Cercamia melanogaster is your newest described cardinalfish
Cercamia melanogaster is described from West Papua, Indonesia from a "dark crevice on a near-vertical wall at a depth of about 15m." Like most cardinalfish, C.melanogaster appears to be nocturnal, emerging from the crevices at dusk. This is a tiny species whose total length is barely above one inch (3cm). Melanogaster means "black stomach" - a perfect nomenclature for this new cardinalfish.
If not for its nocturnal behavior, C.melanogaster would make for a very nice nano fish. It is also likely very easy to breed in captivity like most Apogonids.
Gerald R Allen, Mark V Erdmann, and Angka Mahardini describes Cercamia melanogaster in the latest issue of Journal of the Ocean Science Foundation.