Paul,
There are two species in the genus, M. pomum and M. ringens and perhaps
one subspecies, M. pomum noronhensis. The type is Malea latilabris G.B.
Sowerby II, 1842, now a synonym of ringens Swainson, 1822. It is a
Panamic species.
Out of curiosity, why do you say Ranellid genus? Has Tonnidae been
lumped together with Ranellidae?
Best regards,
Travis