Hookabe Natsumi, Jimi Naoto, Fujimoto Shinta, Kajihara Hiroshi
Research Institute for Global Change (RIGC), JAMSTEC, Yokosuka, Kanagawa 237-0061, Japan.
Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, Mie 517-0004, Japan.
R Soc Open Sci. 2024 Jun 19;11(6). doi: 10.1098/rsos.231782. eCollection 2024 Jun.
Polychaetes are typically found in marine environments with limited species adapting to semi-terrestrial habitats. The genus comprises interstitial polychaetes dwelling in sandy beach areas around or above the high-water line. Based on molecular data, previous studies suggested the presence of multiple cryptic species in some different localities in the world lumped together as . In Japan, reports on were scarce, with only one species having been documented 40 years ago at Ishikari Beach in Hokkaido by the name of . We revisited these earlier findings and uncovered the presence of two distinct species in . One of these species is herein named sp. nov., while the other corresponds to , originally described from the Russian Far East. sp. nov. possesses a chaetal pattern similar to that of , and but can be distinguished from the congeners by two characters: a slightly forked pygidium and forked chaetae consisting of two teeth and two outer prongs. Our multi-locus phylogenetic analysis showed close relationships across the Pacific Ocean in two separated lineages in the genus, suggesting ancient dispersal or allopatric speciation after vicariance events.
多毛纲动物通常见于海洋环境，只有少数物种适应半陆地栖息地。该属包括栖息在高潮线附近或以上沙滩区域的间隙多毛纲动物。基于分子数据，先前的研究表明，在世界上一些不同地区存在多个隐存种，它们被归为同一类。在日本，关于该属的报道很少，40年前在北海道石狩湾海滩仅记录了一个物种，名为[具体名称]。我们重新审视了这些早期发现，发现该属存在两个不同的物种。其中一个物种在此被命名为[新物种名称] sp. nov.，另一个与最初在俄罗斯远东地区描述的[物种名称]相对应。[新物种名称] sp. nov.具有与[其他相关物种名称]、[其他相关物种名称]和[其他相关物种名称]相似的刚毛模式，但可通过两个特征与同属其他物种区分开来：尾节略呈叉状，以及由两个齿和两个外叉组成的叉状刚毛。我们的多位点系统发育分析表明，该属在太平洋两岸的两个独立谱系中存在密切关系，这表明在地理隔离事件后存在古老的扩散或异域物种形成。
