Chancelloriid sclerites from the lowermost Cambrian of North China and discussion of sclerite taxonomy

Chancelloriid sclerites from the lowermost Cambrian Xinji Formation (Series 2, Stage 3), southern margin of the North China platform, are systematically described. Thousands of isolated sclerites from three sections are assigned to three genera and four species, including Chancelloria cf. eros, Allonnia tripodophora, Archiasterella pentactina, and Ar. tetraspina. To accurately document the taxonomic significance of the sclerite structure, modified formulas (m+nC, m+nA, and m+0) are put forward to represent the full series and variation of sclerite forms. Based on the sclerite construction, statistical analysis on the proportions of different sclerite forms in the rock samples and the composition of sclerites in previously described chancelloriid scleritomes, a new scheme for identification and classification of isolated sclerites reconciled within the framework of the complete scleritome, is proposed.     

Dinosaur footprints from the Sao Khua Formation (Early Cretaceous) of Phu Kao National Park,Northeast Thailand

The first documented dinosaur footprints from Southeast Asia were theropod footprints found in Thailand at Phu Luang Wildlife Sanctuary. Since then, Mesozoic vertebrate footprints have been discovered in twelve different localities in Thailand. In 2000, dinosaur footprints were found in Phu Kao National Park in Northeastern Thailand, however, they have never been studied in detail. The following study presents the first map, the complete measurements, the geology, and stratigraphy of the site and surrounding area. The study discusses the nature of the trackmaker and the digitigrade character of the footprints. This discovery represents the first documented occurrence of dinosaur footprints inside the Early Cretaceous Sao Khua Formation from Thailand.     

Trilobites from the Silurian “Lower Red Beds” of Wuhan,South China: stratigraphic and paleogeographic implications

The age of the Silurian “Lower Red Beds” (LRBs), which occur widely in South China, has long been controversial because of the scarcity of index fossils. Here, we report a fauna with abundant trilobites from the LRBs in Wuhan, Middle Yangtze region, consisting of Aulacopleura (Paraaulacopleura) pijiazhaiensis, ‘Encrinuroides’ yichangensis, Gaotania hubeiensis, Hyrokybe gaotanensis, Japonoscutellum yichangense, Latiproetus latilimbatus, and Ptilillaenus lojopingensis. These trilobites are common in the Leijiatun, upper Xiangshuyuan, Shihniulan, and Lojoping formations in the Upper Yangtze region, and belong to the middle to upper Aeronian Ptilillaenus or ‘Encrinuroides’–Ptilillaenus–Latiproetus assemblages. The discovery of this trilobite assemblage suggests that the LRBs are probably partly of middle–late Aeronian age in the Middle Yangtze region. Thus, the lower boundary of the LRBs is likely diachronous in the Yangtze region, ranging from the middle–late Aeronian to the early Telychian. The discovery of the Ptilillaenus assemblage in the Wuhan LRBs expands the paleogeographic distribution of this assemblage and provides evidence of deeper depositional environment of the LRBs in the study area versus shallow waters in other areas of the Yangtze region.     

AN ALMOST COMPLETE JUVENILE SPECIMEN OF THE CHELONIID TURTLE CTENOCHELYS STENOPORUS (HAY, 1905) FROM THE UPPER CRETACEOUS NIOBRARA FORMATION OF KANSAS,USA

Abstract: A new, unusually well‐preserved juvenile specimen of Ctenochelys stenoporus from the Niobrara Formation is described. The skull has come apart at its sutures and all bones of the braincase and ear region are preserved three‐dimensionally. This allows a detailed reconstruction of the important brain structures of a basal juvenile cheloniid turtle. It is compared with adult Ctenochelys specimens, and the major ontogenetic changes in the skull and postcranial skeleton are described. Furthermore, the specimen is compared with other fossil and extant cheloniids with well‐known braincases and the differences between basal and advanced cheloniids turtles are specified.     

Palaeoskapha sichuanensis gen. et sp. nov. (Menispermaceae) from the Eocene Relu Formation in western Sichuan, West China

Palaeoskapha sichuanensis gen. et sp. nov. of Menispermaceae is described here for the first time based on a well preserved fossil fruit. The specimen was found in the Relu Formation of western Sichuan, West China. The specimen, straight, boat-shaped endocarp with large ventral condyle, clearly belongs to the tribe Tinosporeae. The wide aperture of the double condyle, combined with a whole shape not deeply invaginated, indicates a genus different from what was already known to science for this tribe. This fossil widens the distribution of the tribe during Eocene from North America and Europe to Asia, where it was formerly unknown.     

