Nannostratigraphy and investigation of sedimentation conditions of the lower boundary and the upper boundary of the Aitamir Formation in the east and west Kopet Dagh,northeast of Iran

By attention to the stratigraphic value of calcareous nannoplanktons for the age determination of sedimentary beds, for the first time Late Cretaceous calcareous nannofossil taxa, their distributions and relative abundances were recorded from the lower and the upper boundary of Aitamir Formation located in northeast Iran. In the present study, biostratigraphy and paleoecological conditions were reconstructed. The Aitamir Formation comprises glauconitic sandstones and olive-green shales. In this work, samples were prepared with smear slides, and nannofossils of these boundaries are listed and figured. They were photographed under a light microscope. Based on nannoplanktons and as a result of biostratigraphic studies, the age of the lower boundary of the Aitamir Formation in the east Kopet Dagh is Early/Middle Turonian, the age of the lower boundary in the west Kopet Dagh is Late Turonian/Early Coniacian, the age of the upper boundary of the Aitamir Formation in the east Kopet Dagh is Late Santonian, and the age of the upper boundary of this Formation in the west Kopet Dagh is Early Campanian. Based on paleoecological interpretation, the Aitamir Formation was deposited in a shallow marine environment, at relatively low latitude. A deepening trend of the sedimentary basin is recognized passing from Aitamir Formation to the overlying Abderaz Formation while in the lower boundary from Sanganeh to Aitamir Formation depth decreased.     

Nannostratigraphy and palaeoecology of uppermost Mozduran Formation in the Kopeh-Dagh range (NE Iran)

The Mozduran Formation includes light-coloured, thick-bedded to massive limestone and porous dolomitic limestone and dolomite. In this study, 13 samples from the uppermost Mozduran Formation were taken from two localities and examined for calcareous nannofossils. A total of 19 species and 12 genera were identified in the Mozduran section and19 species and 13 genera for the Taherabad section. Based on these assemblages, the uppermost Mozduran Formation is assignable to Sissingh's (1977) biozone CC1 (Early Berriasian) at the Mozduran section and to biozone CC3 (Late Valanginian) at the Taherabad section. Thus, the formation is younger from east to west across the basin.     

A New Species of Huaxiapterus （Pterosauria： Tapejaridae） from the Early Cretaceous of Western Liaoning, China

A new species of Huaxiapterus： H. benxiensis sp. nov. is erected based on the new specimen. The diagnostic characters of Huaxiapterus benxiensis are well-developed premaxillary crest and parietal spine, the crest and spine parallel and extending posterodorsally, and a shallow groove present on the dorsal surface of the anterior portion of the mandibular symphysis. The different skull morphologies of Chinese tapejarid pterosaurs indicate that they are much more diverse than the previous thought.     

弓长岭太古代条带状硅铁建造中长英质变质岩的原岩恢复及地层学意义

弓长岭太古代条带状硅铁建造中的长英质变质岩为该地层的标志层(K和K_S层)。原岩恢复表明二矿区黑云母石英钠长变粒岩(K层)为含火山灰的中酸性火山熔岩;而岭东区的石榴云母石英片岩(K_S层)为含火山灰的泥砂质沉积岩,二者不能对比。据此,本文补充和完善了该区地层剖面。它表明弓长岭硅铁建造生成于大陆边缘的陆棚浅海环境,其铁矿层赋存于一海进层序的中上部。该建造的沉积岩组合特征与绿岩带不同,而与典型的高级区表壳岩组合类似。     

A Review of the Tetrapod Track Record in China,with Special Reference to Type Ichnospecies:Implications for Ichnotaxonomy and Paleobiology

<正>"Splitting" and "lumping" are perpetual problems in vertebrate,especially dinosaur, ichnotaxonomy.Chinese dinosaur ichnotaxonomy,which began in 1940,provides a series of interesting case studies,highlighting the dual problems of historical and dubious ichnotaxonomy. Chinese Mesozoic tetrapod track types have been placed into 63 ichnospecies(one Triassic,28 Jurassic,and 34 Cretaceous),exclusive of other,non-type ichnospecies or ichnotaxa identified from China.Fifty-two(～83%) of these 63 tetrapod ichnospecies were placed in monospecific ichnogenera. At the ichnogenus level,we prune—either by recognizing nomina dubia or by synonymy—17 from the list of 53 dinosaurian ichnogenera(a 32%reduction),leaving 36 ichnotaxa that we consider valid. Most of the cuts affect Jurassic theropod ichnotaxa,which are reduced from 23 to only nine because most ichnogenera are subjective junior synonyms of Grallator and Eubrontes.Fewer Chinese Cretaceous ichnotaxa(only six of 21 ichnogenera) are obvious nomina dubia or subjective synonyms, suggesting greater east Asian endemism during this time.Because ichnospecies differences are subtle, we provisionally retain ichnospecies as valid pending detailed comparative analyses of congeneric ichnospecies.This synthesis is long overdue and is necessary to address problems of historical and provincial ichnotaxonomy,which severely hamper comparisons of tetrapod ichnofaunas in space and time.     

