An Early Ordovician (Floian) asterozoan (Echinodermata) of problematic class-level affinities

Author:

Blake Daniel B.ORCID,Gahn Forest J.,Guensburg Thomas E.ORCID

Abstract

AbstractFalloaster anquiroisitus new genus new species (Asterozoa, Echinodermata) is described from the Floian (Early Ordovician) Garden City Formation of Idaho. The new taxon is known from a single small specimen. Because of weathering, remaining disk elements are incomplete. Dorsal surfaces of the ambulacral ossicles of two arms are available, one well preserved, whereas those of a third arm expose the ambulacrals essentially as they would appear in ventral view. Ambulacral ossicles were all but entirely lost on the remaining two arms.Albeit asterozoan, F. anquiroisitus is not assignable at the class level. It is suggestive of the Asteroidea in presence of a domal disk, five abruptly tapering triangular, arched arms, and ambulacral ossicles vaulted to form a furrow. Ambulacral morphology, including the presence of very large podial pores, is unlike that of early asteroids. In addition, no adambulacral or other virgal-series derivatives are present; ambital framework ossicles are absent; a single series of enlarged, plate-like arm ossicles, one series on each side of the arm, come together at the arm midline; and the plate-like series were supported laterally by recurved ambulacral margins. Only remnants of the disk near the periphery survive, these of overall expression unlike any other echinoderm, including asterozoans. The mouth frame is unknown. Falloaster anquiroisitus is argued to represent an extinct lineage apart from the four recognized asterozoan classes, thereby joining a limited number of other problematic early Asterozoa.UUID: http://zoobank.org/a13a5417-44b6-4ac3-90cf-9dc8fb5902bd

Publisher

Cambridge University Press (CUP)

Subject

Paleontology

Reference25 articles.

1. Evolution Within a Bizarre Phylum: Homologies of the First Echinoderms

2. A new asteroid genus from the Carboniferous of Ireland and its phylogenetic position and paleoecology;Blake;Irish Journal of Earth Sciences,1995

3. A monograph of the British Palaeozoic Asterozoa

4. Thoral M. , 1935, Contribution à l’étude paléontologique de l'Ordovicien inférieur de la Montagne Noire et révision sommaire de la faune cambrienne de la Montagne Noire [Ph.D. thesis]: Paris, l'Université de Paris, 363 p.

5. Two Ordovician asterozoans (Echinodermata) of problematic affinities

Cited by 3 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3