Edmarka
| Edmarka Temporal range: Upper Jurassic, 148Ma | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Theropoda |
| Family: | †Megalosauridae |
| Subfamily: | †Megalosaurinae |
| Genus: | †Edmarka Bakker et al., 1992 |
| Species: | † E. rex |
| Binomial name | |
| Edmarka rex Bakker et al., 1992 | |
Edmarka is a genus of dinosaur from the Late Jurassic of North America. The name honors scientist Bill Edmark. It was a theropod closely related to Torvosaurus, and may, in fact, be a junior synonym of that genus. Its fossils, including a partial skeleton, were found at Como Bluff, Wyoming.
The type species, E. rex, was described in 1992 by Robert Bakker, Donald Kralis, James Siegwarth and James Filla. They distinguished their new species from Torvosaurus tanneri by features of the jugal bone, which shows both primitive and derived features. The scapula-coracoid, ribs, and pubis were also described. Bakker et al. were impressed with the size of Edmarka, noting that it "would rival T. rex in total length," and viewing this approximate size as "a natural ceiling for dinosaurian meat-eaters." Torvosaurine megalosaurs appear to occupy the top predator niche only in the lower and middle Morrison Formation, and were replaced in the upper Morrison Formation by giant allosaurids. The presence of Torvosaurus and Edmarka in various Morrison Formation rocks upholds Dr. Robert T. Bakker's theory that there is only one large predator in a setting, and the presence of it prevents the evolution of any other.
References
- Bakker, R.T., D. Kralis, J. Siegwarth & J. Filla, 1992. Edmarka rex, a new, gigantic theropod dinosaur from the middle Morrison Formation, Late Jurassic of the Como Bluff Outcrop Region. Hunteria 2 (9): 1-24.