Oldest shrimp and associated phyllocarid from the Lower Devonian of northern Russia
Oldest shrimp and associated phyllocarid from the Lower Devonian of northern Russia
复制标题
俄罗斯北部下泥盆统最古老的虾和相关叶虾
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
Yuriy V. Deulin
中科院分区：
文献类型：
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作者：
J. Dzik;A. Ivantsov;Yuriy V. Deulin
在俄罗斯北部早泥盆世远洋环境中，大量出现成群的、弱硬化的真虾，这表明Eumalaco straca的体型起源于对在公海游泳的适应。由于晚奥陶世全球海洋环境的重建，它们很可能取代了它们的生态类似物--始祖类叶蝉类Carycaris。这可能解释了泥盆纪古陆虫的稀有性，以及记录它们与古陆虫的联系的困难。新的Eocarido与石炭纪的炭疽在外观和甲壳及附属物的弱硬化方面有相似之处，但缺乏其衍生特征。胸膜小叶的形态具有微小的刺，是所提出的新属和新种Archangeliphausia spinosa gen的唯一特征。ET sp.11月它的甲壳可能牢牢地与胸段背侧相连。该组合中唯一相关的化石代表了一种奇怪的始祖化石Pechoracaris aculicauda gen。ET sp.硬化性较弱的甲壳，没有任何铰链或吻板，但具有减少的鞭毛，极长的尾部刺和节肢动物转化为脊椎。
A mass occurrence of schooling, weakly sclerotized eocaridid shrimps in the Early Devonian pelagic environment of northern Russia suggests that the body-plan of the Eumalacostraca originated as an adaptation to swimming in the open sea. They probably replaced their ecological analogues, the archaeostracan phyllocarids Caryocaris, as a consequence of the rebuilding of the global marine environment during the later Ordovician. This may explain the rarity of the eumalacostracans in the Devonian and the difficulty with documenting their links with the archaeostracans. The new eocaridid shows similarities to the Carboniferous Anthracophausia in the general appearance and weak sclerotization of the carapace and appendages, but lacks its derived characters. The morphology of the pleural lobes, which have minute spines, is the only identified distinguishing character of the proposed new genus and species Archangeliphausia spinosa gen. et sp. nov. Its carapace was probably firmly connected dorsally with the thoracic segments. The only associated fossils of the assemblage represent a bizarre archaeostracan Pechoracaris aculicauda gen. et sp. nov., with a weakly sclerotized carapace lacking any hinge or rostral plates but with reduced furca, an extremely long caudal spine and pleopods transformed into spines. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142, 83–90.