![]() | It has been suggested that Simosthenurus occidentalis be merged into this article. (Discuss) Proposed since April 2024. |
Simosthenurus Temporal range: Pleistocene | |
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S. occidentalis skeleton at American Museum of Natural History | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Infraclass: | Marsupialia |
Order: | Diprotodontia |
Family: | Macropodidae |
Genus: | † Simosthenurus Tedford, 1966 |
Species | |
S. maddocki Contents |
Simosthenurus, also referred to as the short-faced kangaroo, is an extinct genus of megafaunal macropods that existed in Australia, specifically Tasmania, during the Pleistocene. Analysis of Simosthenurus fossils has contributed to the finding that there are three lineages of macropods: Sthenurinae, Macropodinae, and Lagostrophinae. [1] The genus Simosthenurus was among the sthenurines.
The two most documented members of the genus are S. maddocki and S. occidentalis, though other species have also been discovered.
Osteological information (predominantly cave floor surface finds [1] ) has yielded that Simosthenurus is part of the same family as that of modern kangaroos. [2] However, modern kangaroos are plantigrade hoppers, using jumping as their means of locomotion, while Simosthenurus was a bipedal unguligrade, walking in a manner similar to that of hominids. [3] Although members of Simosthenurus were no taller than most modern species of kangaroo, their robust bones, broad pelvis, long arms and short necks were unique adaptations to their browsing mode of feeding. They had single-toed hind feet had small hoof-like nails more typical of animals adapted to moving over relatively flat terrain. [4] Simosthenurus is a highly distinct lineage of macropods, with no living descendants. However, it is possible that their closest living cousin is the banded hare-wallaby, which is now restricted to small isolated islands off the coast of Western Australia. [5]
S. occidentalis mtDNA sequences were obtained from fossils in Tasmanian caves; the fossils yielded radiocarbon dates between 46,000 and 50,000 years ago. The sequences obtained in this study were from fossils much older than any Australian fossils that previously yielded sequences. [1]
S. occidentalis was a leaf-eating marsupial, about the size of a modern grey kangaroo, though far more robust, with adults estimated to be about 118 kg. The species has been suggested to have used a bipedal striding gait when moving slowly. This is unlike modern kangaroos, which use pentapedal motion, or 'punting', pushing off their tail and forelimbs and swinging their hindlimbs forward when moving slowly. [1] It is thought that, by rearing up on their hind limbs and using their long arms and fingers, they could reach overhead to grasp high leaves and branches and pull them down to their mouth. They then would use their powerful jaws and striated teeth to grind the tough leaves. [4]
An adult S. maddocki was smaller than S. occidentalis, weighing only 78 kg. [1] Like some other species from the same time period, they were apparently highly selective feeders. Local records indicate that the species was mainly located in southeastern Australia. It is uncommon to find fossils of this rare species, especially when compared to other Sthenurines.
There are several proposed causes of the extinction of Simosthenurus. The two most popular hypotheses include human involvement and climate change.
One theory postulates that human impact caused it. There are fewer extinct megafaunal Tasmanian species compared to those of continental Australia. This is most likely due to humans arriving in mainland Australia first. The extinction of Simosthenurus may be attributable to human over-hunting or habitat alteration. [6] However, there is no archaeological evidence for interactions with humans, and the overlap of habitation in Australia and Tasmania of both humans and Simothenurus species, if there was one, would have been relatively short. [7]
Another theory is that climate change caused the extinction of this genus. The last glacial period, popularly known as the Ice Age, has been linked with a severe reduction in several megafaunal populations, including Simosthenurus. [8]
Diprotodon is an extinct genus of marsupial from the Pleistocene of Australia containing one species, D. optatum. The earliest finds date to 1.77 million to 780,000 years ago but most specimens are dated to after 110,000 years ago. Its remains were first unearthed in 1830 in Wellington Caves, New South Wales, and contemporaneous paleontologists guessed they belonged to rhinos, elephants, hippos or dugongs. Diprotodon was formally described by English naturalist Richard Owen in 1838, and was the first named Australian fossil mammal, and led Owen to become the foremost authority of his time on other marsupials and Australian megafauna, which were enigmatic to European science.
The thylacine, also commonly known as the Tasmanian tiger or Tasmanian wolf, is an extinct carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea. The thylacine died out in New Guinea and mainland Australia around 3,600–3,200 years ago, prior to the arrival of Europeans, possibly because of the introduction of the dingo, whose earliest record dates to around the same time, but which never reached Tasmania. Prior to European settlement, around 5,000 remained in the wild on Tasmania. Beginning in the nineteenth century, they were perceived as a threat to the livestock of farmers and bounty hunting was introduced. The last known of its species died in 1936 at Hobart Zoo in Tasmania. The thylacine is widespread in popular culture and is a cultural icon in Australia.
In zoology, megafauna are large animals. The precise definition of the term varies widely, though a common threshold is approximately 45 kilograms (99 lb), with other thresholds as low as 10 kilograms (22 lb) or as high as 1,000 kilograms (2,200 lb). Large body size is generally associated with other traits, such as having a slow rate of reproduction, and in large herbivores, reduced or negligible adult mortality from being killed by predators.
Macropodidae is a family of marsupials that includes kangaroos, wallabies, tree-kangaroos, wallaroos, pademelons, quokkas, and several other groups. These genera are allied to the suborder Macropodiformes, containing other macropods, and are native to the Australian continent, New Guinea and nearby islands.
