| Ischyodus | |
|---|---|
) | |
| Ischyodus avitus | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Subclass: | |
| Order: | Chimaeriformes |
| Family: | Callorhynchidae |
| Genus: | †Ischyodus Egerton, 1843 |
| Species | |
| |
Ischyodus is an extinct genus of cartilaginous fish belonging to the subclass Holocephali, which includes the modern-day chimaeras. Fossils are known from Europe (including Russia), North America, and New Zealand.
Ischyodus was rather similar to the present-day chimaera Chimaera monstrosa, which is found in the Atlantic Ocean and Mediterranean Sea. Just like C. monstrosa, Ischyodus had large eyes, a long whip-like tail, small lips, large pectoral fins and dorsal fin, and a dorsal spike attached to the front of the dorsal fin. The spike probably served as a method of protection against predators, and may have been venomous, as it is in modern chimaeras.[1]
Dental plates of at least two species, Ischyodus rayhaasi and Ischyodus dolloi, have been found at several sites in North Dakota.[2]
References
- ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 29. ISBN 1-84028-152-9.
- ^ Hoganson, J. W. and J. M. Erickson. 2005. A new species of Ischyodus (Chondrichthyes: Holocephali: Callorhynchidae) from Upper Maastrichtian shallow marine facies of the Fox Hills and Hell Creek formations, Williston Basin, North Dakota, USA. Palaeontology 48: 709-721. doi:10.1111/j.1475-4983.2005.00475.x
External links