CHANCELLORIID SCLERITES FROM THE LOWER CAMBRIAN (MEISHUCUNIAN) OF EASTERN YUNNAN, CHINA, AND THE EARLY HISTORY OF THE GROUP
CHANCELLORIID SCLERITES FROM THE LOWER CAMBRIAN (MEISHUCUNIAN) OF EASTERN YUNNAN, CHINA, AND THE EARLY HISTORY OF THE GROUP
复制标题
中国云南东部下寒武统（梅树村阶）的Chancelloriid骨片及其早期历史
DOI：
10.1111/pala.12090
复制
发表时间：
2014-07-01
期刊：
影响因子：
2.6
通讯作者：
Porter, Susannah M.
中科院分区：
文献类型：
--
作者：
Moore, John L.;Li, Guoxiang;Porter, Susannah M.
钱梭状体是一群神秘的无根动物，上面覆盖着像玫瑰花一样的硬骨，外表像桶形仙人掌。它们只在寒武纪岩石中被发现。在小型壳类动物中，囊状体的分离巩膜广泛存在，但由于个体动物内部和个体动物之间的差异，它们已被证明难以分类学处理。本文报道了中国云南东部梅树村（下寒武统前三叶虫）的大样本球状硬石，包括来自朱家青组海段（会泽县海段朱家青段）和石烟头组（永山县小滩段）的材料。来自大海成员的材料似乎来自一个单一的物种，不规则的Chancelloriella。对不同样品形态型共现的统计分析表明，石盐头组样品中存在多个种，我们暂时将其归为四个种，即Allonnia erromenosa、Allonnia tetrathallis、Archiasterella charma sp. 11和Archiasterella cf. pentactina。因此，我们建议仔细研究大量分离的球胞体巩膜，可以识别不同的物种，为它们在进化或地层学研究中的应用提供可能性。特别是在华南地区，不规则长尾藻（Chancelloriella irregularis）似乎是Paragloborilus subglobosus - Purella squamulosa组合带和Watsonella crosbyi组合带的岩石特征，而Archiasterella和Allonnia则首先出现在上覆的Sinosachites flabelliformis - tanannuolina zhangwentangi组合带。因此，C. irregularis是最古老的具有充分特征的chancelloriids之一，相对于较年轻的形式，其硬膜的不规则性和较差的组织支持了一种假设，即chancelloriid硬膜是由原始分离元素融合而产生的复合结构，可能与halkieriids和其他腔骨硬膜生物的硬膜同源。射线在球状刚石中的排列与气泡在小气泡团中的排列之间的相似性表明，在许多情况下，球状刚石形式的各个方面是简单物理过程的结果。
Chancelloriids are a group of enigmatic sessile animals that are covered with sclerites shaped as rosettes of spines, producing an appearance like that of a barrel cactus. They are known only from Cambrian rocks. Isolated sclerites of chancelloriids are widespread in small shelly faunas, but they have proven difficult to treat taxonomically due to the variation within and between individual animals. We report on large samples of chancelloriid sclerites from the Meishucunian (pre‐trilobitic Lower Cambrian) of eastern Yunnan Province, China, including material from the Dahai Member of the Zhujiaqing Formation (the Zhujiaqing section, Dahai, Huize County) and the Shiyantou Formation (the Xiaotan section, Yongshan County). The material from the Dahai Member appears to come from a single species, Chancelloriella irregularis. Statistical analysis of morphotype co‐occurrences in different samples suggests that several species are represented in the material from the Shiyantou Formation, which we herein tentatively place in four species, Allonnia erromenosa, Allonnia tetrathallis, Archiasterella charma sp. nov. and Archiasterella cf. pentactina. We suggest therefore that careful study of large collections of isolated chancelloriid sclerites permits the identification of different species, opening the possibility of their use in evolutionary or stratigraphical studies. In particular, in South China, it seems that Chancelloriella irregularis is characteristic of rocks of the Paragloborilus subglobosus – Purella squamulosa Assemblage Zone and the Watsonella crosbyi Assemblage Zone, whilst Archiasterella and Allonnia first appear in the overlying Sinosachites flabelliformis – Tannuolina zhangwentangi Assemblage Zone. C. irregularis is thus amongst the oldest well‐characterized chancelloriids, and the irregularity and poor organization of its sclerites relative to those of younger forms support the hypothesis that chancelloriid sclerites are compound structures arising from the fusion of originally separate elements, perhaps homologous with sclerites of halkieriids and other coeloscleritophorans. The similarity between the arrangement of rays in a chancelloriid sclerite and the arrangement of bubbles in small bubble clusters suggests that in many cases, aspects of the form of chancelloriid sclerites are the result of simple physical processes.