Briggs Derek E G, Sutton Mark D, Siveter David J, Siveter Derek J
Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA.
Proc Biol Sci. 2004 Jan 22;271(1535):131-8. doi: 10.1098/rspb.2003.2593.
A new three-dimensionally preserved arthropod, Cinerocaris magnifica, from the Wenlock Series (Silurian) of Herefordshire, UK, is described and assigned to the Phyllocarida (Crustacea). The description and reconstruction are based on specimens that have been serially ground, reconstructed by computer and rendered in three dimensions as coloured virtual models. Cinerocaris magnifica displayed the tagmosis characteristic of phyllocarids, with eight thoracic and seven abdominal somites, terminating in a telson with furca. The remarkable preservation of the appendages makes this the earliest completely known malacostracan crustacean. Two pairs of antennae (the first with two flagella) were followed by a mandible and first maxilla, each with a slender palp-like ramus. The second maxilla consisted of a limb stem with endites and an endopod that tapered distally. There was no exopod. The thoracopods comprised a limb stem with six or seven endites, an arrangement previously known only in entomostracans, and an endopod with about five endites. Flap-like outer rami correspond to an exopod and epipods. The pleopods bore two long slender oar-blade-like rami. Cladistic analysis places C. magnifica as a plesion within the Echinocaridina. It provides critical evidence of the limb morphology of an early malacostracan, which will be important in understanding crustacean evolution.
一种新的三维保存的节肢动物，华丽煤溪虾（Cinerocaris magnifica），来自英国赫里福德郡的温洛克统（志留纪），被描述并归入叶虾亚纲（甲壳纲）。描述和重建基于经连续研磨的标本，通过计算机重建并渲染为彩色三维虚拟模型。华丽煤溪虾显示出叶虾类的体节特征，有八个胸节和七个腹节，末端是带有尾叉的尾节。附肢的显著保存使其成为已知最早的完全保存的软甲亚纲甲壳动物。两对触角（第一对有两条鞭毛）之后是一对大颚和第一小颚，每对都有一个细长的似触须状的分支。第二小颚由带有内叶的肢体主干和向远端逐渐变细的内肢组成。没有外肢。胸足包括一个带有六个或七个内叶的肢体主干，这种排列以前仅在鳃足亚纲中已知，以及一个带有大约五个内叶的内肢。瓣状的外分支对应于外肢和上肢。腹足有两条长而细长的桨状分支。分支系统发育分析将华丽煤溪虾置于海刺虾目内的一个近裔共性分类单元。它提供了早期软甲亚纲肢体形态的关键证据，这对于理解甲壳动物的进化将具有重要意义。