长城系串岭沟组球形疑源类的超微结构

中国天津蓟县古元古代长城系串岭沟组页岩中保存有丰富的球形疑源类化石。本文对这一微化石组合进行了光学生物显微镜、扫描电子显微镜和透射电子显微镜的对比研究。研究发现,以往一些被作为属征的结构,如,膜壳壁的厚薄、网状纹饰和褶皱等,很可能是生物降解和成岩作用的结果。因此,以前描述的10个不同属的球形疑源类的系统分类有待于重新研究和厘定,也许把它们都归入光面球藻属Leiosphaeridia更合适。在透射电子显微镜下观察,球形疑源类壁的超微结构一致,都分为三层,中间层为电子密度低的较厚层,内层和外层为电子密度高的较薄层。这一特征与现生绿藻非常类似而与蓝藻包鞘明显不同,表明串岭沟组的球形疑源类可能与绿藻有较近的亲缘关系。     

新疆玛纳斯河畔红沟剖面西山窑组和头屯河组孢粉组合及地层意义

本文系统地研究了新疆玛纳斯河红沟剖面西山窑组和头屯河组孢粉化石,共计51属108种。根据孢粉属种组成及其含量的变化,自下而上分为2套组合:1.Cyathidites-Neoraistrisckia-Disacciatrileti(CND)组合,2.Cyathidites-Disacciatrileti-Classopollis(CDC)组合。依据组合中一些重要分子的地质时限讨论及其与相关组合的对比,将“CND”组合的地质时代归为中侏罗世早期,“CDC”组合归为中侏罗世晚期。在综合分析和对比新疆一些地区中侏罗世孢粉组合的基础上,自下而上建立了2个孢粉组合带,即:Cyathidites-Neoraistrisckia-Quadraeculina-Cycadopites(CNQC)组合带,Cyathidites-Quadraeculina-Classopollis(CQC)组合带。     

A new species of basal rhynchosaur (Diapsida: Archosauromorpha) from the early Middle Triassic of South Africa,and the early evolution of Rhynchosauria

Rhynchosauria was an important clade of herbivorous archosauromorph reptiles during the Triassic, with a worldwide distribution. We describe a new genus and species of early rhynchosaur, E ohyosaurus wolvaardti gen. et sp. nov. , from the early Middle Triassic (early Anisian) Cynognathus Assemblage Zone (Subzone B) of the Karoo Supergroup, South Africa. Eohyosaurus wolvaardti is known from a single skull, and is recovered as the sister taxon of Rhynchosauridae in a new phylogenetic analysis. Cynognathus Subzone B has previously yielded the stratigraphically oldest well‐understood rhynchosaur species, Mesosuchus browni and Howesia browni. Eohyosaurus wolvaardti increases the rhynchosaur diversity within this stratigraphical horizon to three species. Intriguingly, all currently confirmed rhynchosaur occurrences from the Early Triassic to earliest Middle Triassic are from South Africa. This may suggest a relatively restricted palaeogeographical distribution for early rhynchosaurs, followed by a global dispersal of rhynchosaurids during the Middle Triassic. © 2015 The Linnean Society of London     

Paleoenvironmental reconstruction of an Albian plant community from the Ariño bonebed layer (Iberian Chain,NE Spain)

The AR-1 layer, corresponding to the Escucha Formation (Lower Cretaceous) in the Santa Maria Mine of Ariño, has supplied rich and well-preserved macrofloral and palynological assemblages showing interesting data about both taphonomic and environmental conditions. This single layer is located in the Oliete Sub-Basin from the Maestrazgo Basin in northeastern Spain, and it represents one of the most outstanding single layer fossil sites in the world. This site shows abundant and diverse fauna containing exquisitely preserved vertebrate and invertebrate fossils (dinosaur bones, turtles, crocodiles, fishes, molluscs and ostracods) and also plant remains of Albian age. The assemblage is especially significant for dinosaur phylogenetic analysis. The sedimentary environment corresponds to a freshwater swamp plain with sporadic marine inputs within a deltaic–estuarine system under subtropical–tropical climate.     

Singular taphonomic record of a wildfire event from middle Albian deposits of Escucha Formation in northeastern of Spain

A fossil plant assemblage composed of a great amount of macro, meso and microscopical charcoalifed remains occur in a single layer in Albian deposits of the Escucha Formation in northeastern Spain. This assemblage consists fundamentally of fragments of pinnae and pinnules corresponding to the Matoniaceous ferns Weichselia reticulata and Phlebopteris dunkeri also with some gymnosperm wood remains. The features of both the fossil plants and the deposit itself indicate accurate paleoenvironmental conditions related to the action of wildfires over the vegetation growing in freshwater swamp plains during Albian in Southwestern Eurasia.