Sternoptyx
Sternoptyx is an oceanic ray-finned fish genus which belongs in the family Sternoptychidae. This is the type genus of the Sternoptychidae, as well as the marine hatchetfish subfamily Sternoptychinae.
Sternoptyx have silvery, high, and laterally compressed bodies and large, non-telescopic eyes. They are all relatively small, with even the largest species not exceeding standard length.
Species
There are currently four recognized species in this genus:Sternoptyx diaphana Hermann, 1781 Sternoptyx obscura Garman, 1899Sternoptyx pseudobscura R. C. Baird, 1971 Sternoptyx pseudodiaphana Borodulina, 1977Fossils of this genus show that they have existed at least since the Early Oligocene, about 30 million years ago.