Appendages of early Cambrian Eoredlichia (Trilobita) from the Chengjiang biota, Yunnan, China
Appendages of early Cambrian Eoredlichia (Trilobita) from the Chengjiang biota, Yunnan, China
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中国云南澄江生物群早期寒武世 Eoredlichia (Trilobita) 的附属物
DOI：
10.1017/s1755691009008093
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发表时间：
2008-01-01
影响因子：
1.2
通讯作者：
Yuan, Zibo
中科院分区：
文献类型：
--
作者：
Hou, Xianguang;Clarkson, Euan N. K.;Yuan, Zibo
云南早寒武世成江生物群中发现了多刺棘叶三叶虫Eoredlichia intermedia的关节外骨骼，其中一些附属物保存异常完好。中等大小的holaspis的一对无名触角都由46-50个短节（节）组成，每个短节的内缘附近都有一个细刺。触角后面有21对著名的肢：3对在头节下面，1对在15节胸椎下面，可能还有3对在小臀肌下面。内足由宽广的基底和七个足部组成，其中足部分为三个末端棘。外足部呈叶片状，根据一种解释，背侧与内足部的基部铰接；另一种说法是，内足部和外足部都是从基部分离出来的，后者是独立的，不构成内足部的一部分。外足有突出的前缘，沿后缘约有四十根长丝，沿圆形远叶有短刚毛。复叶三叶虫的基本附属物特征，以及肠道，与其他已知的寒武纪多聚三叶虫相似，这些三叶虫属于更遥远的分支。
ABSTRACT The early Cambrian Chengjiang biota in Yunnan, southern China has yielded many articulated exoskeletons of the spiny redlichiid trilobite Eoredlichia intermedia, of which some have their appendages exceptionally well preserved. Both of the paired uniramous antennae of a medium-sized holaspis consist of 46–50 short segments (articles), each of which bears a fine spine near its inner edge. Behind the antennae there are twenty-one pairs of biramous limbs: three pairs are situated underneath the cephalon, one pair underneath each of the fifteen thoracic segments, and probably three pairs underneath the small pygidium. The endopod consists of a broad basis and seven podomeres, of which the last is divided into three terminal spines. The exopod is blade-like, and according to one interpretation, is dorsally hinged to the basis of the endopod; an alternative suggestion being that both the endopod and exopod are split from the basis, the latter being independent and not forming part of the endopod. The exopod has a prominent anterior rim, and possesses about forty long filaments along the posterior margin, and short setae along the rounded distal lobe. The basic appendage features of the redlichiid trilobites, and likewise the gut, are comparable to those of other known Cambrian polymerid trilobites that belong to more distantly related clades.