Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France.
Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany; Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
Mol Phylogenet Evol. 2020 Jul;148:106816. doi: 10.1016/j.ympev.2020.106816. Epub 2020 Apr 11.
Invertebrates are exceptionally diverse, but many are in decline because of anthropogenic changes to their habitat. This situation is particularly problematic for taxa that are not well monitored or taxonomically poorly understood, because the lack of knowledge hampers conservation. Despite their important functional role in freshwater ecosystems, African bivalves of the family Unionidae remain poorly studied compared to their highly threatened relatives in Europe, the U.S.A. and Canada. To resolve relationships and to study diversification dynamics in space and time, we performed time-calibrated phylogenetic studies and biogeographical modeling on the unionids from the East African Rift System and surroundings, including representatives of all currently recognized Afrotropical genera except for Brazzaea (and Unio from southern Africa). Our analyses indicate that all sampled Afrotropical unionids belong to the tribe Coelaturini (subfamily Parreysiinae), as does the genus Moncetia from Lake Tanganyika, which is currently attributed to the family Iridinidae. Colonization of Africa from Eurasia by Parreysiinae occurred ~17 Ma ago, and the subsequent diversification of Coelaturini in Africa continued at a steady pace, although net diversification decreased over time as more niches and ecoregions became occupied. Clades in Coelaturini largely reflect drainage basins, with the oldest lineages and highest regional diversity occurring in Lake Tanganyika, followed by the Congo Basin watershed in general. The species assemblage of Lake Tanganyika reflects multiple independent events of colonization and intralacustrine diversification since the Late Miocene or Early Pliocene. The clades of other regions, including that containing the species from Lake Malawi, are comparatively young. Biogeographical analyses indicate that the colonization history was mainly driven by cladogenesis in sympatry, whereas few anagenetic events contributed to the modern distribution of Coelaturini. Ancestral range estimations demonstrate that Coelaturini originated in the Victoria and/or Tanganyika ecoregions, and that the Congo Basin played an essential role in the colonization of Africa by Coelaturini.
无脊椎动物种类繁多，但由于人类对其栖息地的改变，许多无脊椎动物的数量正在减少。这种情况对于那些没有得到很好监测或在分类学上了解甚少的分类群来说尤其成问题，因为缺乏知识会妨碍保护。尽管非洲淡水贝类在淡水生态系统中具有重要的功能作用，但与欧洲、美国和加拿大的高度受威胁的近亲相比，它们的研究仍然很少。为了解决关系，并研究空间和时间上的多样化动态，我们对东非裂谷系统及其周边地区的联合类进行了时间校准的系统发育研究和生物地理建模，包括除 Brazzaea（以及来自南部非洲的 Unio）以外的所有目前公认的非洲热带属的代表。我们的分析表明，所有采样的非洲热带联合类都属于 Coelaturini 部落（Parreysiinae 亚科），坦噶尼喀湖的 Moncetia 属也是如此，该属目前属于 Iridinidae 科。Parreysiinae 从欧亚大陆向非洲的殖民发生在约 1700 万年前，随后 Coelaturini 在非洲的多样化继续稳步进行，尽管随着更多的生态位和生态区被占据，净多样化随着时间的推移而减少。Coelaturini 中的进化枝在很大程度上反映了流域，最古老的谱系和最高的区域多样性发生在坦噶尼喀湖，其次是一般的刚果盆地流域。坦噶尼喀湖的物种组合反映了自上新世或更新世早期以来多次独立的殖民和湖泊内多样化事件。包括马拉维湖物种在内的其他地区的进化枝相对较年轻。生物地理分析表明，殖民历史主要是由同域的分支进化驱动的，而很少有新进化事件有助于 Coelaturini 的现代分布。祖先范围估计表明，Coelaturini 起源于维多利亚和/或坦噶尼喀生态区，刚果盆地在 Coelaturini 对非洲的殖民化中发挥了重要作用。
