Description and phylogenetic relationships of a new genus of octopus, Sasakiopus (Cephalopoda: Octopodidae), from the Bering Sea, with a redescription of Sasakiopus salebrosus (Sasaki, 1920)

摘要

A new genus of octopus, Sasakiopus, is erected for the species S. salebrosus (Sasaki, 1920) n. comb. Sasakiopus salebrosus is redescribed from the holotype and from new material recently collected in the eastern Bering Sea. Molecular phylogenetic analysis of one nuclear and three mitochondrial genes revealed that the new genus is the sister taxon of a clade containing the genera Benthoctopus and Vulcanoctopus. The clade containing Sasakiopus, Benthoctopus and Vulcanoctopus is the sister group of Enteroctopus. The genus Bathypolypus falls outside this clade. Sasakiopus differs from Bathypolypus and Enteroctopus by the shape of its ligula (simple in Sasakiopus and Benthoctopus, laminate in Bathypolypus and elongate in Enteroctopus), from Enteroctopus by the absence of enlarged suckers in mature male animals and from Benthoctopus by its skin sculpture and ability to ink.