Molecular identification and larval morphology of spionid polychaetes (Annelida, Spionidae) from northeastern Japan Author Abe, Hirokazu https://orcid.org/0000-0002-7753-9368 Department of Biology, Center for Liberal Arts & Sciences, Iwate Medical University, Idaidori 1 - 1 - 1, Yahaba-cho, Shiwa-gun, Iwate 028 - 3694, Japan habe@iwate-med.ac.jp Author Sato-Okoshi, Waka Laboratory of Biological Oceanography, Graduate School of Agricultural Science, Tohoku University, Aramaki-Aza-Aoba 468 - 1, Aoba-ku, Sendai 980 - 8572, Japan text ZooKeys 2021 2021-02-04 1015 1 86 http://dx.doi.org/10.3897/zookeys.1015.54387 journal article http://dx.doi.org/10.3897/zookeys.1015.54387 1313-2970-1015-1 F6BD92139DB74564AA003C61B2F43B2D AF1641758561525C8D40BBF3F895FA8A Genus Rhynchospio Hartman, 1936 Larval diagnosis. Overall body shape short and thick. Prostomium broad and straight or slightly notched anteriorly. Lateral parts of peristomium clearly demarcated from prostomium. Palps attached to outer end of lateral parts of peristomium. Two pairs of red or black eyes present. Faint yellow pigment may be present in anterior part of prostomium and posterior part of pygidium. In late larvae, pair of prominent antero-lateral processes on prostomium developed. Melanophore absent, black or yellowish pigmentation occur in some species. Nototrochs weakly developed, occur in all chaetigers except first chaetiger. Gastrotrochs occur regularly in every other chaetiger from chaetiger III onwards ( Carrasco 1976 ; Radashevsky 2007 ).