PDF(Pubmed)
Abstract：
During the present study, the evolutionary relationship within a clade of mountain clade of freshwater crabs (Potamonautes) was examined using mtDNA sequence data for species from the Cape Fold Mountain (CFM) and Great Escarpment (Drakensberg Mountain range). We undertook phylogenetic analyses, divergence time estimation, and an ancestral area reconstruction to explore the period of cladogenesis and understand the biogeographic history in this high-altitude clade. Furthermore, we applied four species delimitation methods using ASAP, bPTP, bGMYC, and STACEY on the latter clade. Bayesian phylogenetic analyses retrieved a monophyletic freshwater crab clade comprised of two major sister clades, one comprised of the Cape Fold (clade A) and two comprised of Drakensberg Mountains (clade B) species. Divergence time estimation indicated that the two clades underwent Mio/Pliocene cladogenesis. Within the CFM clade (A), P. amathole (Amathola Mountains) was sister to P. parvispina (Cederberg and Kouebokkeveld Mountains) and the latter species were sister to P. parvicorpus (Cape Peninsula, Jonkershoek, and Helderberg Mountains) sister to P. tuerkayi (Overberg Mountains) and P. brincki (Hottentots Holland Mountains). Within the Drakensberg Mountain clade (B), we observed in situ diversification. Specimens from the southcentral Drakensberg Mountains (Dargle Forest, Injasuti, Karkloof, and Impendle) represent a new undescribed lineage Potamonautes sp. nov. 1. The second clade from the northern Drakensberg, representing P. clarus, was sister to a central Drakensberg Mountain clade that comprised P. depressus that was in turn sister to P. baziya from the Eastern Cape Province. The application of species delimitation methods generally overestimated the number of species. The biogeographic analyses indicated that the Eastern Cape Province is the most likely ancestral range area. Ecological niche modelling of representative species in clades A (Cape Fold Mountains) and B (Drakensberg Mountains) demonstrated that temperature and rainfall were the major abiotic drivers that differentiated the two clades. Our data favours the mountain gradient speciation hypothesis.
摘要：
在本研究中,使用来自CapeFold山（CFM）和大悬崖（Drakensberg山脉）的物种的mtDNA序列数据，检查了淡水蟹（Potamonautes）山枝中的进化关系。我们进行了系统发育分析，发散时间估计，以及祖先地区的重建，以探索该高原进化枝的形成时期并了解其生物地理历史。此外，我们使用ASAP应用了四种物种划界方法，bPTP,bGMYC,和后一种进化枝的STACEY。贝叶斯系统发育分析检索到了由两个主要姐妹进化枝组成的单系淡水蟹进化枝，一个由CapeFold（进化枝A）组成，两个由Drakensberg山脉（进化枝B）组成。发散时间估计表明，这两个进化枝经历了Mio/上新世枝层形成。在CFM进化枝（A）内，P.amathole（Amathola山脉）是P.parvispina（Cederberg和Kouebokkeveld山脉）的姐妹，后者是P.parvicorpus（开普半岛，Jonkershoek,和Helderberg山脉）的姐姐P.tuerkayi（奥弗伯格山脉）和P.brincki（霍滕托特荷兰山脉）。在Drakensberg山进化枝（B）内，我们观察到原位多样化。来自德拉肯斯堡山脉中南部的标本（DargleForest，因贾苏提,Karkloof,和Impendle）代表一个新的未描述的谱系Potamonautessp。11月。1.来自北部德拉肯斯堡的第二个进化枝，代表P.Clarus,是中央德拉肯斯堡山脉进化枝的姐妹，该进化枝包括P.depressus，而P.depressus又是来自东开普省的P.baziya的姐妹。物种定界方法的应用普遍高估了物种的数量。生物地理分析表明，东开普省是最有可能的祖先地区。进化枝A（CapeFoldMountains）和进化枝B（DrakensbergMountains）的代表物种的生态位模型表明，温度和降雨是区分这两个进化枝的主要非生物驱动因素。我们的数据支持山脉梯度形态假说。
