创新是进化成功和进入新生态系统的关键。1物种自由漂浮在海洋表面,称为专性神经(也称为pleuston,这里简称为neuston),包括来自不同进化谱系的高度专业化的类群,这些进化谱系进化了漂浮形态。21958年,苏联科学家,A.I.Savilov,3指出,漂浮的动物物种来自底栖祖先,而不是来自邻近中上层带的物种,漂浮形态与底栖附着结构同源。为了检验萨维洛夫的假设,我们构建了所有主要漂浮群体的分子系统发育和祖先状态,这些群体有分子数据。我们的结果表明,所检查的五个分支中有四个直接来自与底物相连的祖先,尽管该底物不一定是底栖动物,正如Savilov所说,而是包括了表观生物和漂流祖先。尽管它们的进化起源不同,漂浮的动物使用气体捕获机制留在表面,4,5,6和许多这些气体捕获结构似乎与衬底附着结构是同源的。我们还重建了漂浮软体动物及其姐妹物种的营养习性,揭示了进入海洋表面生态系统后,猎物偏好保持保守。海洋表面的定殖似乎是通过从海底开始的连续进化步骤而发生的。我们的结果表明,这些步骤通常包括通过表观生物(物种附着于其他生物体)或漂流(物种附着于漂浮碎片)习惯的过渡。水-空气界面,尽管其独特的属性,may,在某些方面,只是另一个基底。
Innovation is a key to evolutionary success and entrance into novel ecosystems.1 Species that float freely at the ocean\'s surface, termed obligate neuston (also called pleuston, here referred to simply as neuston), include highly specialized taxa from distinct evolutionary lineages that evolved floating morphologies.2 In 1958, Soviet scientist, A.I. Savilov,3 stated that floating animal species are derived from benthic ancestors, rather than species from the adjacent pelagic zone, and that floating morphologies are homologous to benthic attachment structures. To test Savilov\'s hypothesis, we constructed molecular phylogenies and ancestral states for all major floating groups for which molecular data were available. Our results reveal that four of the five clades examined arose directly from a substrate-attached ancestor, although that substrate was not necessarily the benthos, as Savilov stated, and instead included epibiotic and rafting ancestors. Despite their diverse evolutionary origins, floating animals use gas-trapping mechanisms to remain at the surface,4,5,6 and many of these gas-trapping structures appear to be homologous to substrate attachment structures. We also reconstruct the trophic habits of floating mollusks and their sister species, revealing that prey preference remains conserved upon entering the ocean\'s surface ecosystem. Colonization of the ocean\'s surface seems to have occurred through successive evolutionary steps from the seafloor. Our results suggest that these steps often included transitions through epibiotic (where species attach to other living organisms) or rafting (where species attach to floating debris) habits. The water-air interface, despite its unique properties, may, in some ways, be just another substrate.