新疆晚奥陶世鱼形动物  

The Late Ordovician fish-like animal from Xinjiang

作　　者：郭宪璞[1] 王士涛[1] 盖志琨[2] 赵子然[1] 丁孝忠[1] 李天福[1] GUO Xianpu;WANG Shitao;GAI Zhikun;ZHAO Ziran;DING Xiaozhong;LI Tianfu(Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,China)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国科学院古脊椎动物与古人类研究所,北京100044

出　　处：《地学前缘》2020年第6期341-346,共6页Earth Science Frontiers

基　　金：国家自然科学基金项目(41372025);中国地质调查局项目“全国陆域及海区地质图件更新与共享”(DD20290370)。

摘　　要：本文记述了新近发现的保存较好、具甲胄确切证据的奥陶纪鱼形动物化石。该化石采自新疆塔里木盆地巴楚县一间房地区依朗里克塔格山上奥陶统恰尔巴克组滨浅海紫红色砂屑灰岩中。对所发现的鱼形动物新属新种——优雅郝氏鱼(Haoina elegantia gen.et sp.nov.)进行了生物学系统描述。郝氏鱼是我国奥陶纪已知保存较完整的古脊椎动物化石,是新科——郝氏鱼科(Haoinaspididae fam.nov.)的科型属。并依据其独特的生物学特征建立新目——郝氏鱼目(Haoinaspidiformes ord.nov.),置于无颌超纲甲胄鱼纲之下。依据牙形石化石带的时代分布,恰尔巴克组属于晚奥陶世早期,即桑比期。新发现的鱼形动物化石包括一个较完整的背侧甲片,化石表面覆盖具有特征纹饰的外骨骼甲胄,大致可分为四种不同的类型;松果区位于头甲中前部;有宽大而深陷的背侧位眶凹,位于松果体稍前的两侧,瘤突组成的嵴在凹壁呈同心圆排列,眶凹呈喇叭状开口。感觉沟系统发育,具眶上感觉沟、主侧线感觉沟和嵴间感觉沟,显示出真皮及皮下组织的管孔系统结构。根据与其他地区鱼形动物的对比和生物特征,建立了具有古特提斯特色的新的鱼形动物古地理分区——奥陶纪郝氏鱼类巴楚鱼类古脊椎动物生物地理区系。这一化石是我国乃至亚洲目前已知发现最早具外骨骼确凿证据的鱼形动物。This paper is the first to report the discovery of a well-preserved Ordovician fish-like animal fossil with a reliable shield armor structure.The vertebrate fossil was collected from purplish-red sandy-limestone outcrops of coast-shallow marine facies that are part of the Upper Ordovician Qarbake Formation in the Yijianfang section,Bachu county,Xinjiang.The new genus and species has been denoted Haoina elegantia Guo&Wang as per the system of binomial nomenclature,and a new family(Haoinaspididae)and order(Haoinaspidiformes)have also been described based on the unique biological features of this species.The new genus describes an ostraeoderm,while the Qarbake Formation can be constrained to the Sandbian stage based on the conodont fossil zone.The fossil of the new fish-like animal preserves its dorsal shield armor and shows that the dorsal shield on its head is covered with ridges composed of complex tumors on the derma.The ridges can be subdivided into four types:The orbit openings are situated at the dorsal-front edge of the head shield with wide and deep orbit hollows.The pineal area is located at either side of the orbits.And the well-developed sensory canal system in the armor of the head shield shows the tube system texture of corium and subcutaneous tissues.Based on comparisons with the vertebrate biogeographic regions of other fossils,we suggest the establishment of a new fish-like animal typified in a proto-Tethys Ordovician Haoniaspid-Bachuiaspid vertebrate biogeographic province.This fossil is the oldest fish-like animal with a reliable exoskeleton found in China or even in Asia.

关 键 词：奥陶纪 鱼形动物 无颌类 郝氏鱼 新疆 

分 类 号：P52[天文地球—古生物学与地层学] P534.4[天文地球—地质学]