Melanonyx

(syn. Anser Ϯ Taiga Bean Goose A. fabalis) Gr. μελας melas,  μελανος  melanos  black; ονυξ onux, ονυχος onukhos  nail. "Basal half of upper mandible or parts of it, culmen and nails of both mandibles, always black  ...  Genus Melanonyx, Buturlin (1901)  ...  As to the black nails of both mandibles and the black base of the bill, in connection with the coloured band on the bill and the absence of black patches on the under-parts, these characters are quite constant, and sharply distingush the group Melanonyx from all other grey geese." (Alphéraky 1905).

Search for more names on the Key to Scientific Names in Ornithology by James A. Jobling.
Recommended citation
Jobling, J. A. (2018). Key to Scientific Names in Ornithology. In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2018). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from www.hbw.com on 11 December 2018).