{"title":"星形动物亚门的起源和一颗摩洛哥奥陶系小行星的重新描述","authors":"Daniel B. Blake , Frederick H.C. Hotchkiss","doi":"10.1016/j.geobios.2022.07.002","DOIUrl":null,"url":null,"abstract":"<div><p>A proposed new Ordovician asterozoan genus and species, <em>Cantabrigiaster fezouataensis</em>, has been recently described and assigned to the class Somasteroidea. An accompanying phylogenetic analysis treated twenty-two asterozoans and sixteen early non-asterozoans, one of the latter providing the outgroup. The phylogenetic hypothesis focused on derivation of the subphylum Asterozoa and emphasized the Crinoidea; <em>Cantabrigiaster fezouataensis</em> was interpreted as documenting a critical transition stage in the origin of the Asterozoa. The diagnosis for the proposed new generic name posits absence of ambital framework ossicles as the single character expression that distinguishes <em>Cantabrigiaster</em> among somasteroid genera. Ambital framework ossicular presence is documented here in the holotype and other members of type suite; <em>Cantabrigiaster</em> is synonymized with <em>Villebrunaster</em> Spencer and <em>V. fezouataensis</em> nov. comb. is redescribed. The data matrix for the former <em>Cantabrigiaster</em> phylogenetic analysis relies on an earlier study treating overall echinoderm construction. Expressions outlined in the earlier study are not amenable to transfer to a data matrix without evaluation of level of universality of each cited expression; such evaluations were not provided thereby leading to flawed phylogenetic conclusions that are rejected. An alternative hypothesis for the early history of the Asterozoa supported by aspects of the fossil record, that subphylum diversification preceded the origin of readily preserved skeletons, and therefore potentially no tenable pre-asterozoan outgroup candidate survives in the fossil record, has not been falsified.</p></div>","PeriodicalId":55116,"journal":{"name":"Geobios","volume":"72 ","pages":"Pages 22-36"},"PeriodicalIF":1.6000,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0016699522000389/pdfft?md5=0d8ea07ca762484a71d635d4f34191d1&pid=1-s2.0-S0016699522000389-main.pdf","citationCount":"1","resultStr":"{\"title\":\"Origin of the subphylum Asterozoa and redescription of a Moroccan Ordovician somasteroid\",\"authors\":\"Daniel B. Blake , Frederick H.C. 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引用次数: 1
摘要
新发现的奥陶系星虫属(Cantabrigiaster fezouataensis)被归属于星虫总纲。伴随的系统发育分析处理了22个星形动物和16个早期非星形动物,后者中的一个提供了外群。系统发育假说侧重于星形动物亚门的起源,并强调海百合总科;Cantabrigiaster fezouataensis被解释为记录了星形动物起源的一个关键过渡阶段。对提出的新属名的诊断假定缺乏雄心框架小骨作为区分Cantabrigiaster在一些小行星属中的单一字符表达。在全型和类型组的其他成员中记录了侧位框架听骨的存在;Cantabrigiaster与vilbrunaster Spencer和V. fezouataensis nov comb同义。重新描述。前Cantabrigiaster系统发育分析的数据矩阵依赖于早期对整个棘皮动物结构的研究。在先前的研究中概述的表达式不能在没有评估每个引用表达式的普遍性水平的情况下转移到数据矩阵中;没有提供这样的评价,从而导致有缺陷的系统发育结论被拒绝。另一个由化石记录支持的关于星形动物早期历史的假设是,亚门的多样化先于易于保存的骨骼的起源,因此化石记录中可能没有站得住脚的前星形动物外群候选人。这个假设尚未被证伪。
Origin of the subphylum Asterozoa and redescription of a Moroccan Ordovician somasteroid
A proposed new Ordovician asterozoan genus and species, Cantabrigiaster fezouataensis, has been recently described and assigned to the class Somasteroidea. An accompanying phylogenetic analysis treated twenty-two asterozoans and sixteen early non-asterozoans, one of the latter providing the outgroup. The phylogenetic hypothesis focused on derivation of the subphylum Asterozoa and emphasized the Crinoidea; Cantabrigiaster fezouataensis was interpreted as documenting a critical transition stage in the origin of the Asterozoa. The diagnosis for the proposed new generic name posits absence of ambital framework ossicles as the single character expression that distinguishes Cantabrigiaster among somasteroid genera. Ambital framework ossicular presence is documented here in the holotype and other members of type suite; Cantabrigiaster is synonymized with Villebrunaster Spencer and V. fezouataensis nov. comb. is redescribed. The data matrix for the former Cantabrigiaster phylogenetic analysis relies on an earlier study treating overall echinoderm construction. Expressions outlined in the earlier study are not amenable to transfer to a data matrix without evaluation of level of universality of each cited expression; such evaluations were not provided thereby leading to flawed phylogenetic conclusions that are rejected. An alternative hypothesis for the early history of the Asterozoa supported by aspects of the fossil record, that subphylum diversification preceded the origin of readily preserved skeletons, and therefore potentially no tenable pre-asterozoan outgroup candidate survives in the fossil record, has not been falsified.
期刊介绍:
Geobios publishes bimonthly in English original peer-reviewed articles of international interest in any area of paleontology, paleobiology, paleoecology, paleobiogeography, (bio)stratigraphy and biogeochemistry. All taxonomic groups are treated, including microfossils, invertebrates, plants, vertebrates and ichnofossils.
Geobios welcomes descriptive papers based on original material (e.g. large Systematic Paleontology works), as well as more analytically and/or methodologically oriented papers, provided they offer strong and significant biochronological/biostratigraphical, paleobiogeographical, paleobiological and/or phylogenetic new insights and perspectices. A high priority level is given to synchronic and/or diachronic studies based on multi- or inter-disciplinary approaches mixing various fields of Earth and Life Sciences. Works based on extant data are also considered, provided they offer significant insights into geological-time studies.