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 Paraprionospio Caullery, 1914 Larval diagnosis. Overall shape long and slender, large in size (> 4 mm) and number of chaetigers (> 35 chaetigers) at metamorphosis. Prostomium rounded. Lateral parts of peristomium moderately demarcated from prostomium. Two pairs of red or dark red eyes present. Pigmentation absent except eyes and some reddish pigmentation on pygidium. Nototrochs absent. Gastrotrochs occur in all chaetigers from chaetiger II onwards. Branchiae well developed and elongated in late larvae. Long larval chaetae may be absent in chaetiger II ( Berkeley and Berkeley 1961 , as Prionospio ; Carrasco 1976 ; Yokoyama 1981 , 1996 ; Blake and Arnofsky 1999 ).