Department of Biology and Biotechnologies C Darwin, Sapienza Rome University, I-00161 Rome, Italy.
Mol Phylogenet Evol. 2011 Dec;61(3):772-83. doi: 10.1016/j.ympev.2011.07.020. Epub 2011 Aug 10.
Hydraena is the largest genus within the water beetle family Hydraenidae, with ca. 1000 species distributed worldwide. Within this large genus some monophyletic groups of species are recognised, among them the "Haenydra" lineage, including ca. 90 species distributed in the western Palaearctic from the Iberian peninsula to Iran. Species of "Haenydra" have often very restricted distributions, and are typical of clean small rivers and streams. We obtained ca. 2.5Kb of mitochondrial and nuclear protein-code and ribosomal markers of 101 specimens of 69 species of "Haenydra", and used Bayesian and Maximum Likelihood phylogenetic methods to reconstruct their phylogeny and diversification history. We found a derived phylogenetic position of the "Haenydra" lineage within the genus Hydraena, as sister to the species of the Hydraenabisulcata group. Within "Haenydra" three main lineages were recognised, with poorly resolved relationships among them: the Hydraena iberica, Hydraena gracilis and Hydraena dentipes lineages, the former restricted to the Iberian peninsula but the latter two distributed through the whole north-Mediterranean area. A Bayesian relaxed molecular clock approach using a combined mitochondrial rate of 2% divergence per MY estimated the origin of "Haenydra" in the Tortonian, ca. 8Mya, and the main diversification and the origin of most extant species in the Pliocene and Pleistocene. We did not found evidence of a phylogenetic connection between the western and eastern species that could be traced to the Messinian salinity crisis, with dispersal only at small geographical scales (e.g. the colonisation of Corsica and Sardinia from NW Italy and SW France). The H. gracilis and H. iberica lineages were estimated to have diversified under a pure birth model with a speciation rate of 0.64 and 0.23 species/MY respectively, while the H. dentipes lineage was estimated to have a decreasing diversification rate with time, with an average rate of 0.29 sp/MY.
水龟甲科 Hydraenidae 是龟甲科中最大的属，约有 1000 种分布于世界各地。在这个大属中，有些单系种群被识别出来，其中包括“Haenydra”谱系，包括约 90 种分布于从伊比利亚半岛到伊朗的西古北区。“Haenydra”的物种分布通常非常有限，是清洁的小河和溪流的典型代表。我们获得了 101 个 69 种“Haenydra”标本的约 2.5Kb 的线粒体和核蛋白编码和核糖体标记物，并使用贝叶斯和最大似然系统发育方法重建了它们的系统发育和多样化历史。我们发现“Haenydra”谱系在 Hydraena 属内具有衍生的系统发育位置，是 Hydraenabisulcata 组物种的姐妹群。在“Haenydra”中，识别出了三个主要的谱系，它们之间的关系不太明确：Hydraena iberica、Hydraena gracilis 和 Hydraena dentipes 谱系，前者仅限于伊比利亚半岛，但后两者分布于整个北地中海地区。使用线粒体的综合速率为 2%的贝叶斯松弛分子钟方法估计了“Haenydra”的起源于托尔顿期，约 800 万年前，以及主要的多样化和大多数现存物种的起源于上新世和更新世。我们没有发现西部和东部物种之间存在可以追溯到墨西拿盐度危机的系统发育联系的证据，只有在小地理尺度上的扩散（例如从意大利西北部和法国西南部到科西嘉岛和撒丁岛的殖民）。估计 H. gracilis 和 H. iberica 谱系的多样化是在纯出生率模型下进行的，分别具有 0.64 和 0.23 种/MY 的种形成率，而 H. dentipes 谱系的多样化率随时间呈下降趋势，平均速率为 0.29 sp/MY。
