Amphipods in a Greek cave with sulphidic and non-sulphidic water: phylogenetically clustered and ecologically divergent

We characterized taxonomically, ecologically, and phylogenetically the amphipod community of Melissotrypa Cave (Central Greece), which comprises both freshwater and sulphidic lakes. We found four amphipod species: <i>Niphargus jovanovici</i>, <i>Niphargus lindbergi</i>, <i>Niphargus gammariformis</i> sp. nov. and an unknown species of <i>Bogidiella.</i> The three <i>Niphargus</i> species form a well-supported monophylum but differ in their ecology and morphology: <i>N. jovanovici</i> is a small and slender species inhabiting small freshwater voids, <i>N. lindbergi</i> is a large and stout species living in freshwater lakes, whereas <i>N. gammariformis</i> sp. nov. is a small and stout species found predominantly in a sulphidic lake. Available evidence suggests that diversification may have happened in a geographically restricted area and was driven by ecological differentiation. <i>Niphargus gammariformis</i> sp. nov. shows morphological convergences in diagnostic traits with two species hitherto classified into the genus <i>Pontoniphargus.</i> As molecular phylogenies show <i>Pontoniphargus</i> nested within <i>Niphargus</i>, we synonymize here <i>Pontoniphargus</i> with <i>Niphargus</i>. The species originally named <i>Pontoniphargus ruffoi</i> needed to be renamed into <i>Niphargus pontoruffoi.</i> http://www.zoobank.org/urn:lsid:zoobank.org:pub:4F5EED3B-DEB4-4402-BCE8-6AE2B65CCC3A

本研究从分类学、生态学与系统发育学维度，对希腊中部梅利斯特里帕洞穴（Melissotrypa Cave）内的端足类（Amphipoda）群落开展了系统表征；该洞穴同时包含淡水湖与硫化湖两种生境。本次研究共记录到4种端足类：约氏泥钩虾（*Niphargus jovanovici*）、林氏泥钩虾（*Niphargus lindbergi*）、新种伽马形泥钩虾（*Niphargus gammariformis* sp. nov.）以及1个待定的博氏钩虾属（*Bogidiella*）未知物种。上述3种泥钩虾属（*Niphargus*）物种构成了一个支持度极高的单系群，但在生态位与形态特征上存在显著分化：约氏泥钩虾体型小巧纤细，栖息于小型淡水孔隙生境；林氏泥钩虾体型粗壮硕大，营淡水湖泊生活；而新种伽马形泥钩虾（*N. gammariformis* sp. nov.）则体型小巧粗壮，主要发现于硫化湖生境中。现有证据表明，该类群的物种分化可能发生在地理受限的区域内，且由生态位分化所驱动。新种伽马形泥钩虾（*Niphargus gammariformis* sp. nov.）的分类诊断性状，与此前被归入庞托尼钩虾属（*Pontoniphargus*）的2个物种存在形态趋同现象。分子系统发育分析结果显示，庞托尼钩虾属（*Pontoniphargus*）嵌套于泥钩虾属（*Niphargus*）内部，因此本研究将庞托尼钩虾属归并入泥钩虾属，作为其同物异名。原命名为罗氏庞托尼钩虾（*Pontoniphargus ruffoi*）的物种，现更名为罗氏泥钩虾（*Niphargus pontoruffoi*）。http://www.zoobank.org/urn:lsid:zoobank.org:pub:4F5EED3B-DEB4-4402-BCE8-6AE2B65CCC3A