Diprotodon

Diprotodon is considered to be one of the extinct genus of gigantic quadrupedal marsupial which is a native of Australia during the Pleistocene epoch.

In the Greek language, Diprotodon means "two forward teeth".The genus is still considered to be monotypic as it contains only Diprotodon optatum which is the largest known marsupial to have ever existed on the planet Earth. It is one of the most important members of the "Australian megafauna," which roamed the continent during the Pleistocene epoch. Diprotodon lived for around 1.6 million years before dying out about 44,000 years ago. 

Total skulls, skeletons, and foot impressions have been discovered in Diprotodon species fossils around mainland Australia. The largest specimens were about 3 m (9.8 ft) long from nose to tail, 2 m (6.6 ft) tall at the shoulder, and weighed about 2,790 kg (6,150 lb). In Quinkan traditional country, Diprotodon may have been portrayed on Aboriginal rock art paintings (Queensland, Australia). Since the initial colonization of the continent 44,000 years ago, Diprotodon has become extinct; the position of human and climatic influences in its extinction is unclear and debated.

Diprotodon is considered to be a member of the extinct family Diprotodontids. The Koala and the Wombats are considered to be the closest surviving relatives of Diprotodon. The  Diprotodon in the past has also been mentioned or referred to as the "giant wombats" in few popular areas. Some Aboriginal peoples describe Diprotodon bones as those of "bunyips," suggesting that Diprotodonts influenced stories of the bunyip.

In this article, we are going to discuss the Australian diprotodon, its discovery, taxonomy, description, and also a few of the important frequently asked questions that will also be answered. 

Discovery of Diprotodon

• From the Pleistocene of Australia, the massive Diprotodon optatum was considered to be the largest marsupial that had ever lived and is known to be the last of the extinct, herbivorous diprotodontids. Diprotodon was one of the most well-known megafauna and the first fossil mammal from Australia (Owen 1838). When the first aboriginal people settled in Australia, it was widespread, coexisting with them for thousands of years before becoming extinct about 25,000 years ago.

• In the cave near Wellington, New South Wales, the first recorded Diprotodon remains were discovered by the bushman George Ranken and Major Thomas Mitchell in the 1830s. Major Thomas Mitchell then sent the remains to England for study which was done by Sir Richard Owen.

• When Ludwig Leichhardt found many Diprotodon fossils eroding from the banks of creeks in Queensland's Darling Downs in the 1840s, he told Owen that the skeletons were so well preserved that he expected to find living examples in Australia's then-unexplored central regions.

• The bulk of the fossils discovered come from diprotodon that died as a result of drought. Hundreds of people were discovered in Lake Callabonna, for example, with well-preserved lower bodies but crushed and twisted heads. Several family groups are said to have been entangled in the mud when walking the drying lake bed. Other discoveries include age groups of young or elderly animals who are the first to perish during a drought.

• An important community of around 40 was discovered in Eulo, southwest Queensland, in 2012.

Identification of the Diprotodon

• The diprotodon was found to be as close to a giant wombat. Diprotodon was a herbivore animal and like all the large living herbivores, Diprotodon was found to be heavily built and had a large bellied quadruped. Its colossal skull, like that of other diprotodontids, was light and brimmed with air gaps. Because of the retracted location of the nasal bones, some scientists say Diprotodon had a short trunk (bones of the snout).

• The length of the skull of an adult Diprotodon ranged between 66 cm to 1m. The cranial profile is elongated and short as seen from the side. Laterally, the zygomatic arch and flare. It had wombat-like feet that bent inwards, giving it a pigeon-toed appearance. It had powerful paws on its front feet and a pouch that opened backwards.

• There were large endocranial sinus cavities in the skull of Diprotodon which resulted in the separation of the relatively smaller cranial vault from the outer part of the skull. These decrease load burden while greatly lightening the skull and creating vast areas for muscle attachment.

