An edrioasteroid from the Silurian Herefordshire Lagerstätte of England reveals the nature of the water vascular system in an extinct echinoderm.
An edrioasteroid from the Silurian Herefordshire Lagerstätte of England reveals the nature of the water vascular system in an extinct echinoderm.
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来自英国志留纪赫里福德郡 Lagerstätte 的一颗小行星揭示了已灭绝的棘皮动物的水血管系统的性质。
DOI：
10.1098/rspb.2017.1189
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Briggs DEG
中科院分区：
文献类型：
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作者：
Briggs DEG
棘皮动物的独特之处在于具有带管足的水脉管系统，其在生活形式中执行各种功能。在这里，我们报告的第一个例子保存管脚在一个灭绝的棘皮动物。该材料来自英国赫里福德郡的志留纪Lagerstätte，被分配给一个新的属和种，Heropyrgus disterminus。管足附着在复合辐间板的内表面，形成两组，一组在上，一组在下，这种排列在现存或灭绝的棘皮动物中从未报道过。盖板不存在，底板分离，从而形成通向口腔区域内部的大的永久入口。管脚可能捕获了进入口腔区域的食物颗粒和/或增强了呼吸。口腔表面的五角对称过渡到八列，其中板垂直偏移，导致螺旋外观。这种对称性的变化可能反映了早期棘皮动物轴向和轴外区进化发展的灵活性。
Echinoderms are unique in having a water vascular system with tube feet, which perform a variety of functions in living forms. Here, we report the first example of preserved tube feet in an extinct group of echinoderms. The material, from the Silurian Herefordshire Lagerstätte, UK, is assigned to a new genus and species of rhenopyrgid edrioasteroid,Heropyrgus disterminus. The tube feet attach to the inner surface of compound interradial plates and form two sets, an upper and a lower, an arrangement never reported previously in an extant or extinct echinoderm. Cover plates are absent and floor plates are separated creating a large permanent entrance to the interior of the oral area. The tube feet may have captured food particles that entered the oral area and/or enhanced respiration. The pentameral symmetry of the oral surface transitions to eight columns in which the plates are vertically offset resulting in a spiral appearance. This change in symmetry may reflect flexibility in the evolutionary development of the axial and extraxial zones in early echinoderm evolution.