Procoptodon

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Procoptodon
Temporal range: Pleistocene
Procoptodon goliah.jpg
Procoptodon goliah
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupiala
Order: Diprotodontia
Family: Macropodidae
Subfamily: Sthenurinae
Genus: Procoptodon
Owen, 1873
Species
  • P. browneorum (Merrilees, 1968)
  • P. cegsai (Pledge, 1992)
  • P. gilli (Merrilees, 1968)
  • P. goliah (Owen, 1845) (type species)
  • P. maddocki (Flannery & Hope, 1984)
  • P. mccoyi (Turnbull, Lundelius & Tedford, 1992)
  • P. oreas (De Vis, 1895)
  • P. otuel Owen, 1874
  • P. pusio Owen, 1874
  • P. rapha Owen, 1874
  • P. texasensis Archer, 1978
  • P. williamsi Prideaux, 2004

Procoptodon[1] was a genus of giant short-faced kangaroo living in Australia during the Pleistocene epoch. P. goliah, the largest known kangaroo that ever existed, stood approximately 2 m (6.6 ft).[2] They weighed about 230 kg (510 lb).[3] Other members of the genus are smaller however and Procoptodon gilli is the smallest of all of the sthenurine kangaroos, standing ~1m tall.

Giant short-faced kangaroos had a flat face and forward-pointing eyes. On each foot they had a single large toe somewhat similar in appearance like a horse's hoof. On these unusual feet they moved quickly through the open forests and plains, where they sought grass and leaves to eat. Their front paws were equally strange: each front paw had two extra-long fingers with large claws. It is possible that they were used to grab branches, bringing leaves within eating distance. Their robust skull architecture and shortened face has been thought to be related to increased masseter muscles used to chew foods. Dental microwear of P. goliah supports a browse diet, however stable isotopic data suggested its diet consisted of plants utilising a C4 photosynthetic pathway, typically associated with grasses. In this case however chenopod saltbushes found throughout semi-arid Australia was considered a more likely source of the C4 signature.[4]

The genus was present until at least about 50,000 years ago before going extinct, although there is some evidence they may have survived to as recently as 18,000 years ago. Its extinction may have been due to climate shifts during the Pleistocene.[2]

Fossils of giant short-faced kangaroos have been found at the Naracoorte World Heritage fossil deposits in South Australia, Lake Menindee in New South Wales, Darling Downs in Queensland, and at many other sites. A full-size, lifelike replica is on permanent display with other ancient native Australian animals at the Australian Museum.[2]

The genus is paraphyletic, derived from Simosthenurus.[5]

References[edit]

  1. ^ Haaramo, M. (2004-12-20). "Mikko's Phylogeny Archive: Macropodidae - kenguroos". Retrieved 2007-03-15. 
  2. ^ a b c "Procoptodon goliah". Australian Museum. Retrieved 2012-03-22. 
  3. ^ Helgen, K.M., Wells, R.T., Kear, B.P., Gerdtz, W.R., and Flannery, T.F. (2006). "Ecological and evolutionary significance of sizes of giant extinct kangaroos". Australian Journal of Zoology 54 (4): 293–303. doi:10.1071/ZO05077. 
  4. ^ Prideaux, Gavin J., et al. "Extinction implications of a chenopod browse diet for a giant Pleistocene kangaroo." Proceedings of the National Academy of Sciences 106.28 (2009): 11646-11650.
  5. ^ Prideaux G (2004). "Systematics and Evolution of the Sthenurine Kangaroos". University of California Publications in Geological Sciences 146: 1–642. Retrieved 2012-03-22.