The type species, Australosomus merlei from Madagascar, was first described as Pristisomus merlei by Ferdinand Priem. A new genus, Australosomus, was later erected for this species by Jean Piveteau.
Most species were marine, except for the African species, which were found in freshwaterdeposits.
The genus name Australosomus ("southern body") is inaccurate, as Australosomus is known as far north as Canada and Greenland, although the first known remains were described from Madagascar.
Indeterminate remains are known from the Sulphur Mountain Formation of British Columbia and Alberta (Canada). The remains of a potentially associated genus are known from the Late Triassic Chinle Formation of Arizona. Potential remains are known from the Permian-Triassic boundary of Kenya.
Appearance
Australosomus was an elongate fish. The interlocking scales (3 to 4 times long as wide), deeply forked caudal fin all help to distinguish this genus. It achieved standard lengths of about 100mm (3.9in) to 310mm (12in).
↑Piveteau, Jean (1930). "Particularités structurales d'un type nouveau de poisson fossile des formations permo-triasiques du nord de Madagascar". Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences (in French). 191: 456–458.