Mammalodon
| Mammalodon Temporal range: Late Oligocene | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Cetacea |
| Suborder: | Mysticeti |
| Family: | †Mammalodontidae |
| Genus: | †Mammalodon |
| Binomial name | |
| †Mammalodon colliveri (type) Pritchard 1939 | |
Mammalodon is an extinct genus of archaic baleen whales,[1] although it lacked baleen and retained teeth.[2] It was discovered in 1932 in the Jan Juc Formation on the small Bird Rock island south of the Point Lillias peninsula in Torquay, Victoria in Australia (38°18′S 144°18′E / 38.3°S 144.3°E, paleocoordinates 52°54′S 142°12′E / 52.9°S 142.2°E).[3] It is one of two genera in the family Mammalodontidae.
Description
Mammalodon, with a length of 3 m (9.8 ft), was smaller and more basal than modern baleen whales.[4]
Mammalodon is a mix of archaeocete plesiomorphies (retained primitive traits) and mysticete synapomorphies (traits shared with more derived taxa), such as a short rostrum, reduced premaxillae, and orbits directed anterodorsally — defining features of mysticete.[5]
It had a short face and a delicate premaxilla with only one or two incisors, and the lateral rim of the internal auditory meatus was lengthened towards the brain case which formed a longitudinal ridge.
Palaeobiology
As with the closely related genus Janjucetus, Mammalodon lacked baleen, instead possessing well-developed teeth.[2] As such, it was not able to filter-feed in the same manner as extant baleen whales, making its diet and ecological niche a mystery.[2] As the teeth are widely spaced, they may have developed a method of filter-feeding unlike that of other whales. It may have been a bottom filter feeder, its blunt snout helping to suck up organisms from the sea floor.[6]
References
- ↑ Fitzgerald 2006, p. 2959
- 1 2 3 Fitzgerald 2006, p. 2961
- ↑ Bird Rock, Torquay, Victoria - Jan Juc Fm (Oligocene of Australia) in the Paleobiology Database. Retrieved October 2013.
- ↑ Discover December 2009
- ↑ Fitzgerald 2010, Abstract
- ↑ Fitzgerald 2010
Further reading
- Fitzgerald, Erich M. G. (2006). "A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales". Proceedings of the Royal Society B 273: 2955–2963. doi:10.1098/rspb.2006.3664. PMC 1639514. PMID 17015308.
- Fitzgerald, Erich M. G. (2010). "The morphology and systematics of Mammalodon colliveri (Cetacea: Mysticeti), a toothed mysticete from the Oligocene of Australia". Zoological Journal of the Linnean Society 158 (2): 367–476. doi:10.1111/j.1096-3642.2009.00572.x.
- Israel, Brett (December 2009). "Early Mini-Whale Slurped up Mud to Find Hidden Prey". Discover Magazine. Retrieved October 2013.
- Pritchard, B. G. (1939). "On the discovery of a fossil whale in the older Tertiaries of Torquay, Victoria". The Victorian Naturalist 55 (9): 151–159. Retrieved October 2013. Lay summary (October 2013).