Прокоптодон: гигантский вымерший кенгуру плеистоцена

Extinct genus of marsupials
Automatic taxobox
| fossil range =
| image = Simosthenurus gilli skull. jpg
| image caption = Procoptodon gilli skull. | taxon = Procoptodon
| authority = Owen, 1873
| type species = P. goliah
| subdivision ranks = Species is an extinct genus of giant short faced (sthenurine) kangaroos that lived in Australia during the Pleistocene Epoch. P. goliah, the largest known kangaroo species that ever existed, stood at about They weighed about Other members of the genus were smaller, however; Procoptodon gilli was the smallest of all of the sthenurine kangaroos, standing approximately tall. The genus is derived from Simosthenurus, making the latter genus paraphyletic. 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.

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.

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. Similar to Macropus giganteus, Procoptodon has molar patterns that indicate they had a similar, grassy, herbivorous diet (as opposed to leaves) and were grazers, but determining specific diets and preference of extinct herbivores is admittedly difficult. 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. 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.