• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Systematic Palaeontology >A SYSTEMATIC REVISION OF Thaleops (TRILOBITA: ILLAENIDAE) WITH NEW SPECIES FROM THE MIDDLE AND LATE ORDOVICIAN OF OKLAHOMA AND NEW YORK
【24h】

A SYSTEMATIC REVISION OF Thaleops (TRILOBITA: ILLAENIDAE) WITH NEW SPECIES FROM THE MIDDLE AND LATE ORDOVICIAN OF OKLAHOMA AND NEW YORK

机译：塔里奥普斯（TRILOBITA：ILLAENIDAE）的系统修订，带有来自俄克拉荷马州和纽约州中晚期奥陶纪的新物种

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

Illaenus Dalman, 1827 has long served as a wastebin for effaced trilobite species and the problem has been compounded in North America by the addition of Thaleops Conrad, 1843 and Nanillaenus Jaanusson, 1954. This study takes the first step toward defining the relationships of Laurentian taxa within this group using cladistic methods. Parillaenus Jaanusson, 1954 forms a monophyletic group based on pygidial morphology that is distinct from Illaenus. Our analysis indicates that Illaenus is paraphyletic and requires major revision. Thaleops is a large group of species whose monophyly is supported by an unambiguous apomorphy: the presence of long articulating facets on the pygidium that are oriented at a high angle to the anterior margin of the pygidium. All but one basal member of the clade possesses a second apomorphy, posteriorly positioned palpebral lobes. Nanillaenus is not monophyletic and is synonymised with Thaleops. Several Laurentian species originally identified as Illaenus are reassigned to Thaleops. Seventeen previously named species are revised and re-illustrated, four of which (I. arcturus Hall, 1847; I. clavifrons Billings, 1859; I. punctatus Raymond, 1905; I. americanus Billings, 1859) are restricted to the type material. In addition, four new species, T. anusacerbissima, T. jaanussoni, T. mobydicki and T. laurentiana, are described from the Middle and Upper Ordovician Bromide and Viola Springs formations of Oklahoma and the Trenton Group of New York.
机译：1827年的Illaenus Dalman长期以来一直是外来三叶虫物种的废物箱，在北美，1843年的Thaleops Conrad和1954年的Nanillaenus Jaanusson的加入使这一问题更加复杂。这项研究迈出了确定劳伦斯分类群关系的第一步在这个群体中，采用了进化论方法。 Parillaenus Jaanusson，1954年建立了一个基于形态的单系群，该群不同于Illaenus。我们的分析表明，Illaenus具有寄生性，需要进行重大修订。 Thaleops是一大类物种，它们的单性由明确的无性形态支持：在虫上存在长的关节小平面，这些小关节与虫的前缘成高角度。除一个基部外，所有基部均具有第二个畸形，位于后部的睑裂。 Nanillaenus不是单系的，而是Thaleops的代名词。最初被鉴定为Illaenus的几种Laurentian物种被重新分配给Thaleops。修改并重新图示了先前命名的17个物种，其中四个（I. arcturus Hall，1847年； I。clavifrons Billings，1859年； I。punctatus Raymond，1905年； I。americanus Billings，1859年）仅限于类型材料。此外，还从俄克拉荷马州的奥陶纪中上奥陶纪溴化物和维奥拉温泉形成以及纽约特伦顿集团描述了四个新物种，即T. anusacerbissima，T。jaanussoni，T。mobydicki和T. laurentiana。

著录项

相似文献

  • 外文文献
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