寒武纪软舌螺壳体形态解剖研究与冠轮动物演化  

Advances in the soft anatomy and skeletal microstructures of Cambrian hyoliths in China and their implications for lophotrochozoan evolution

作　　者：刘璠 张志飞[1] Christian B.Skovsted Fan Liu;Zhifei Zhang;Christian B.Skovsted(Shaanxi Key Laboratory of Early Life and Environments and Department of Geology,State Key Laboratory of Continental Dynamics,Northwest University,Xi’an 710069,China;Department of Palaeobiology,Swedish Museum of Natural History,Stockholm SE-10405,Sweden)

机构地区：[1]西北大学地质学系,大陆动力学国家重点实验室,陕西省早期生命与环境重点实验室,西安710069 [2]Department of Palaeobiology,Swedish Museum of Natural History,Stockholm SE-10405,Sweden

出　　处：《科学通报》2021年第27期3631-3644,共14页Chinese Science Bulletin

基　　金：国家自然科学基金(41890844,41720104002,41425008,41621003,41772002,41621003);高等学校学科创新引智计划(D17013);国家留学基金公派研究生项目(CSC 201906970019)资助。

摘　　要：软舌螺是一类寒武纪出现并于二叠纪末灭绝的古生代海生无脊椎动物,具有重要的地层划分与对比意义.但是对于该动物本身生物属性等问题一直莫衷一是,近年中国寒武纪早期的特异型埋藏化石库中发现了大量保存软躯体的珍稀软舌螺动物化石.结合华南、华北同期碳酸盐岩沉积地层中的壳体化石,系列报道将软舌螺的化石生物学、壳体矿化和分类系统学研究推到新的高度,为探讨寒武纪大爆发壳体动物的演化,尤其是冠轮动物的系统学提供新的化石证据.澄江动物群的直管螺目三槽螺属化石发现保存有粗大的扇状触手器官,其基部可以在壳体内自由伸缩,与触手基部固定的触手冠动物明显不同,表明软舌螺与触手冠动物具有不同的生理结构和取食机制.综合最新微细结构的发现,支持软舌螺是一类与软体动物关系紧密的冠轮动物.软舌螺新材料的研究对寒武纪大爆发后生动物的演化提出了新的科学问题:后生动物在矿化体制发生演化中到底是整个壳体出现早,还是多骨片的骨骼系出现早——即形态上完整的生物壳体是由多个骨片愈合而成,还是反之.如何将矿化的整壳和骨片系与壳体内部组织器官和显微结构进行有效的极向系统分析,是未来冠轮动物进化生物学和古生物系统学研究的共同挑战.Hyolitha is an extinct enigmatic marine invertebrate group that ranges throughout the Palaeozoic,from the early Cambrian to the endPermian mass extinction.As one of the most dominant benthic animals in Cambrian and Ordovician strata,hyoliths are common components of both small shelly fossil assemblages from carbonates and Konservat Lagerst?tten where their soft tissues are preserved in exquisite detail.Despite this wealth of specimens,the biological affinity and life mode of hyoliths are still unclear and have long been controversial.However,based on the abundant and diverse record of Cambrian fossil hyoliths found in North America,Greenland,Australia and China,considerable advances have recently been made.Discoveries from the Cambrian of China reported herein play a significant role in revealing the morphology of hyoliths,in particular,from the famous exceptionally preserved Chengjiang and Guanshan biotas where delicate anatomical details are fossilized,and the well-known Small Shelly Fossil assemblages of the Shuijingtuo and Xinji Formations,which preserve shell microstructures.These new fossil discoveries have significant implications for interpreting the shell morphology,ultrastructure,soft part anatomy,life mode,and as discussed here,the biological affinity of hyoliths.The new data and interpretations provide novel ideas on the origin and early evolution of these shell-bearing animals during the Cambrian explosion,with particular implications on the evolutionary history of lophotrochozoans.With a brief review and history of the group,the present paper summarizes the significant progress made regarding our knowledge of Cambrian hyoliths from China during the past decade,outlining new fossil evidence obtained from both the soft anatomy and shell microstructure.Through a series of techniques,such as scanning electron microscope(SEM),microtomography(micro-CT)and nondestructive Micro X-ray Fluorescence(μ-XRF),in addition to the more traditional observation under light microscopy,new internal anatomical structure

关 键 词：软舌螺 寒武纪 壳体结构 解剖学 摄食器官 消化道 

分 类 号：Q915[天文地球—古生物学与地层学]