"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.
Martin G.LOCKLEYLI JianjunLI RihuiMasaki MATSUKAWAJerald D.HARRISXING Lida
Timing of uplift of the Tibetan Plateau is a fundamental work to understand global climatic change and mountain\|building mechanism. Because most of the evidence comes from the Himalaya\|South Tibet, the northern margin of the Plateau may hold the key to unravel a whole view of the Plateau uplift history, in which basin sediments are the most important part because they have continuously recorded the history of pure surface uplift in related mountains. In the whole foredeep bordered by the North Marginal Thrust (Kunlun—Altun—Qilian—Longmen Trusts) along the northern and eastern Tibetan Plateau, thick Cenozoic stratigraphy is widely distributed and records the whole history of the Plateau uplift process. It can be lithologically divided in three large units from top to bottom: light colored sediments, boulder conglomerate and red bed. The red bed is mostly fine sediments of lacustrine and/or fluviolacustrine origins and the boulder conglomerate has been long thought as evidence of rapid uplift of the Tibetan Plateau. The light colored sediments are mostly eolian and/or fluviolacustrine deposits or desert\|gobi sediments. Thus, to date the boulder conglomerate holds the key to unravel the Plateau uplift. We chose the Linxia Basin in the northeastern Tibetan Plateau and Jiuquan Basin in the northern Qilian Mountains as two pilot controlling sites to reconstruct the history of uplift process of the Tibetan Plate au and its accompanied climatic change and to see if a coupling process would ex ist between the uplift of the Plateau and Asian monsoon system.
Fang Xiaomin, Li Jijun, Zhao Zhijun, Yan Maodu, Ma Yuzhen
The magnetostratigraphic sampling was carried out respectively in the inside part (14 cm away from the section surface along the bed) and outside part (5 cm away from the section surface along the bed) with no interval at the same bed (Bed 27) which the paleobiology boundary (PBB) of A and D sections lies in of Meishan, Changxing. This research shows that the deep samples suffered slighter secondary magnetization than the shallow ones did and in comparison with D section ’s samples, the samples of A section sustained slighter secondary magnetization. On the bases of the data, the secondary magnetization influence of which is relatively weak, this paper obtains the conclusion that the bed, in which the paleobiology boundary lies, lies within the reverse polarity subzone.
Zhu Yanming Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074 Morinaga Hayao Department of Geology, Faculty of Sciences, Himeji Institute of Technology, Himeji 672 22, Japan