A new southern record of the holopelagic annelid Poeobius meseres Heath, 1930 (Flabelligeridae)

The unusual holopelagic annelid Poeobius meseres Heath, 1930 (Flabelligeridae) was first collected from Monterey Bay, California, and has been subsequently recorded across the northern Pacific from Japan to the Gulf of California. Rare occurrences in the eastern tropical Pacific have extended as far as 7° S off Peru.Using molecular phylogenetic analysis of a newly collected specimen from the Salas y Gómez Ridge off Chile, we extend the known geographic range of P. meseres southward by 2040 km. This subtropical specimen showed higher genetic similarity to a specimen from the type locality (<1.5% pairwise COI distance) than to representatives from the Aleutian Islands and Japan (5-6%), establishing the first genetically confirmed occurrence of this species in the southern hemisphere. The latitudinal range of P. meseres encompasses the sole collection locality, off Ecuador, of Enigma terwielii Betrem, 1925, a pelagic annelid which has been compared to P. meseres, but is indeterminable due to an inadequate description. We therefore suggest that the earlier sole record of E. terwielii may have been an occurrence of what is known now as P. meseres.

不寻常的全水层环节动物Poeobius meseres Heath, 1930（拟球虫科）最初采集于加利福尼亚州的蒙特雷湾，其后在从日本至加利福尼亚湾的北太平洋区域均有记录。在东热带太平洋的罕见出现已延伸至秘鲁海岸7°S。通过从智利萨拉斯与戈梅斯海脊新采集的样本进行分子系统发育分析，我们扩展了P. meseres已知地理分布范围向南延伸了2040公里。这一亚热带样本与模式标本的遗传相似度较高（成对COI距离小于1.5%），相较于阿留申群岛和日本的代表样本（5-6%），确立了该物种在南半球的首次遗传学确认出现。P. meseres的纬度分布范围包括了唯一采集地，即厄瓜多尔海岸外的Enigma terwielii Betrem, 1925（一种浮游环节动物，曾与P. meseres进行比较，但由于描述不足而无法确定）。因此，我们推测早期关于E. terwielii的唯一记录可能实际上是现知P. meseres的一种出现。