Birgeriidae
| Birgeriidae | ||||||||||||
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Fossil of Birgeria sp. in the Museo di Storia Naturale in Bergamo . |
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| Temporal occurrence | ||||||||||||
| Lower Triassic to Lower Jurassic | ||||||||||||
| 249.7 to 199.6 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Birgeriidae | ||||||||||||
| Berg , 1940 |
The Birgeriidae form a family of extinct bony fish from the subclass of the cartilaginous organoids (Chondrostei), which lived from the Lower Triassic to the Lower Jurassic .
features
They were relatively large fish, with an elongated, slender body and a long, narrow head. The dorsal and anal fins were triangular and stood symmetrically opposite each other, close to the deeply forked caudal fin. The pectoral fins were broad and pointed, the pelvic fins small. The fish were scales only slightly or not at all. The muzzle was blunt with a deep crevice that stretched far behind the small eyes. The parasphenoid (an unpaired cover bone in the base of the skull) was elongated and at the back, towards the trunk, was additionally lengthened by an extension. According to T. Bürgin (1990) Birgeria was apparently viviparous.
External system
The Birgeriidae belong to the subclass of the cartilaginous organoids (Chondrostei). While they used to be assigned to the paraphyletic Palaeonisciformes , today they are considered relatives of the sturgeon and are probably the sister group of all sturgeon-like (Acipenseriformes).
Genera
literature
- Karl Albert Frickhinger: Fossil Atlas of Fishes. Mergus, Verlag für Natur- und Heimtierkunde Baensch, Melle 1999, ISBN 3-88244-018-X .
- Joseph S. Nelson : Fishes of the World. 4th edition. John Wiley & Sons, Hoboken NJ 2006, ISBN 0-471-25031-7 .
Web links
- Palæos: Birgeriidae