Laboratório de Genética e Ecologia Animal, Departamento de Biologia Geral, Universidade Estadual de Londrina, Londrina, PR, Brazil.
Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America.
PLoS One. 2018 Jul 5;13(7):e0199963. doi: 10.1371/journal.pone.0199963. eCollection 2018.
The southern region of Brazil is characterized by high species diversity and endemism of freshwater fishes distributed across geographically isolated river basins. Microglanis cottoides has a widespread range across these river basins and occurs in sympatry with other endemic species of the genus (e.g. M. cibelae, M. eurystoma, and M. malabarbai). Herein we tested the monophyly of M. cottoides and presented for the first time information about the molecular phylogeny of species in the genus. The results suggest that M. cottoides currently forms a non-monophyletic group which includes populations endemic to the Uruguay River basin that are more closely related to M. malabarbai, and excludes M. cibelae, found to be nested within M. cottoides. Based on an integrative approach using morphological and molecular data, we propose M. cibelae as a junior synonym of M. cottoides, and the populations of the Uruguay River basin previously assigned to M. cottoides in fact belong to M. malabarbai. Our molecular phylogeny shows that M. cottoides is sister to M. parahybae, which is also a coastal species, and M. malabarbai is sister of M. garavelloi, both endemic to inland river basins. The time-calibrated phylogeny indicates that the separation between inland and the coastal clades occurred in the Tertiary period, and that the species within the coastal basins diverged in the Pliocene, which overlaps with the diversification times estimated for the two inland species as well. This pattern of diversification corroborates some previous studies with other fishes from the same region.
巴西南部地区的特点是具有高度的物种多样性和淡水鱼类的特有性，这些鱼类分布在地理上相互隔离的河流流域中。Microglanis cottoides 广泛分布于这些河流流域中，与该属的其他特有种（例如 M. cibelae、M. eurystoma 和 M. malabarbai）共存。在此，我们测试了 M. cottoides 的单系性，并首次提供了该属物种的分子系统发育信息。结果表明，M. cottoides 目前形成了一个非单系群体，其中包括乌拉圭河流域的特有种群，这些种群与 M. malabarbai 的亲缘关系更为密切，而不包括 M. cibelae，后者被发现嵌套在 M. cottoides 中。基于使用形态学和分子数据的综合方法，我们提议将 M. cibelae 作为 M. cottoides 的次同物，而以前分配给 M. cottoides 的乌拉圭河流域的种群实际上属于 M. malabarbai。我们的分子系统发育表明，M. cottoides 与也是沿海物种的 M. parahybae 为姐妹群，而 M. malabarbai 则与仅在内陆河流流域的 M. garavelloi 为姐妹群。时间校准的系统发育表明，内陆和沿海分支之间的分离发生在第三纪，而沿海流域内的物种在更新世分化，这与估计的两个内陆物种的多样化时间重叠。这种多样化模式与来自同一地区的其他鱼类的一些先前研究相吻合。
