Squalodon
| Squalodon | |
|---|---|
| File:Squalodon.gif | |
| Reconstruction of Squalodon | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Order: | |
| Suborder: | |
| Superfamily: | |
| Family: | Squalodontidae
|
| Genus: | Squalodon
|
Squalodon is an extinct genus of whales, belonging to the superfamily Squalodontoidea and family Squalodontidae. Named by Grateloup in 1840, it was originally believed to be an iguanodontid dinosaur but has since been reclassified. The name Squalodon comes from Squallus, a genus of shark. As a result its name means "Squallus tooth."
Description
Squalodontids lived from the early-middle Oligocene into the middle Miocene. The genus Squalodon belongs to the order Odontocete, the toothed whales. The superfamily Squalodontidae is named after the shark Squallus because its cheek teeth apparently resemble the teeth of a Squallus shark. Squalodontidae consists of four different groups of medium-sized shark toothed whales. They are short snouted shark toothed whales, the Prosqualodon, the medium-snouted shark toothed whales, the Phoberodon, and the long-snouted shark toothed whales, the Squalodon, belonging to the family Squalodontidae. These unique creatures can be found throughout the world in warm waters during the Oligocene and Miocene. An explanation for the extinction of this family isn't well known. Hypotheses for why this family went extinct involve other competing dolphins and climate change (Fordyce, R.E.)
Ancestral Features
This superfamily is intriguing in that it is characterized by both ancestral and derived features. The most evident ancestral feature is that of their teeth. At this time other toothed whales were evolving simple conical teeth while Squalodontidae retained their primitive dentition that their ancestors (the archaeocetis) had developed. Squalodontid teeth are widely spaced apart; their cheek teeth are triangular and serrated for grasping and cutting. Due to the efficiency of their primitive dentition squalodontids could have a diverse variety of prey. Another ancestral quality of the Squalodontidae is that they possess mobility in their necks. Squalodontid necks are more compressed than their ancestors, the Archaeoceti. Compared to living toothed whales, the squalodontids were probably much more mobile. Paleontologists also believe that the dorsal fins were larger than that of the ancestors but still reduced.
Modern features
Shark toothed whales also possess many modern features. Their crania were well compressed, their rostrums were telescoped outward, and their skulls show proof of ability of echolocation. The unique-looking squalodontids can be found throughout the world in warm waters during the Oligocene and Miocene. Squalodontidae went extinct in the middle of the Miocene, leaving no descendants. Hypotheses of why this family lead to extinction have to deal with competition of other groups of dolphins.
See also
References
 | This prehistoric mammal-related article is a stub. You can help Wikipedia by expanding it. |