新種の海綿状ヒトデ、sp.(Asteroidea: Brisingida: Brisingidae) の新種

A new sponge-associated starfish, sp. nov. (Asteroidea: Brisingida: Brisingidae), from the northwestern Pacific seamounts.

• Ruiyan Zhang
• Yadong Zhou
• Ning Xiao
• Chunsheng Wang

抄録

海山は、様々な種類の生息地や動物相のための貯水地として機能する重要な深海の実体である。太平洋北西部の海山地域での中国のクルーズでは、水深1,458-2,125 mでBrisingida目ヒトデの新種が発見された。この新種は，すべての標本が六角海綿に付着していることが観察されたことから，この2種の近縁種である可能性が示唆された。Brisingida属の系統解析を行い，新種のほか，cf. (Fisher, 1906), cf. Sladen, 1889および2種を加えた系統解析を行った。系統樹は種との関係よりも種との関係を示唆しているが，これは形態学的分類学とは矛盾している。本研究は、新種の形態学的・生態学的特徴を明らかにし、今後のブリジンゲダの系統樹研究に新たなデータを提供するものである。

Seamounts are important deep ocean entities that serve as reservoirs for varied types of habitats and fauna. During the Chinese cruises in the northwestern Pacific seamount areas, a new starfish species of order Brisingida, , was found at 1,458-2,125 m depth. All specimens of the new species were observed in situ attaching on hexactinellid sponges, suggesting a possible close relationship between the two taxa. is the second known species of the genus, characterized by the abutting plates in the intercostal integument, separated first pair of adambulacral plates and densely distributed proximal spines. Phylogenetic analyses were conducted for order Brisingida to incorporate the new species as well as cf. (Fisher, 1906), cf. Sladen, 1889 and two spp., for which we present the molecular data for the first time. Phylogenetic trees suggest a close relationship between with species rather than with species, which is inconsistent with morphological taxonomy. This study highlights the distinct morphological and ecological characters of the new species and provides new data for future investigation on Brisingida phylogeny.

©2020 Zhang et al.