Cantero Álvaro L Peña, Horton Tammy
Instituto Cavanilles de Biodiversidad y Biología Evolutiva / Departamento de Zoología, Universidad de Valencia, Valencia, Spain, Apdo. Correos 22085, 46071 Valencia, Spain..
Zootaxa. 2017 Nov 10;4347(1):1-30. doi: 10.11646/zootaxa.4347.1.1.
The deep-sea benthic hydroid fauna remains poorly known, in part because of less frequent sampling than the shelf fauna, in part owing to the immense study area, and partly also because available samples have been little studied by experts. In order to correct this, deep-sea benthic hydroid material from the modern Discovery Collections has been studied. Samples come from localities in the North-East Atlantic including the Porcupine Seabight, Porcupine Abyssal Plain, Rockall Trough, Rockall Bank, and the Mid-Atlantic Ridge. Sixteen species belonging to 12 families and 16 genera were found. Leptothecata are clearly dominant, being represented by 14 species; the remaining species belong to Anthoathecata. Lafoeidae and Tiarannidae are the most diverse families with three species each; the remaining families being represented by a single species. The low species diversity is remarkable at the generic level, with each genus being represented by a single species. Hydroid occurrence is low: twelve species were found in ≤ 9% of stations; Amphinema biscayana has the highest occurrence (27% of stations). Fifteen species were recorded in the Porcupine Seabight, two in the Rockall Trough, one at Rockall Bank, one on the Porcupine Abyssal Plain, and two at the Mid-Atlantic Ridge. The known bathymetric range for a third of the species is extended; the increase is particularly noteworthy in Amphinema biscayana, Acryptolaria crassicaulis, Clytia gigantea and Schizotricha profunda. Two distinct bathymetric groups are recognized: strictly deep-sea inhabitants and eurybathic species. Most species are globally distributed, some are widely distributed in the Atlantic, and others are limited to the North Atlantic or the Northeast Atlantic.
深海底栖水螅虫动物群仍然鲜为人知，部分原因是与陆架动物群相比采样频率较低，部分原因是研究区域广阔，还有部分原因是现有样本很少被专家研究。为了纠正这一情况，对现代发现收藏中的深海底栖水螅虫材料进行了研究。样本来自东北大西洋的多个地点，包括豪猪湾、豪猪深海平原、罗卡尔海槽、罗卡尔海台和大西洋中脊。共发现了属于12个科16个属的16个物种。软水母目明显占主导地位，有14个物种；其余物种属于花水母目。拉福水母科和细指水母科是种类最多的科，各有3个物种；其余科各有1个物种代表。在属的层面上，物种多样性较低，每个属只有1个物种代表。水螅虫的出现频率较低：12个物种出现在不到9%的站点；比斯开双瘤水母的出现频率最高（占站点的27%）。在豪猪湾记录到15个物种，在罗卡尔海槽记录到2个，在罗卡尔海台记录到1个，在豪猪深海平原记录到1个，在大西洋中脊记录到2个。三分之一物种的已知深度范围得到了扩展；在比斯开双瘤水母、粗茎隐囊水母、巨型棍螅和深海裂丝螅中，这种增加尤为显著。识别出两个不同的深度组：严格的深海栖息物种和广深性物种。大多数物种分布于全球，一些在大西洋广泛分布，另一些则局限于北大西洋或东北大西洋。
