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早寒武世腕足动物的形态解剖及其进化

发表时间:2008-01-15  浏览量:1515  下载量:608
全部作者: 张志飞,舒德干
作者单位: 西北大学地质学系
摘 要: 腕足动物是身裹双壳的海生无脊椎动物,与小壳化石最早一起出现在早寒武世. 在地质记录中它们通常仅有壳体保存,贝体内部组织很难保存为化石。因此我们对早期腕足的解剖结构只能从它们的现生类群进行推测,推测结果的可靠性也难以验证或证实。幸运的是我国澄江化石库腕足动物精细保存了腕足动物的软体组织,如肉茎、刚毛、外套管、纤毛环、消化道和界定清楚的内脏区,为了解早期腕足动物的起源和特征进化提高了重要的化石证据。研究表明寒武纪早期腕足动物已经具有了高度发育的复杂组织器官,其脉管系统发育、形态分异较大,纤毛环普遍为螺旋类型,肉茎可分为纤细锚定和粗壮固着两大类型,肉茎附着型是寒武纪腕足生活的最普遍生活方式。
关 键 词: 古生物学与地层学;早寒武世;澄江动物群;腕足动物;特征进化;生活方式
Title: A perspective of Character evolution of Early Cambrian brachiopods
Author: ZHANG Zhifei, SHU Degan
Organization: Department of Geology, Northwest University
Abstract: Brachiopods, a group of benthic suspension-feeding marine invertebrates, made their first appearance in the Lower Cambrian, together with widespread “Small Shelly Fossils”. They are, however, known largely based on the fossil records of shells. Consequently, our knowledge of Palaeozoic brachiopods anatomy relies heavily on analogies with their extant relatives, yet these analogies have been untested regarding stem-group clades. Fortunately, brachiopods from the celebrated Chengjiang fauna have exquisitely preserved soft-tissues, including pedicles, setae, mantle canals, lophophores, digestive tracts and well-defined visceral regions, which reveal the body plans and evolutionary acquisition of morphological novelties of the early stocks, and also provide a good opportunity for testing the analogies with the stem goups from the extant reprsentatives. These fossils have corroborated the view that brachiopods developed complex organization of tissues, and achieved considerable evolutionary success already by the onset of Cambrian explosion. Studies of Chengjiang brachiopods suggest that an early spirolophe was the most common configuration of lophophores at least from the bigining of the Cambrian, and that attachment by a pedicle to the substrate was probably the most commn relationship of Cambrian brachiopods with the substrate where they inhabited.
Key words: Early Cambrian; Chengjiang fauna; brachiopods; character evolution; lifestyle
发表期数: 2008年5月第1期
引用格式: 张志飞,舒德干. 早寒武世腕足动物的形态解剖及其进化[J]. 中国科技论文在线精品论文,2008,1(1):25-41.
 
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