Abstract:
In this year, the authors collected numerous the Ordovician pallaeofishes fossils from the Qiaerbake Formation (i.e.The Tumuxiuke Formation) in Bachu Couty, Xinjiang. China. According to possessing a pair of orbite opening and bones structure on the head dermal, this fossils belong to the Agnatha and include the Bachuiaspida (Subclass nov.), Bachuiaspidida (Order nov.), Palaeogaleaspidida(Order nov.), Bachuiaspididae (Family nov.), Palaeogaleaspidida (Family nov.) and four new genera, new species: Bachuiaspis elegans, Brevicaraspis yijianfangensis, Palaeogaleaspis platyrostrastus and Cyclocephalaspis haoae. The age of present fossils is determined in the Late Ordovician by the conodonts zone-Baltoniodus alobatus. These are abundant fossils as complete individual bodies presented. In this paper, this agnathans fossils group is named Bachuiaspis elegans- Palaeogaleaspis platyrostrastus fauna by the authors. At present, the researches of the agnathans fossils are preliminary, the biology, biostratigraphy, sedimentary-environment and the division of the palaeobiogeographic regions would be gradually and deeply. This agnathans fossils fauna should be of important scientific values for the origins, evolutionary of the vertebrates and the vertebrate biogeography, division of the palaeotectonic region, which would be a conclusive record of biological evidence for vertebrate in China and a special vertebrate fauna of China in the world in the early Late Ordovician.