Giant koala
| Giant koala Temporal range: Pleistocene | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Infraclass: | Marsupialia |
| Order: | Diprotodontia |
| Family: | Phascolarctidae |
| Genus: | Phascolarctos |
| Species: | P. stirtoni |
| Binomial name | |
| Phascolarctos stirtoni Bartholomai, 1968 | |
The giant koala (Phascolarctos stirtoni) is an extinct arboreal marsupial which existed in Australia during the Pleistocene epoch. Phascolarctos stirtoni was about one third larger than the contemporary koala, P. cinereus,[1] and has had an estimated weight of 29 lb (13 kg), which is the same weight as a large contemporary male koala.[2] Although considered a part of the Australian megafauna, its body mass excludes it from most formal definitions of megafauna. It is better described as a more robust koala, rather than a "giant"; in contrast, a number of Australian megafauna, such as Diprotodon and Procoptodon goliah, were unambiguously giants.The two koala species co-existed during the Pleistocene, occupying the same arboreal niche.[1] The reason for the extinction of the larger of the two about 50,000 years ago is unknown, although there are various hypotheses for the extinction.
Description
The giant koala is an arboreal marsupial weighing about twice as much as a koala, about 30 kg. It is known as the largest tree dwelling marsupial that has ever lived. Scientists say that there is a clear similarity in the physical appearance from the modern koala.[3] It is assumed that the diet of the giant koala is eucalyptus leaves, and that the giant koala was in fact a folivore.
Extinction
Fossil remains of P. stirtoni have been discovered in Lake Eyre and Tarkarooloo basins in South Australia.[4] It was once thought that the modern-day koala was descended from the giant koala, but this is now determined to be incorrect. Gilbert Price, of the University of Queensland, used improved dating techniques to analyze fossils of both types of koala to find that the two species were living together in the same arboreal niche.[5] Which raises the question from what did the koala descend from and why one species of koala survived and the giant koala became extinct. It is hypothesized that there was a change in climate and a restriction of food supply. Another possible reason is the hunting by humans for larger animals. The "dwarfing" hypothesis, based on the similarities of the two koalas has been used to support both ideas.[5]
References
- 1 2 "Parks South Australia: Naracoorte Caves website". Archived from the original on 2007-09-26. Retrieved 2007-10-27.
- ↑ Prideaux, Gavin J.; Roberts, Richard G.; Megirian, Dirk; Westaway, Kira E.; Hellstrom, John C.; Olley, Jon M. (2007). "Mammalian responses to Pleistocene climate change in southeastern Australia" (PDF). Geology. 35: 33. doi:10.1130/G23070A.1.
- ↑ Design, Joy Williams—Artist Web. "JoyZine - Australian Megafauna: Giant Koala (Phascolarctos stirtoni)". www.artistwd.com.
- ↑ http://www.artistwd.com/joyaustralia/articles/megafauna/phascolarctos_stirtoni.php#.VmWMU7grKUk
- 1 2 "Scientists unlock secrets of Australia's giant 30kg koalas". 4 January 2009.
- Piper, Katarzyna J. (2005). "An Early Pleistocene Record of a Giant Koala (Phascolarctidae, Marsupalia) from Western Victoria" (PDF). Australian Mammalogy. CSIRO Publishing. 2 (27): 221–223. doi:10.1071/AM05221.
- "Giant Koala Phascolarctos stirtoni". JoyZine. Art Web Design. Retrieved 1 December 2015.
- Marks, Kathy (22 October 2011). "Scientists unlock secrets of Australia's giant 30kg koalas". Independent. Retrieved 2 December 2015.