Cyrtomaia Miers, 1886 (type species Cyrtomaia murrayi Miers, 1886, subsequent designation by Guinot & Richer de Forges, 1982 b; gender feminine)
Echinomaia Borradaile, 1916 (type species Echinomaia hispida Borradaile, 1916, by monotypy; gender feminine)
Remarks. The genus Cyrtomaia Miers, 1886, was established for C. murrayi Miers, 1886, from Indonesia (type species selected by Guinot & Richer de Forges 1982 b). Guinot & Richer de Forges (1982 a, b) partially reviewed the genus and recognized 21 species. Griffin & Tranter (1986), however, disagreed with the validity of some of the characters proposed by Guinot & Richer de Forges (1982 a, b), arguing that there was more extensive variation than was previously recognized, especially for taxa in which there was little material, and as a result recognized only 17 species. Guinot & Richer de Forges (1986), utilizing the extensive material collected by the MUSORSTOM 2 expedition, disagreed with some of Griffin & Tranter’s arguments, and further discussed the validity of some species. Richer de Forges & Guinot (1988, 1990) and Richer de Forges & Ng (2007 a, b) subsequently described more species. In this study, we recognise 29 species, all of which are characteristic of the upper bathyal zone, occurring between 200 and 1000 m deep.