Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods

doi:10.1017/S0016756817000279

	Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods
	Han Zeng (曾晗); Fangchen Zhao (赵方臣); Zongjun Yin (殷宗军); Maoyan Zhu (朱茂炎)
	2017
发表期刊	Geological Magazine
ISSN	0016-7568
卷号	154 期号:6 页码:1306-1328
摘要	Appendage anatomy contributes crucial data for understanding the evolution and ecology of Euarthropoda. The Palaeozoic trilobites show a great diversity of exoskeletons in the fossil record. However, soft parts, especially appendages, have only been discovered from a few trilobite species. Here we report extraordinarily preserved appendages in the trilobite species Hongshiyanaspis yiliangensis Zhang & Lin in Zhang et al. 1980 (Redlichiida, Metadoxididae) from a single mudstone layer of the Xiazhuang fossil assemblage within the Hongjingshao Formation (Cambrian Series 2, Stage 3) near Kunming, Yunnan, SW China. The appendages exhibit the common architecture revealed by other trilobites and artiopods by consisting of a pair of uniramous antennae followed by a series of paired homonomous biramous limbs. The antennae in holaspid individuals comprise up to 27 spinous podomeres and their ontogeny occurs by lengthening of the podomeres. The post-antennal biramous limbs are similar to those in other polymerid trilobites and artiopods by having a single-segmented protopodite and an endopodite comprising seven segments, but possess a unique wide tripartite exopodite with long setae. Sophisticated appendage anatomy, including the body-limb junction, fine setae, putative muscle bundles and duct-type tissues, are also revealed. Appendages of trilobites, artiopods and other upper stem-group euarthropods are compared and summarized. The H. yiliangensis appendages highlight the high morphological disparity of exopodites and the conservativeness of endopodites in trilobites and artiopods. This morphological pattern, together with similar body patterning seen in crustaceans but not in chelicerates, supports the mandibulate affinities of trilobites and at least some artiopods.
关键词	arthropods trilobites appendages Mandibulata Cambrian soft-part preservation
DOI	10.1017/S0016756817000279
收录类别	SCI
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000413978800011
出版者	CAMBRIDGE UNIV PRESS
文献类型	期刊论文
条目标识符	http://ir.nigpas.ac.cn/handle/332004/14073
专题	中国科学院南京地质古生物研究所中国科学院南京地质古生物研究所其他
通讯作者	Fangchen Zhao (赵方臣)
推荐引用方式 GB/T 7714	Han Zeng ,Fangchen Zhao ,Zongjun Yin ,et al. Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods[J]. Geological Magazine,2017,154(6):1306-1328.
APA	Han Zeng ,Fangchen Zhao ,Zongjun Yin ,&Maoyan Zhu .(2017).Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods.Geological Magazine,154(6),1306-1328.
MLA	Han Zeng ,et al."Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods".Geological Magazine 154.6(2017):1306-1328.