贵州剑河寒武系凯里组褶颊虫类三叶虫Xingrenaspis xingrenensis的蜕壳行为  

Moulting behaviour of the Ptychopariid trilobite Xingrenaspis xingrenensis from the Cambrian Kaili Formation in Jianhe,Guizhou

作　　者：陈圣光 赵元龙[1] 杨兴莲[1] 陈争鹏 赵小云 CHEN Sheng-guang;ZHAO Yuan-long;YANG Xing-lian;CHEN Zheng-peng;ZHAO Xiao-yun(College of Resource and Environmental Engineering,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学资源与环境工程学院,贵阳550025

出　　处：《古生物学报》2021年第1期176-186,共11页Acta Palaeontologica Sinica

基　　金：国家重点基础项目基金(2015FY310100-5);国家自然科学基金重大项目(41330101);国家自然科学基金(41772021,41962002,41662001,41702022)联合资助;中国地质调查局调查项目(DD20160120-04);贵州省科技基金(20204Y241)。

摘　　要：贵州东部寒武系苗岭统乌溜阶凯里组中上部保存了大量褶颊虫类三叶虫Xingrenaspis xingrenensis蜕壳标本,为揭示这类三叶虫的蜕壳行为提供了良好的材料。对比分析X.xingrenensis 106块蜕壳标本后分为如下3种保存类型:类型Ⅰ(63块),轴背构造(头盖、胸甲及尾板连接保存),未见活动颊及头甲的腹部结构;类型Ⅱ(2块),胸尾保持连接状态,头甲自头胸结合处断开后向后翻转180°,活动颊及头部腹面结构缺失或压于胸甲之下;类型Ⅲ(41块),头盖及胸尾连接保存,活动颊脱开在虫体周围或压于胸甲之下。从这3种保存类型中发现X.xingrenensis蜕壳方式不仅有通过头部缝合线打开产生的前蜕壳口来进行,也存在由头胸结合处的断口来完成蜕壳行为。从埋藏学方面来看,因蜕壳而形成的独特外壳组合的保存必须在静水沉积环境中,大量X.xingrenensis蜕壳标本的发现为凯里生物群为原地(近原地)埋藏提供了关键的证据。Abundant,well-preserved moulted ones(ecdyses)of ptychopariid trilobite Xingrenaspis xingrenensis found from the Cambrian Miaolingian Series,Wuliuan Stage Kaili Formation(middle and upper part)in eastern Guizhou,provide substantial material for revealing the moulting behavior of this trilobite lineage.Comparative analysis on 106 disarticulated exoskeletons of X.xingrenensis reveals that the preservation types can be divided into the following 3 styles:Style I(63 pieces):axial shield,the librigenal and ventral structure of the cephalon are displaced,while the cranidium,thorax and pygidium are mostly connected;StyleⅡ(2 pieces):The thorax and pygidium connected,the cephalon is disconnected from the cephalothoracic joint and turned back 180°,the librigenal and the ventral structure of the cephalon are missing or pressed under the thorax;StyleⅢ(41 pieces):The cranidium and thoracopygon are connected,and the librigenal area detached around the trilobite or pressed under the thorax.Based on these 3 preservation types,it was found that the moulting method of X.xingrenensis is not only carried out through the anterior exuvial gape created by the operation of the cephalic sutures,but also had the fracture at the joint of the cephalothoracic to complete the moulting behavior.Taphonomically,the preservation of distinguishing skeletal assemblage presumed to be resulted from moulting must be buried in a hydrostatic depositional environment,and the discovery of a large number of shedded exoskeletons of X.xingrenensis provides critical evidence for the in-situ(near-in-situ)burial of the Kaili Biota.

关 键 词：Xingrenaspis xingrenensis 保存类型 蜕壳方式 苗岭统乌溜阶 寒武系 

分 类 号：Q915[天文地球—古生物学与地层学]