Gymnonereis

Prostomium with anterior margin indented. Maxillary ring of pharynx without papillae. Maxillary ring of pharynx without paragnaths. Oral ring papillae present; solitary. Area V papillae present; VI papillae present; VII-VIII papillae present. Oral ring paragnaths absent. Transverse dorsal lamellae absent, or present. Dorsal notopodial ligule not markedly elongate on posterior chaetigers. Not markedly broader on posterior chaetigers. Dorsal notopodial ligule markedly reduced on posterior chaetigers (but cirrophore of dorsal cirrus is expanded and looks like an expanded notopodial lobe unless progressive change is noted over many chaetigers). Prechaetal notopodial lobe present. Dorsal cirrus not terminally attached to dorsal notopodial ligule on posterior chaetigers. Neuropodial postchaetal lobe present, at least on some anterior chaetigers. Ventral neuropodial ligule on posterior chaetigers similar to length of acicular neuropodial ligule, or reduced, up to half length of acicular neuropodial ligule. Ventral cirri paired. Notopodial homogomph spinigers present, or absent; sesquigomph spinigers present. Notopodial homogomph falcigers absent. Neuropodial dorsal fascicle fused falcigers absent.

Unless stated otherwise in the below description, the following character states are implicit for all Nereididae species: Maxillary ring of pharynx without papillae. Maxillary ring divided into discrete Areas. Maxillary ring of pharynx with paragnaths; paragnaths arranged in discrete areas; Areas II, III and IV paragnaths not in regular comb-like rows (but may be arranged in irregular rows). Area I minute rod-like paragnaths in a compact cluster absent; II minute rod-like paragnaths in a compact cluster absent; pectinate paragnaths absent; minute rod-like paragnaths in a compact cluster absent; pectinate paragnaths absent; minute rod-like paragnaths in a compact cluster absent; smooth bar-like paragnaths absent; pectinate paragnaths absent. Oral ring papillae absent. Ring of oral ring paragnaths present as irregular rows, not crown-shaped. Smooth bars absent; pectinate rows absent; pectinate paragnaths absent; arranged in one or more irregular lines forming a continuous band; Area VII-VIII paragnaths similar in size, or irregular mix of large and small paragnaths in a single band. Transverse dorsal lamellae absent. Dorsal notopodial ligule not markedly elongate on posterior chaetigers. Not markedly broader on posterior chaetigers. Ventral cirri single.

Distinguished from other Nereididae genera by: Dorsal cirri paired (= accessory dorsal cirri present)