Spio Fabricius, 1785

Bick, Andreas, 2011, Redescription of four species of Spio and Microspio (Polychaeta, Spionidae) from the Kuril Islands and Peter the Great Bay, northwest Pacific, Zootaxa 2968, pp. 39-56 : 40-41

Genus Spio Fabricius, 1785

Type species: Nereis filicornis Müller, 1776 Type locality: Iluilârssuk, near Frederikshaab (Paamiut), West Greenland

Synonym: Paraspio Czerniavsky, 1881 ; type species: Spio decoratus Bobretzky, 1870 , by monotypy. Euspio McIntosh, 1915 ; type species: Euspio mesnili McIntosh, 1915 .

Diagnosis. Prostomium usually anteriorly rounded or straight; branchiae present from chaetiger 1 to near posterior end; hooded hooks on middle and posterior neuropodia; metameric dorsal ciliated organs present; pygidium with 4 anal cirri.

Description. Prostomium anteriorly rounded, truncate or slightly incised, lacking frontal or lateral horns; eyes present or absent; digitiform occipital antenna absent, but posterior portion of prostomium may be raised or inflated. Nuchal organ with short median and long lateral ciliary bands, extending to chaetiger 2 or 3. Metameric dorsal ciliated organs present. Branchiae present from chaetiger 1, continuing almost throughout body, completely separate from or basally fused with notopodial lamella, often reduced in size on chaetiger 1. Notochaetae and anterior neurochaetae all capillaries; capillaries, hooded hooks and inferior sabre chaetae on middle and posterior chaetigers. Pygidium with 4 anal cirri.