IMBE (UMR CNRS 7263, IRD 237) Evolution Génome Environnement, Aix-Marseille Université, Marseille, France.
PLoS One. 2013 Apr 12;8(4):e59439. doi: 10.1371/journal.pone.0059439. Print 2013.
Thecosomata is a marine zooplankton group, which played an important role in the carbonate cycle in oceans due to their shell composition. So far, there is important discrepancy between the previous morphological-based taxonomies, and subsequently the evolutionary history of Thecosomata. In this study, the remarkable planktonic sampling of TARA Oceans expedition associated with a set of various other missions allowed us to assess the phylogenetic relationships of Thecosomata using morphological and molecular data (28 S and COI genes). The two gene trees showed incongruities (e.g. Hyalocylis, Cavolinia), and high congruence between morphological and 28S trees (e.g. monophyly of Euthecosomata). The monophyly of straight shell species led us to reviving the Orthoconcha, and the split of Limacinidae led us to the revival of Embolus inflata replacing Limacina inflata. The results also jeopardized the Euthecosomata families that are based on plesiomorphic character state as in the case for Creseidae which was not a monophyletic group. Divergence times were also estimated, and suggested that the evolutionary history of Thecosomata was characterized by four major diversifying events. By bringing the knowledge of palaeontology, we propose a new evolutionary scenario for which macro-evolution implying morphological innovations were rhythmed by climatic changes and associated species turn-over that spread from the Eocene to Miocene, and were shaped principally by predation and shell buoyancy.
有孔虫是海洋浮游动物群的一个分支，由于其壳的成分，它们在海洋碳循环中起着重要作用。迄今为止，以前基于形态的分类学和随后的有孔虫进化历史之间存在重要差异。在这项研究中，TARA 海洋考察队的显著浮游生物采样与一系列其他任务相结合，使我们能够使用形态学和分子数据（28S 和 COI 基因）评估有孔虫的系统发育关系。这两个基因树显示出不一致（例如，Hyalocylis、Cavolinia），而形态学和 28S 树之间具有高度一致性（例如，Euthecosomata 的单系性）。直壳物种的单系性导致我们重新恢复了 Orthoconcha，并且 Limacinidae 的分裂导致我们重新恢复了 Embolus inflata 以取代 Limacina inflata。研究结果还危及到基于原始特征状态的 Euthecosomata 科，例如 Creseidae 就不是一个单系群。还估计了分歧时间，表明有孔虫的进化历史具有四个主要的多样化事件。通过引入古生物学知识，我们提出了一个新的进化情景，其中宏观进化意味着形态创新受到气候变化和相关物种更替的节奏影响，这些更替从始新世到中新世传播，并主要由捕食和壳浮力塑造。
