Bilton David T
Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK..
Zootaxa. 2018 Feb 7;4378(2):284-288. doi: 10.11646/zootaxa.4378.2.9.
Parhydraena d'Orchymont, 1937 currently includes 19 species, 17 of which are endemic to South Africa (Perkins 2009; Bilton 2014). Most species of the genus are fully aquatic, but a few, together with members of other genera of Parhydraenini, occupy moist habitats rich in organic debris (Perkins 2009). These so-called humicolous habitats (Perkins Balfour-Browne 1994) occur both beside water and elsewhere, and have been colonised a number of times by primarily aquatic hydraenid lineages, particularly in Africa and Australasia (e.g. Perkins Balfour-Browne 1994; Perkins 2004a, 2004b; Perkins 2009; Hernando Ribera 2017). Within Parhydraena the toro group (sensu Perkins 2009) comprises four (sub)humicolous species which share a broad habitus, a marked constriction between the pronotum and elytral shoulders, and short legs and maxillary palpi. Whilst phylogenetic relationships within Parhydraena remain unclear in the absence of molecular data, the toro group as currently defined may not be monophyletic, given the differences in aedeagal anatomy observed amongst its members (see Perkins 2009). The most morphologically divergent species described to date is P. toro Perkins, 2009, whose simplified aedeagal anatomy differs considerably from all other known members of the genus. P. toro appears to be narrowly endemic to the inselberg of Table Mountain and surroundings, occurring in damp litter in Afromontane forests and beside seepages and streams (Perkins 2009; DTB pers. obs.). Here I describe a new species from a cool, high-altitude gully in the western end of Hex River Mountains, which closely resembles P. toro in external and aedeagal morphology and shares its humicolous microhabitat.
1937年命名的Parhydraena d'Orchymont目前包含19个物种，其中17个为南非特有种（珀金斯，2009年；比尔顿，2014年）。该属的大多数物种完全水生，但有少数物种，与Parhydraenini族其他属的成员一起，栖息在富含有机碎屑的潮湿生境中（珀金斯，2009年）。这些所谓的喜湿生境（珀金斯和巴尔弗-布朗，1994年）既出现在水边，也出现在其他地方，并且已经被主要水生的沼甲科谱系多次占据，特别是在非洲和澳大拉西亚（例如珀金斯和巴尔弗-布朗，1994年；珀金斯，2004a、2004b；珀金斯，2009年；埃尔南多和里韦拉，2017年）。在Parhydraena属中，toro组（按照珀金斯2009年的定义）包含四个喜湿物种，它们具有相似的总体形态、前胸背板和鞘翅肩部之间明显的缢缩，以及短腿和下颚须。虽然在缺乏分子数据的情况下，Parhydraena属内的系统发育关系仍不清楚，但鉴于在其成员中观察到的阳茎解剖结构差异，目前定义的toro组可能不是单系的（见珀金斯，2009年）。迄今为止描述的形态差异最大的物种是2009年命名的P. toro Perkins，其简化的阳茎解剖结构与该属所有其他已知成员有很大不同。P. toro似乎仅局限于桌山及其周边的inselberg，出现在非洲山地森林的潮湿枯枝落叶层以及渗水处和溪流旁（珀金斯，2009年；DTB个人观察）。在此，我描述一种来自赫克斯河山山脉西端一个凉爽、高海拔沟壑的新物种，它在外部形态和阳茎形态上与P. toro非常相似，并且共享其喜湿微生境。
