Australosomus ("southern body") is an extinct genus of prehistoric bony fish from the Lower Triassic.
Fossils have been found in Greenland, Kenya, Tanzania, Madagascar, South Africa and Canada (British Columbia). Most Australosomus species were marine, except the ones from Africa.
It is said that Australosomus was a small predator that ambushed other fish. As mentioned before, it lived in both marine and freshwater habitats.
A small to medium-sized fish, Australosomus had a forked caudal fin. The body was tapered and long. It had a dorsal fin and an anal fin, which was placed in a backward position.
Australosomus is from the Pholidopleuriformes, a small order of ray-finned fish typical of the Triassic.
Australosomus was first described by Jean Piveteau in 1930. The type species, Australosomus merlei, was called Pristisomus merlei at the time by Ferdinand Priem.