Institut de Systématique, Evolution, Biodiversité, ISYEB - UMR 7205 CNRS MNHN UPMC EPHE, Muséum national d'Histoire naturelle, Sorbonne Universités, CP 50, 57 rue Cuvier, 75005, Paris, France.
Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix Marseille Univ., Univ. Avignon, CNRS, IRD, Centre IRD Nouméa, BP A5, 98848, Nouméa Cedex, New Caledonia.
Sci Rep. 2017 Jun 16;7(1):3705. doi: 10.1038/s41598-017-02964-x.
For a long time, New Caledonia was considered a continental island, a fragment of Gondwana harbouring old clades that originated by vicariance and so were thought to be locally ancient. Recent molecular phylogenetic studies dating diversification and geological data indicating important events of submergence during the Paleocene and Eocene (until 37 Ma) brought evidence to dismiss this old hypothesis. In spite of this, some authors still insist on the idea of a local permanence of a Gondwanan biota, justifying this assumption through a complex scenario of survival by hopping to and from nearby and now-vanished islands. Based on a comprehensive review of the literature, we found 40 studies dating regional clades of diverse organisms and we used them to test the hypothesis that New Caledonian and inclusive Pacific island clades are older than 37 Ma. The results of this meta-analysis provide strong evidence for refuting the hypothesis of a Gondwanan refuge with a biota that originated by vicariance. Only a few inclusive Pacific clades (6 out of 40) were older than the oldest existing island. We suggest that these clades could have extinct members either on vanished islands or nearby continents, emphasizing the role of dispersal and extinction in shaping the present-day biota.
长期以来，新喀里多尼亚被认为是一个大陆岛，是冈瓦纳大陆的一个碎片，拥有通过地理隔离起源的古老分支，因此被认为是当地的古老生物。最近的分子系统发育研究对多样化进行了年代测定，并结合地质数据表明，古新世和始新世（直到 3700 万年前）期间发生了重要的沉没事件，这些证据推翻了这一古老假说。尽管如此，一些作者仍然坚持冈瓦纳生物区系局部永久性的观点，通过从附近现已消失的岛屿跳跃来生存的复杂情景来证明这一假设。基于对文献的综合回顾，我们发现了 40 项研究，这些研究对不同生物的区域性分支进行了年代测定，我们利用这些研究来检验新喀里多尼亚和包括太平洋岛屿在内的分支的假设，即它们的起源早于 3700 万年前。这项荟萃分析的结果为反驳冈瓦纳避难所假说提供了有力的证据，该假说认为避难所内的生物是通过地理隔离起源的。只有少数包括太平洋岛屿在内的分支（40 个中的 6 个）比现存最古老的岛屿还要古老。我们认为，这些分支可能在已消失的岛屿或附近的大陆上灭绝了，这强调了扩散和灭绝在塑造当今生物区系方面的作用。
