All the members of the two
extant genera,
Aspidodiadema and
Plesiodiadema, are found in tropical seas at
bathyal and
abyssal depths, often on the submarine slopes of islands. The genera
Culozoma,
Eosalenia, and
Gymnotiara are known only from the
fossil record. Study of the larval development of
Aspidodiadema jacobyi suggests that the family should be elevated to ordinal status as a sister
clade of the order
Diadematoida, or possibly be regarded as a sister clade of the other families within that order. ==Genera==