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 Temporal range: Early Oligocene to Present 40–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Diaphanous hatchetfish (S. diaphana)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Stomiiformes
Family:	Sternoptychidae
Subfamily:	Sternoptychinae
Genus:	Sternoptyx Hermann, 1781

Sternoptyx have silvery, high, and laterally compressed bodies and large, non-telescopic eyes.^[1] They are all relatively small, with even the largest species (S. pseudobscura and S. pseudodiaphana) not exceeding 60 millimetres (2.4 in) standard length.^[2]

Species

There are currently four recognized species in this genus:^[2]

• Sternoptyx diaphana Hermann, 1781 (Diaphanous hatchetfish)
• Sternoptyx obscura Garman, 1899
• Sternoptyx pseudobscura R. C. Baird, 1971 (Highlight hatchetfish)
• Sternoptyx pseudodiaphana Borodulina, 1977 (False oblique hatchetfish)

Fossils of this genus show that they have existed at least since the Early Oligocene, about 30 million years ago.^[3]