The tammar wallaby, also known as the dama wallaby or darma wallaby, is a small macropod native to South and Western Australia. Though its geographical range has been severely reduced since European colonisation, the tammar wallaby remains common within its reduced range and is listed as "Least Concern" by the International Union for Conservation of Nature (IUCN). It has been introduced to New Zealand and reintroduced to some areas of Australia where it had been previously extirpated. Skull variations differentiate between tammar wallabies from Western Australia, Kangaroo Island, and mainland South Australia, making them distinct population groups.
Potoroidae is a family of marsupials, small Australian animals known as bettongs, potoroos, and rat-kangaroos. All are rabbit-sized, brown, jumping marsupials and resemble a large rodent or a very small wallaby.
Pademelons are small marsupials in the genus Thylogale, found in Australia and New Guinea. They are some of the smallest members of the macropod family, which includes the similar-looking but larger kangaroos and wallabies. Pademelons are distinguished by their small size and their short, thick, and sparsely-haired tails. Like most other marsupials, they carry their young in a pouch.
The banded hare-wallaby, mernine, or munning is a marsupial currently found on the islands of Bernier and Dorre off western Australia. Reintroduced populations have recently been established on islands and fenced mainland sites, including Faure Island and Wadderin Sanctuary near Narembeen in the central wheatbelt.
The term Australian megafauna refers to the megafauna in Australia during the Pleistocene Epoch. Most of these species became extinct during the latter half of the Pleistocene, and the roles of human and climatic factors in their extinction are contested.
Procoptodon 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 2 m (6.6 ft). They weighed about 200–240 kg (440–530 lb). Other members of the genus were smaller, however; Procoptodon gilli was the smallest of all of the sthenurine kangaroos, standing approximately 1 m tall.
Sthenurinae is a subfamily within the marsupial family Macropodidae, known as short-faced kangaroos or sthenurine kangaroos. No members of this subfamily are extant today, with all becoming extinct by the late Pleistocene. Procoptodon goliah, the largest macropodid known to have existed, was a sthenurine kangaroo, but sthenurines occurred in a range of sizes, with Procoptodon gilli being the smallest at the size of a small wallaby.
The mammals of Australia have a rich fossil history, as well as a variety of extant mammalian species, dominated by the marsupials, but also including monotremes and placentals. The marsupials evolved to fill specific ecological niches, and in many cases they are physically similar to the placental mammals in Eurasia and North America that occupy similar niches, a phenomenon known as convergent evolution. For example, the top mammalian predators in Australia, the Tasmanian tiger and the marsupial lion, bore a striking resemblance to large canids such as the gray wolf and large cats respectively; gliding possums and flying squirrels have similar adaptations enabling their arboreal lifestyle; and the numbat and anteaters are both digging insectivores. Most of Australia's mammals are herbivores or omnivores.
Macropus is a marsupial genus in the family Macropodidae. It has two extant species of large terrestrial kangaroos. The term is derived from the Ancient Greek μάκρος, makros "long" and πους, pous "foot". Thirteen known extinct species are recognised. The type species is the eastern grey kangaroo.
Sthenurus 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, halfway through the Miocene, and then its population grew during the Pliocene.
Protemnodon is an extinct genus of megafaunal macropodids that existed in Australia, Tasmania, and New Guinea in the Pliocene and Pleistocene. Members of this genus are also called giant kangaroos.
The Late Pleistocene to the beginning of the Holocene saw the extinction of the majority of the world's megafaunal animal species, which resulted in a collapse in faunal density and diversity across the globe. The extinctions during the Late Pleistocene are differentiated from previous extinctions by its extreme size bias towards large animals, and widespread absence of ecological succession to replace these extinct megafaunal species, and the regime shift of previously established faunal relationships and habitats as a consequence. The timing and severity of the extinctions varied by region and are thought to have been driven by varying combinations of human and climatic factors. Human impact on megafauna populations is thought to have been driven by hunting ("overkill"), as well as possibly environmental alteration. The relative importance of human vs climatic factors in the extinctions has been the subject of long-running controversy.
The Macropodidae are an extant family of marsupial with the distinction of the ability to move bipedally on the hind legs, sometimes by jumping, as well as quadrupedally. They are herbivores, but some fossil genera like Ekaltadeta are hypothesised to have been carnivores. The taxonomic affiliations within the family and with other groups of marsupials is still in flux. Macropodids are considered to be the most diverse group of marsupial herbivores ever to have evolved, and have been the subject of more phylogenetic studies than any other marsupial family.
Simosthenurus occidentalis is a species of sthenurine marsupial that existed in Australia during the Pliocene, becoming extinct in the Pleistocene epoch around 42,000 years ago. It was a large herbivorous biped that resembles large kangaroos, but with a heavier body than modern kangaroos. The structure of the skull and teeth - resembling koalas and panda bears - indicates that it consumed tough vegetation.
Cookeroo is a genus of extinct kangaroos from the Late Oligocene and Early Miocene found in fossil deposits from the Riversleigh World Heritage Area, in Australia. The genus includes two species, C. bulwidarri and C. hortusensis.
Bohra is an extinct genus of macropod from the Plio-Pleistocene of Australia. It is closely related to modern tree kangaroos (Dendrolagus), and like them is thought to have had an arboreal lifestyle, with some species of Bohra substantially exceeding living tree kangaroos in size.