打开APP

Lethaia:奥陶纪末大灭绝后复苏—辐射期全球腕足动物

  1. 复苏
  2. 大灭绝
  3. 奥陶纪末
  4. 腕足动物
  5. 辐射期

来源:南京地质古生物研究所 2014-03-15 15:05

生物大灭绝后新的演化阶段是动物群再次建群(repopulation)的关键基础所在。

生物大灭绝后新的演化阶段是动物群再次建群(repopulation)的关键基础所在。研究大灭绝后生物的复苏与辐射对揭示生物宏演化过程、规律和型式是一个不可缺少的环节。志留纪兰多维列世埃隆期(Aeronian)是奥陶纪末大灭绝后腕足动物的首次复苏-辐射期。最近,中国科学院南京地质古生物研究所戎嘉余院士与英国自然历史博物馆Robin Cocks博士在国际地层古生物学刊物LETHAIA上合作发表了该时期全球海底占优势的腕足动物的综合研究,为该事件后的复苏-辐射早期研究提供了新的证据。

在对华南(SC)、阿瓦隆尼亚(A)、波罗迪卡(B)、劳伦(L)、西伯利亚(SB)、冈瓦纳及其他周缘许多小块体的埃隆期200余个腕足动物属进行系统分类、古生态和古地理分布分析的基础上,在相对可靠的地层对比的框架下,从全球视野观察,就不同阶元的多样性、分类组成、群落生态和古生物地理等四方面论述了奥陶纪末大灭绝后腕足动物的复苏-辐射早期的特征,得出了如下结论:1)与鲁丹期(大灭绝后残存期)“幸存分类单元”占优势不同,埃隆期腕足类多样性剧增,数量最多的4大类群(正形贝目、扭月贝目、无洞贝目和五房贝目)在组分变化上差异明显,后两目的属数分别递增为残存期的近2倍与4倍,而残存期占优势的前两者却递增有限,揭示了这次灭绝导致大类群发生“优势替代”的过程,而这一过程对古生代随后腕足动物的宏演化有着不同寻常的意义;2)埃隆期腕足动物产生了一大批新的类群(主要是超科级,如小嘴贝目、无窗贝目和石燕贝目等),这些类群后来在志留纪晚期和泥盆纪海域占据优势且广泛分布,成为古生代腕足动物演化的重要成员,是本期腕足动物辐射的重要标志;3)与残存期腕足动物生存范围较窄(多数为较浅水生境)不同,复苏-辐射早期全球腕足动物占据了更为广阔的生态位,如平底、礁相海域,并开始占领新的深水底域环境;4)采用数理统计方法,揭示了SC埃隆期腕足动物群所具备的强烈地方特色(如拥有大批土著属、无洞贝目在先、五房贝目跟进开始辐射、正形贝目等明显稀缺)、在古地理上相对隔离及与其他各区最疏远的亲缘关系,后者也可能与缺少深水动物群有关;5)亲缘关系指数显示,埃隆本文研究区域可分成两大组合,即SC和ABL;而SB的古生物地理数据与它们相似性较小,推测与古地理位置远近有关;SC与ABL在古地理位置上相距较远,腕足动物群相似性表明,西向的南北赤道环流是导致SC与ABL在腕足动物交流的主要通道。(生物谷Bioon.com)

生物谷推荐的英文摘要

Lethaia            DOI: 10.1111/let.12042

Global diversity and endemism in Early Silurian (Aeronian) brachiopods

Jiayu Rong1, L. Robin M. Cocks2

Silurian brachiopods of Middle Llandovery (Aeronian) ages are reviewed, and 215 genera are identified here, compared with 109 in the preceding Early Llandovery (Rhuddanian), indicating a recovery-radiation interval after the end-Ordovician mass extinction. The chief regions in which they are found are the continents of South China, Avalonia-Baltica, Laurentia and Siberia, which were all at tropical latitudes with the exception of Avalonia. In addition, the very large superterrane of Gondwana, although with patchy brachiopod distribution, included temperate faunas, as well as subtropical faunas (in Iran and Afghanistan). Aeronian brachiopods greatly increased in diversity, with dominance of four major groups: orthides and strophomenides (which had flourished previously in the Rhuddanian), pentamerides and atrypides (which became dominant in the Aeronian), and many newly evolved taxa, and occupied deeper water and wider ecological niches (level bottom and reef) than those in the Rhuddanian. Each of the continents has some endemic genera, but there is a greater proportion of them in South China, where some groups (such as the pentamerides and atrypides) are more diverse and others, such as the orthides, are much less common than elsewhere. Affinity indices (AI) show that two megaunits can be recognized: South China and Avalonia-Baltica-Laurentia (ABL); Siberia seems to have been loosely connected with ABL and even more loosely to South China presumably because of its geographical separation in the Northern Hemisphere. The separation of South China from the other megaunits is further supported by cluster analysis.

版权声明 本网站所有注明“来源:生物谷”或“来源:bioon”的文字、图片和音视频资料,版权均属于生物谷网站所有。非经授权,任何媒体、网站或个人不得转载,否则将追究法律责任。取得书面授权转载时,须注明“来源:生物谷”。其它来源的文章系转载文章,本网所有转载文章系出于传递更多信息之目的,转载内容不代表本站立场。不希望被转载的媒体或个人可与我们联系,我们将立即进行删除处理。

87%用户都在用生物谷APP 随时阅读、评论、分享交流 请扫描二维码下载->