|Triassic Fossil Fish, Albertonia sp. |
Specimens of this beauty have been found in the Vega-Phroso Siltstone Member of the Sulphur Mountain Formation near Wapiti Lake in British Columbia and the Lower Triassic Montney Formation of Alberta.
Early Triassic fish have been described from several outcrops in the Western Canada Sedimentary Basin of the Rocky Mountains. The best known and most prolific of these are from sites near Wapiti Lake in northeastern British Columbia. Here specimens of bony fish with their heavy ganoid and cosmoid scales are beautifully preserved. Four genera of Early Triassic fishes — the ray-finned actinopterygians Albertonia, Bobasatrania, Boreosomus, and the lobe-finned coelacanth (sarcopterygian), Whiteia — are found in abundance in the Wapiti Lake exposures.
This particular species is one of my favourites. Albertonia is a member of the ganoid fish family Parasemionotidae, which is amongst the most advanced and abundant of Triassic subholostean families of fish. The preservation here really shows the beauty of form of this species who likely died and was preserved in sediment at the bottom of an ocean with an anoxic environment.
These fellows lived in deep marine waters, dining on plankton & other small organisms. Most specimens are 35-40cm in length. They have a large, sail-shaped dorsal fin and rather smallish ventral fins. Their pectoral fins were incredibly long compared to the rest of the body, and they too resembled sails. The preservation here is quite remarkable with each square-shaped scale preserved in minute detail.
Richard Carr, a grad student at Fort Hays State University mentioned to me that there is a great fish taphonomy paper based on these specimens. The Sulphur Mountain Formation also has some other incredible fish fossils including 3-D articulated hybodont and eugeneodont skeletons. The latter are also among the youngest members of their order.