Review of the deepwater cardinalfish genus Microichthys Rüppell 1852, with the description of a new species from the Azores Islands (Teleostei: Epigonidae)

The epinonid fish genus Microichthys Rüppell 1852 is reviewed. The genus includes three valid species: M. coccoi Rüppell 1852 and M. sanzoi Spartà 1950 from the Mediterranean Sea; M. atlanticus sp. nov. from the Azores, northeastern Atlantic Ocean, characterized by the following combination of characters: dorsal-fin rays VII + I, 8–9; anal-fin rays II, 8; total pectoral-fin rays 18; total gill rakers 20–23; pyloric caeca 4; pored lateral-line scales 41–43 + 2; vomerine teeth 6, in a single row; denticles on posterior margin of preopercle 6–21, on lower margin 1–2; nape slightly humped; bony rim of orbit not raised above dorsal profile; ridge present in interorbital region; oblique dark lateral bars 18–22, lower counter-bars 7; vertical black bar on anterior caudal peduncle absent; peritoneum pale; pelvic fins pale. A key to the species of Microichthys is presented.