Procoptodon

Procoptodon physiology was likely similar to that of the contemporary kangaroos; however, Procoptodon goliah was characterised by its large size. These sthenurines, or short-faced kangaroos, included species that were more than three times the size of the largest kangaroos living today. The largest, P. goliah, was tall and weighed up to . These animals lived alongside modern species of kangaroos, but specialised on a diet of leaves from trees and shrubs. Procoptodon were large and short-faced, distinguishable by their flat faces and forward-pointing eyes. On each foot, they had a single large toe or claw, similar in appearance to a horse's hoof. On feet, Procoptodon would have moved quickly through the open forests and plains, where they sought grass and leaves to eat. Both two of their front paws had two extra long fingers with large claws. These long claws may have been used to grab branches, and bring leaves to a distance where the animal could eat them. == Distribution and habitat ==

Procoptodon is mainly known for living in semiarid areas of South Australia and New South Wales. These environments were harsh, characterised by vast areas of treeless, wind-blown sand dunes. However, the area around Lake Menindee, in western New South Wales, had a cooler, wetter climate at the time Procoptodon existed. The surrounding area was a mosaic of sclerophyll forest, woodland, savannah, and plains, but sand dunes would have also formed along the edges of the Menindee. == Palaeobiology ==

Mobility Procoptodon was not able to hop as a mode of transportation, and would have been unable to accelerate sufficiently due to its weight. A more likely suggestion, based on the apparent anatomy allowed by the bone structure of P. goliah, is that unlike modern kangaroos, which are plantigrade hoppers at high speeds and use their tails in pentapedal locomotion at slower speeds, Procoptodon was an unguligrade biped, walking in a fashion similar to hominids. Locomotion mechanics and physiology have been investigated through the examination of musculoskeletal scaling patterns. The largest, P. goliah, was tall and weighed up to . Ruptures in tendons demonstrate strain in elasticity of muscles in the limbs, which provides evidence that perhaps the hypothesised ability for P. goliah to hop may have been unlikely. 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, the Darling Downs in Queensland, and at many other sites. A full-sized, lifelike replica is on permanent display with other ancient native Australian animals at the Australian Museum. Enamel bioapatite δ44/42Ca measurements indicate that dicots featured very heavily in the diet of Procoptodon. Dental microwear of P. goliah supports a browsing diet. Large bicuspids, crenulated dental crowns, and a massive bony jaw present in the fossil evidence of P. goliah would have been required to process and digest a substantial amount of leafy fodder. Through the study of isotopic composition of P. goliah tooth enamel, in addition to biomechanical bone features, dietary clues and feeding behavior have been deduced. The osteological characters furnish evidence of P. goliahs ability to handle fibrous vegetables and salt consumption. This, in turn, leads to the belief that the species needed to be close to a water source to deal with salt intake; at the same time, though, some theories are beginning to arise that limb remains indicate the ability to travel distances both to and from water sources. == Extinction ==

The genus was present until at least about 45,000 years ago before going extinct, although some evidence indicates it may have survived to as recently as 18,000 years ago. Its extinction may have been due to climate shifts during the Pleistocene, More evidence that this extinction was facilitated by human interaction is that the time period in which the extinction occurred was characterised by a relatively stable climate. --> Some evidence supports both of the claims that the extinction of P. goliah may have been due to climate shifts during the Pleistocene or to human hunting. P. goliah, depending heavily on free-standing water, was more vulnerable to drought. This can explain why the red kangaroo survived the increasing aridity and P. goliah did not. However, there is also evidence that suggests that humans could have a significant influence in the extinction of P. goliah. P. goliahs need for a constant free-standing source of water, plus its height and common habitat in open shrublands, made it more noticeable to human hunters, thus making it vulnerable to humans, who were also water-bound like it was. ==References==