚期."Mixosaurus yangjuanensis Liu and Yin,2008"命名所依据的正模标本无关键的头骨特征,选取的头后骨骼做鉴定特征对混鱼龙类种一级分类无意义,鉴定特征所依据的基本骨块存在鉴定错误;"Mixosaurus maotaiensis"的厘定应无效;盘县动物群中无Mixosaurus cornalianus出现.     

CCR8 is not essential for the development of inflammation in a mouse model of allergic airway disease

Chemokine receptors play an important role in the trafficking of various immune cell types to sites of inflammation. Several chemokine receptors are differentially expressed in Th1 and Th2 effector populations. Th2 cells selectively express CCR3, CCR4, and CCR8, which could direct their trafficking to sites of allergic inflammation. Additionally, increased expression of the CCR8 ligand, TCA-3, has been detected in affected lungs in a mouse model of asthma. In this study, CCR8-deficient mice were generated to address the biological role of CCR8 in a model of allergic airway disease. Using two different protocols of allergen challenge, we demonstrate that absence of CCR8 does not affect the development of pulmonary eosinophilia and Th2 cytokine responses. In addition, administration of anti-TCA-3-neutralizing Ab during allergen sensitization and rechallenge failed to inhibit airway allergic inflammation. These results suggest that CCR8 does not play an essential role in the pathogenesis of inflammation in this mouse model of allergic airway disease.     

The sea as deathtrap: comment on a paper by miller and wiens

Miller & Wiens (2017) claim that low marine as compared with terrestrial diversity results from more frequent extinctions and insufficient time for diversification in marine clades. Their data on marine amniotes are unrepresentative of marine diversity, their analysis of clade dynamics is flawed, and they ignore previously proposed explanations for the diversity difference.     

New species of Thylacocephala (Arthropoda) from the Spathian (Lower Triassic) of Chaohu,Anhui Province of China

We describe a new species of Thylacocephala, Ankitokazocaris chaohuensis sp. nov., from the Upper Spathian (Early Triassic) of Chaohu, Anhui Province, China. It is diagnosed by its unique outline of the carapace, small size, and the narrow and asymmetrical anterior notch. Fine preservation reveals at least 14 posterior appendages, traces of gills and raptorial appendages, and remains of trunk segments and muscles in Ankitokazocaris for the first time. This is the first report of Thylacocephala from the Early Triassic of China, confirming the wide distribution of this group in the Tethys. The new species is closer to the type species of Ankitokazocaris, which is stratigraphically somewhat older, than to a recently described almost coeval species from Japan.     

The Enigmatic Marine Reptile Nanchangosaurus from the Lower Triassic of Hubei,China and the Phylogenetic Affinities of Hupehsuchia

The study of the holotype and of a new specimen of Nanchangosaurus suni (Reptilia; Diapsida; Hupehsuchia) revealed a suite of hitherto unrecognized characters. For example, Nanchangosaurus has bipartite neural spines and its vertebral count is nearly identical to that of Hupehsuchus. It differs from the latter in having poorly developed forelimbs despite the advanced ossification in the rest of the skeleton. Other differences all pertain to hupehsuchian plesiomorphies retained in Nanchangosaurus, such as low neural spines. The relationship of Hupehsuchia within Diapsida was analyzed based on a data matrix containing 41 taxa coded for 213 characters, of which 18 were identified as aquatic adaptations from functional inferences. These aquatic adaptations may be vulnerable to the argumentation of character homology because expectation for homoplasy is high. There is an apparent incongruence between phylogenetic signals from aquatic adaptations and the rest of the data, with aquatic adaptations favoring all marine reptiles but Helveticosaurus to form a super-clade. However, this super-clade does not obtain when aquatic adaptations were deleted, whereas individual marine reptile clades are all derived without them. We examined all possible combinations of the 18 aquatic adaptations (n = 262143) and found that four lineages of marine reptiles are recognized almost regardless of which of these features were included in the analysis: Hupehsuchia-Ichthyopterygia clade, Sauropterygia-Saurosphargidae clade, Thalattosauria, and Helveticosaurus. The interrelationships among these four depended on the combination of aquatic adaptations to be included, i.e., assumed to be homologous a priori by bypassing character argumentation. Hupehsuchia always appeared as the sister taxon of Ichthyopterygia.     

Adult sex ratio,sexual dimorphism and sexual selection in a Mesozoic reptile

The evolutionary history of sexual selection in the geologic past is poorly documented based on quantification, largely because of difficulty in sexing fossil specimens. Even such essential ecological parameters as adult sex ratio (ASR) and sexual size dimorphism (SSD) are rarely quantified, despite their implications for sexual selection. To enable their estimation, we propose a method for unbiased sex identification based on sexual shape dimorphism, using size-independent principal components of phenotypic data. We applied the method to test sexual selection in Keichousaurus hui, a Middle Triassic (about 237 Ma) sauropterygian with an unusually large sample size for a fossil reptile. Keichousaurus hui exhibited SSD biased towards males, as in the majority of extant reptiles, to a minor degree (sexual dimorphism index −0.087). The ASR is about 60% females, suggesting higher mortality of males over females. Both values support sexual selection of males in this species. The method may be applied to other fossil species. We also used the Gompertz allometric equation to study the sexual shape dimorphism of K. hui and found that two sexes had largely homogeneous phenotypes at birth except in the humeral width, contrary to previous suggestions derived from the standard allometric equation.     

Phenylalanine derivatives as GPR142 agonists for the treatment of Type II diabetes

GPR142 is a novel GPCR that is predominantly expressed in pancreatic β-cells. GPR142 agonists potentiate glucose-dependent insulin secretion, and therefore can reduce the risk of hypoglycemia. Optimization of our lead pyridinone-phenylalanine series led to a proof-of-concept compound 22, which showed in vivo efficacy in mice with dose-dependent increase in insulin secretion and a decrease in glucose levels.