Boreosomus

Boreosomus (meaning: "boreal body") is an extinct genus of Triassic ray-finned fish. It was first described from the Arctic island of Spitsbergen (Svalbard, Norway), but was later also discovered in other parts of the world. Boreosomus had a worldwide distribution during the Early Triassic. Fossils of Boreosomus were found, apart from Spitsbergen, in Greenland, Madagascar and Canada.[2]

Boreosomus Temporal range: Early Triassic PreꞒ Ꞓ O S D C P T J K Pg N ↓
Boreosomus slab and counterslab fossils at the Geological Museum in Copenhagen
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	†Palaeonisciformes[1]
Family:	†Ptycholepidae
Genus:	†Boreosomus Stensiö, 1921
Type species
Boreosomus arcticus (Woodward, 1912)
Other species
†Boreosomus gillioti †Boreosomus piveteaui †Boreosomus reuterskioldi †Boreosomus scaber
Synonyms
Diaphorognathus Brough, 1933

Boreosomus belongs to the family Ptycholepidae (= Boreosomidae/Chungkingichthyidae). Other genera of this family are Acrorhabdus (Spitsbergen), Ardoreosomus (Nevada, United States), Chungkingichthys (China), Ptycholepis (global) and Yuchoulepis (China).[3] A characteristic feature of this family is the dorsal fin, which inserts at the level of the pelvic fins in the front part of the body.