Hymenocephalus

Mcmillan, Peter & Iwamoto, Tomio, 2014, Descriptions of four species of grenadier fishes of the genera Hymenocephalus and Hymenogadus (Teleostei, Gadiformes, Macrouridae) from the New Zealand region and Tasman Sea, including two new species of Hymenocephalus, Zootaxa 3856 (1), pp. 117-134 : 132

Key to the known species of Hymenocephalus (3) and Hymenogadus (1) from New Zealand

1 First dorsal fin with smooth spinous second ray.............................................................. 2

-. First dorsal fin with weakly serrated spinous second ray.................. Hymenogadus gracilis Slender membranehead

2 Chin barbel present; 8 pelvic fin rays........................ Hymenocephalus maculicaudus Spottytail membranehead

-. Chin barbel absent; 11–14 pelvic fin rays.................................................................. 3

3 Head and body uniformly dark brown to blackish; orbit diameter small, 20–33% HL, suborbital width 23–28% HL......................................................................... Hymenocephalus fuscus Black membranehead

-. Head and body pale greyish to brown overall, with prominent lateral (silvery when fresh, dark in preserved specimens) stripe along sides of body and tail; orbit diameter large, 29–40% HL; suborbital width 10–14% HL........................................................................................ Hymenocephalus nascens Nascent membranehead