Two new species of pygmy octopuses (Cephalopoda: Octopodidae) from deep water off the Ryukyu Archipelago, southern Japan

摘要

Two new species of pygmy octopuses are described from upper bathyal waters (350-370 m) around the Ryukyu Archipelago. Bathypolypus rubrostictus n. sp. is characterized by its small body (20 mm ML), short arms ( 2-2.5xML), no enlarged suckers, large spoon-shaped ligula with five deep transverse laminae and large round calamus. There are numerous small brownish-red spots on the dorsal surface of the mantle, which is smooth, without papillae, and webs are pale reddish brown. Octopus diminutus n. sp. ischaracterized by its diminutive adult body size (13-17 mm ML), short arms (2-3xML), enlarged suckers on the arms of the male, very large pointed calamus, pale brown body colour, and elongate compound superocular papillae. The generic placement of the two species and taxonomic definitions of the genera Octopus and Bathypolypus are discussed.