Sthenurus

Extinct genus of marsupials

Sthenurus ("strong tail") is an extinct genus of kangaroos. With a length around 3 m (10 ft), some species were twice as large as modern extant species. Sthenurus was related to the better known Procoptodon. The subfamily Sthenurinae is believed to have separated from its sister taxon, the Macropodinae (kangaroos and wallabies), halfway through the Miocene, and then its population grew during the Pliocene.

A 1997 study analysed the diets of the fauna at various fossil site localities in South Australia, using stable carbon isotope analysis 13C/12C of collagen. It found that at older localities such as Cooper Creek, the species of Sthenurus were adapted to a diet of leaves and twigs (browsing) due to the wet climate of the time between 132 and 108 thousand years ago (kya by thermoluminescence dating and uranium dating), which allowed for a more varied vegetation cover. At the Baldina Creek fossil site 30 kya (C14 dating), the genus had transitioned to a diet of grass grazing. During this time, the area was open grasslands with sparse tree cover as the continent was drier than today, but at Dempsey's Lake (36 25 kya) and Rockey River (19 kya C14 dating), their diet was of both grazing and browsing. This analysis may be because of a wetter climatic period. The overall anatomy of the genus did not alter in response to the change in diet and dentition did not adapt to the varying toughness of the vegetation between grasses, shrubs, and trees. Other animals found in the Cuddie Springs habitat include the flightless bird Genyornis, the red kangaroo, Diprotodon, humans, and many others. Examination of skeletal remains of Sthenurus from Lake Callabonna, northern South Australia, revealed that as the animals were trapped as they floundered in the clay mud while attempting to cross the floor of the lake during low water or dry times. The data show that three closely allied sthenurine species coexisted sympatrically at Lake Callabonna: a new giant taxon, S. stirlingi, an intermediate sized S. tindalei, and the considerably smaller S. andersoni. Comparative osteology of these Sthenurus species with Macropus giganteus emphasizes how different sthenurine kangaroos were from extant kangaroos, especially with the sthenurines' short, deep skulls, long front feet with very reduced lateral digits, and the monodactyl hind feet. Teapot Creek, a tributary of the MacLaughlin River in the Southern Monaro, southeastern New South Wales, contains a sequence of terraces. The highest and oldest of these terraces was reported to contain the remains of fossil mammals found in Plio Pleistocene fossil deposits elsewhere in eastern Australia. Sthenurus atlas, S. occidentalis, and S. newtonae are some of the species identified from the fossils found in the terrace.

Examining the structure and lifestyle of this species is difficult because not much material has surfaced in regards to them. However, even within the rarity of discoveries relating to the kangaroo like species, scientists were able to use their findings to learn more about their lifestyles. For example, scientists broke down the few bones that they had discovered during the process of isotope analysis (which is the study of the distribution of certain isotopes that ease the process of drawing conclusions when determining food chains) and retrieved material which allowed them to draw the conclusion regarding their paleodiet. These animals were herbivores because the material they retrieved drew back to the plantation that was Australia (where their bones were found).

These structures were tough and strongly enamelled, useful for tough vegetation and with a striation pattern.

From evidence gathered at Cuddie Springs, Native Australians inhabited the same habitat as that of Sthenurus and various other extant and extinct species of animals. At this locality, a lack of any specific tools suitable for hunting seems to occur. Instead, tools used to cut meat off the bone and blood residue left on the stone tools were found. Any material made of wood for hunting, such as the boomerang and spear, has either not survived intact or was not used by the people of the time in this locality.