Early Cambrian trilobite larvae and ontogeny of Ichangia ichangensis Chang, 1957 (Protolenidae) from Henan, China
Early Cambrian trilobite larvae and ontogeny of Ichangia ichangensis Chang, 1957 (Protolenidae) from Henan, China
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DOI：
10.1017/s0022336000027591
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发表时间：
1999-01-01
影响因子：
1.4
通讯作者：
Pratt, BR
中科院分区：
文献类型：
--
作者：
Zhang, XG;Pratt, BR
在河南淅川下寒武统水沟口组中发现了一个磷酸化龄期，属于原虫类Ichangia ichangensis Chang，1957，以及两个未定分类群。三种幼虫形态在一定程度上相似，具有相对简单的身体平面，并且Iichangensis的原甲与椭圆头体的Palaeolenus lantenoisi Mansuy的原甲表现出一般的相似性。然而，它们的早期个体发育过程表现出微妙而明显的差异。一组未分配的protaspides拥有一个矢状眉间沟和原缘刺与分支的极端。其他未指定的原蝎蛉有特别长的颊脊和原缘脊。这些幼虫的详细保存揭示了微妙的结构变化，有助于提供一个框架，以评估早寒武世三叶虫之间的关系。
The Lower Cambrian Shuigoukou Formation of Xichuan, Henan province, China, yielded phosphatized instars belonging to the protolenid Ichangia ichangensis Chang, 1957, and two undetermined taxa. With relatively simple body plans, the three larval forms resemble each other to some extent, and protaspides of I, ichangensis show general similarities to those of the ellipsocephalid Palaeolenus lantenoisi Mansuy. However, their early ontogenetic processes exhibit subtle yet distinct differences. One group of unassigned protaspides possesses a sagittal glabellar furrow and protomarginal spines with branching extremities. The other unassigned protaspides bear especially long genal and protomarginal spines. The detailed preservation of these larvae reveals delicate structural variations that help provide a framework for evaluating relationships among Early Cambrian trilobites.