Birgeriidae

Fossil of Birgeria sp. in the Museo di Storia Naturale in Bergamo.

• North America, Europe, Greenland, Svalbard.

The Birgeriidae form a family of extinct bony fish of the subclass of Knorpelganoiden ( Chondrostei ) that lived from the Early Triassic to Early Jurassic.

Features

There were relatively large fish, with elongate, slender body and a long, narrow head. Dorsal and anal fin was triangular and were symmetrically, close to the deeply forked tail fin, opposite. The pectoral fins were broad and pointed, the ventral fins small. The fish were not at all or only slightly scaly. The snout was blunt with a deep mouth column far beyond the small eyes. The parasphenoid ( an unpaired covering bones in the skull base ) was elongated and rear, the back fuselage, extended also by an extension. - According T. Burgin (1990 ) Birgeria was apparently viviparous.

Outer systematics

The Birgeriidae belong to a subclass of the Knorpelganoiden ( Chondrostei ). While they were formerly attributed to the paraphyletic Palaeonisciformes, they are now considered relatives of the sturgeons and are probably the sister group of all sturgeon species ( Acipenseriformes ).

Genera

• Birgeria
• Ohmdenia
• Psilichthys