四川盆地北缘发现白垩纪恐龙足迹化石

2020年10月,笔者在四川盆地北缘的四川省通江县下白垩统苍溪组粉砂岩层面之上,新发现5个恐龙足迹化石,其形态均与经典的兽脚类足迹Eubrontes相似（如双足动物所留,足迹宽,功能性三趾型,较短的第Ⅲ趾）。该发现表明,Eubrontes这种中大型的兽脚类足迹广泛分布在四川盆地的下白垩统。该发现对于四川盆地北缘的古气候、古地理和地层对比都具有重要意义。     

北京延庆千家店地区土城子组恐龙足迹点沉积环境

北京延庆千家店地区晚侏罗世土城子组化石稀少,而新发现的恐龙足迹是北京恐龙存活过的重要证据,研究其沉积环境对恢复当时恐龙动物群的生活环境具有十分重要的意义。研究区恐龙足迹主要包括兽脚类、蜥脚类和可能的鸟脚类足迹。运用地层学、岩石学、古生物学和沉积学方法,通过地层剖面、岩石薄片、足迹分布、沉积构造及详细的粒度分布特征,综合得出千家店地区土城子组三段恐龙足迹点的沉积环境,认为当时的沉积环境为含火山碎屑的浅湖沉积,恐龙足迹的赋存层位为湖滨环境。     

贵州毕节侏罗系恐龙足迹新发现

2019—2020年,笔者在贵州省毕节市大方县元宝箐与七星关区叶家田发现了2个恐龙足迹点。元宝箐的足迹产于自流井组马鞍山段底部,类型为基干鸟臀类的异样龙足迹和中型蜥脚类足迹,其中,异样龙足迹为四川盆地下侏罗统首次记录该类足迹。叶家田的足迹产于上沙溪庙组,类型为大型蜥脚类足迹,其造迹者可能与该组繁盛的马门溪龙、峨眉龙等大型蜥脚类有潜在的关联性。该发现对更好地理解四川盆地南缘侏罗纪早中期古脊椎动物群提供了帮助。     

恐龙相关数据库的发展现状与数据驱动下的研究实例剖析

恐龙是知名度最高的古生物类群之一,在中生代处于陆地优势生态位,这对研究地球生命演化具有重要意义。近年来,随着恐龙学数据的激增以及统计分析手段的进步,全球涌现出多种类型的恐龙相关数据库。文章对这些数据库进行了调研和分析,并将其分成纯科普型、特定目标型和全面型三种类型。但严格来说,它们都不是真正意义上的系统、全面的恐龙学数据库,分别存在着数据涵盖不全、结构体系不合理、缺乏长期可持续性等缺点。因此,在深时数字地球(Deeptime Digital Earth,简称DDE)大科学计划的助力下,搭建起兼具科学性与科普性的恐龙学数据库,不仅能够促进深时地球生命演化的研究,还能提升大众对DDE的了解。     

New Early Cretaceous Pterosaur-Bird Track Assemblage from Xinjiang, China: Palaeoethology and Palaeoenvironment

A pterosaur-bird track assemblage from a sandstone-siltstone-mudstone sequence of the Lower Cretaceous Tugulu Group of Xinjiang comprises the first pterosaur track record from this province and the largest specimen thus far known from China.The pterosaur tracks are assigned to the ichnogenus Pteraichnus based on the triangular overall-shape,the four elongate digit traces and the robust manual digit trace Ⅲ.Supposed trackmakers were dsungaripterid pterodactyloids whose skeletal remains are well known from the Tugulu Group.The bird tracks that occur on the same surface,are those of typical shorebirds,known from different other localities in southeast Asia.The congruence with Koreanaornis dodsoni described from the same stratigraphic level justifies an assignment to this ichnospecies.This is a further evidence of the co-occurrence of pterosaurs and birds in a typical iakeshore environment with possible seasonal alteration of water supply and aerial exposure indicated by wave ripples,mudcracks and repeated cycles of coarse to fine sediment.Pterosaurs and birds frequented the shoreline and may have fed also on the numerous invertebrates such as the Scoyenia tracemaker that left abundant burrows.