地质论评2017，Vol.63Issue(6)：1602-1612,11.DOI:10.16509/j.georeview.2017.06.014
新疆巴楚地区中—晚奥陶世古脊椎动物系统生物学研究
The Systematic Biological Study on Middle—Late Ordovician Bachuiaspids (Agnatha) Fauna from Bachu County, Xinjiang, China
摘要
Abstract
In recent years,the authors discovered numerous the Late Ordovician agnathan fossils in the Yijiangfang section,Bachu County,Xinjiang.The occurrence of these fossils is of great significance for understanding the evolution of the early vertebrates from the Ordovician to the Silurian—Devonian.This paper is focused on the systematic biological description of some fossils,other material will be described and studied in the future.Subclass:Bachuiaspida Wang & Guo 2011 Diagnosis:Single carapace cover the head and trunk shield and turn to ventral aspect form a ventral rim.Head shield shuttle,triangle and round in shape.Carapace strong and compact,face layer compose of fine and small tuberculars.No median dorsal opening.Pineal body very small,orbits behind pineal.The posterior median process distributed in middle of posterior margin.Soc,ioc,ldc sensory canals in distribution.Six paired of branchial fossae and independent external branchial openings in branchial region.No ventral,dorsal,and tail fins.Order Bachuiaspidida Wang & Guo 2011 Diagnosis:Single carapace covers head and trunk,and turn to ventral aspect forming ventral rim.Head shield shuttle and triangle in shape.Carapace composed of fine and small tuberculars.Rostrum margin process anteriorly.No median dorsal opening.Pineal body and orbits small.Posterior margin process posterioly or concave in meddle slightly.The structure (Soc,ioc,ldc.) distributes in the armour.Possess six paired of independent external branchial openings.No dorsal,ventral and tail fins.Family Bachuiaspidae Wang & Guo 2011 Diagnosis:see Order diagnosis.Genus Bachuiaspis Wang & Guo 2011 Diagnosis:Head shield smaller,single carapace cover head and trunk shield,and turn ventral aspect forming ventral rim.Head shield longer,shuttle in shape,width/length-1/2.Rostrum margin process anterior,lateral margin curve laterally.Posterior margin possess posterior median process.No median dorsal opening.Pineal body 1/6 distance from anterior margin of head shield.The structure (Soc,ioc,ldc.) distribution in head shield.Six paired of external branchial openings in characteristic of ventral aspect.No ventral,dorsal,tail fins.Type species Bachuiaspis elegans Wang & Gou 2011Holotype:a complete head shield,specimen number:5-27-4.Other material:5-27-13,5-27-6,5-28-5,7-19-2.Locality and horizon:Qaerbake Formation,Late Ordovician,Yijianfang,Bachu County,Xinjiang.Description:The holotype of fossil is a median head shield preserved,its posterior part is lacked and the ventral shield is not well preserved.The head shield is 14mm in width22mm in length of preservation.In holotype the orbits and pineal body were not clear preserved,but the posterior part of the sensory canals can be watched clearly.The characters of ventral carapace of the head shield are preserved more clear in 5-27-13,5-27-6.So,the ventral rim and ventral plates can be reconstructed.Order and Family indent.Genus Cyclocephalaspis Wang & Guo 2011 Diagnosis:Median size agnathan fossils.Head shield plane,round in shape.Single carapace cover head shield and turn to ventral aspect forming wider ventral rim.No median dorsal opening.Rostrum margin process posterior slightly.Pineal body and orbits are smaller.Soc,ioc and ldc sensory canals in head shield distributed.Six paired of branchial fossae and external branchial openings in branchial region.Posterior median process is in posterior margin.Ornamentation composed of fine and small tuberculars.Type species Cyclocehpalaspis haoae Wang & Gou 2011 Holotype:a complete head shield,dorsal and ventral aspects,7-17-4 Other material:7-20-2,7-19-2-1,BCY-015-12-1,2,3,BCY-015-10-1.Locality and horizon:same to Bachuiaspis elegans Wang & Guo.Description:The holotype is a median size head shield of agnathan fossil.It is 37mm in width 34mm in length preserved.The posterior margin possessed a posterior process in the median part.The sensory canal system is more clear in holotype 7-17-4,especially the ltc and mtc sensory canals,and there are the characters and outline of Avp,Vp,VR preserved very well in 7-17-4 specimen.In the ventral aspect there are six paired of external branchial openings preserved in 7-17-4.The orbits,pineal body are not well preserved,orbits are small in BCY-015-12-1 specimen,The oral is very clear in BCY-015-10-1,and the branchial fossae in BCY-015-12-2 preserved.关键词
古脊椎动物/系统生物学/晚奥陶世/新疆巴楚地区Key words
paleo-vertebrates/systematic biology/Late Ordovician/Bachu area, Xinjiang引用本文复制引用
王士涛,郭宪璞..新疆巴楚地区中—晚奥陶世古脊椎动物系统生物学研究[J].地质论评,2017,63(6):1602-1612,11.基金项目
本文为国家自然科学基金资助项目(批准号:41372025)的成果.This work was financially supported by the National Natural Science Foundation of China (Grant nos.41372025). （批准号:41372025）
