...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta Palaeontologica Polonica >Soft anatomy of the early Cambrian arthropod Isoxys curvirostratus from the Chengjiang biota of South China with a discussion on the origination of great appendages
【24h】

Soft anatomy of the early Cambrian arthropod Isoxys curvirostratus from the Chengjiang biota of South China with a discussion on the origination of great appendages

机译：华南澄江生物区早期寒武纪节肢动物弯曲体的软解剖及其重要附属物的起源

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An updated reconstruction of the body plan, functional morphology and lifestyle of the arthropod Isoxys curvirostratus is proposed, based on new fossil specimens with preserved soft anatomy found in several localities of the Lower Cambrian Chengjiang Lagersttte. The animal was 24 cm long and mostly encased in a single carapace which is folded dorsally without an articulated hinge. The attachment of the body to the exoskeleton was probably cephalic and apparently lacked any well-developed adductor muscle system. Large stalked eyes with the eye sphere consisting of two layers (as corneal and rhabdomeric structures) protrude beyond the anterior margin of the carapace. This feature, together with a pair of frontal appendages with five podomeres that each bear a stout spiny outgrowth, suggests it was raptorial. The following 14 pairs of limbs are biramous and uniform in shape. The slim endopod is composed of more than 7 podomeres without terminal claw and the paddle shaped exopod is fringed with at least 17 imbricated gill lamellae along its posterior margin. The design of exopod in association with the inner vascular (respiratory) surface of the carapace indicates I. curvirostratus was an active swimmer. Morphological comparisons demonstrate that species of Isoxys were diverse in feeding habits and occupied a very broad morphospace, i.e., carapace bivalved or a single shield, the pre-oral limbs antenniform or modified into great appendages, the succeeding endopods slim or stout. This casts doubt on the current taxonomy that assigns all species to a single genus, and on any presumed lifestyle of Isoxys extrapolated to the generic level. Finally, since I. curvirostratus and I. acutangulus carry a pair of great appendages, Isoxys has recently been placed into the great appendage arthropods. Such placement might be inadequate because the homology of the great appendages can not be established.
机译：基于在下寒武纪澄江拉格斯特几个地方发现的具有保留的软解剖结构的新化石标本，提出了节肢动物Isoxys curvirostratus的身体计划，功能形态和生活方式的更新重建。该动物长24厘米，大部分被单个甲壳包裹，该甲壳在背侧折叠而没有铰接铰链。身体与外骨骼的附着可能是头侧的，并且显然缺乏任何发达的内收肌系统。大型球茎眼球突出于背甲的前缘，其眼球由两层组成（如角膜和横纹肌结构）。这个特征，加上一对额叶附肢，每个附肢有五个刺突，每个刺突都长出坚硬的刺状突起，表明它是猛禽。接下来的14对肢体双bi且形状均匀。纤细的内足由超过7个没有末端爪的足突组成，并且桨状外足在其后缘边缘饰有至少17个br状薄片边缘。外甲的设计与甲壳的内部血管（呼吸）表面有关，表明弯曲弧菌是活跃的游泳者。形态学比较表明，异氧基的种类具有不同的摄食习惯，并且占据了非常宽的形态空间，即甲壳双壳或单盾形，口前肢呈触角状或修饰成巨大的附属物，后继的内足细小或粗壮。这使人们对当前将所有物种归为一个属的分类法，以及推断到一般水平的任何假定的Isoxys生活方式产生怀疑。最后，由于弯曲弯曲杆菌和尖角弯曲杆菌带有一对大的附肢，最近将异氧基放入了巨大的附肢节肢动物中。这样的放置可能是不适当的，因为无法确定大附件的同源性。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号