• Both members of the order Diprotodontia have two forwardly oriented lower incisors, as did Diprotodon in which 'di' means 'twice,' 'proto' means 'first,' and 'odon' means 'tooth' in the  Greek language. In addition to the two lower incisors, each jaw has three upper incisors. Each jaw contains four wide, simple molars, each with two transverse crests (lophs). The third premolar is the only one that has survived; the rest have all been lost.

• Diprotodon is a member of the Diprotodontinae subfamily, which differs from the Zygomaturinae subfamily in part by possessing a simplified third premolar with a horseshoe-shaped crest in occlusal vision. The molars of Diprotodon are also higher crowned, more rectangular, and bigger than those of Zygomaturus.

• Diprotodon's limbs were powerful and pillar-like. The bones in the upper limbs were longer than those in the lower limbs. Diprotodon's characteristic feet were unusually short for its height and inverted, as in wombats hence the name giant womb

• Diprotodon's characteristic feet were unusually short for its height and inverted, as in wombats hence the name giant wombats. Other diprotodontian marsupials and bandicoots have syndactylous (joined) digits II-III. While huge, Diprotodon was smaller than either a hippopotamus or a rhinoceros, with a length of just under 4 meters and a weight of up to 2800 kilograms.

• The image given below shows the descriptive features of a diprotodon

Habitat of the Australian diprotodon

• Diprotodon usually preferred semi-arid plains, savannahs, and the open woodlands and it is believed that they were absent from the hilly, forested coastal regions where only a few diprotodontids were found as it was largely populated by, Zygomaturus.

• Diprotodon has been found in a few coastal locations in South Australia, including Naracoorte Caves and Kangaroo Island. However, during the Pleistocene, when sea levels were lower, these regions may have been farther from the ocean.

• Australian Pleistocene ecosystems evolved over time as a result of climate change. At this time, dry, windy conditions alternated with more equable ones, and sea levels were usually much smaller than they are today due to polar ice. Droughts may have made most of inland Australia uninhabitable and hundreds of people were discovered stranded in the mud at the center of Lake Callabonna in northern South Australia as the lakebed dried out. One analysis of Diprotodon habitat on the Darling Downs in Queensland discovered that as the air grew drier, areas once covered in woodlands, vine thickets, and scrublands gave way to grasslands.

Distribution of the Diprotodon

• The Diprotodon was called the giant wombat and it was found to be distributed all across the mainlands of Australia around 1.6 million and 45,000 years ago in a period known as the Pleistocene. During the period of the Pleistocene, the Diprotodon was a part of the group of megafauna that basically is said to have ruled Australia and this group included animals such as Giant Kangaroos, huge snakes which would make the python look like a newly hatched reptile from an egg, and marsupial lions. 

• The Darling Downs in southeastern Queensland; Wellington Caves, Tambar Springs, and Cuddie Springs in New South Wales; Bacchus Marsh in Victoria; and Lake Callabonna, Naracoorte Caves, and Burra in South Australia are only a few of the places where Diprotodon has been discovered. New Guinea, southwestern Western Australia, the Northern Territory, and Tasmania have no Diprotodon (although it was present on King Island).

Feeding and Diet Habits of the Diprotodon

• All the Diprotodon were considered to be herbivores as they used to feed on the shrubs and the forbs. The scientist was able to determine the eating habits of the Diprotodon from the discovered fossils which were found all across Australia. The fossils of saltbush were found in the abdominal area of one skeleton from Lake Callabonna. Diprotodon may have consumed up to 150 kilograms of vegetation a day. Its chisel-like incisors may have been used to pull plants out of the ground.

• Diprotodon did not travel in huge herds as is often portrayed. Big communities of marsupials are uncommon. Smaller family groups were likely attracted in masses to the drying waterhole at Lake Callabonna, as shown by the vast numbers of people found there.

Life Cycle History of the Diprotodon

• In Diprotodon the males were considered to be larger than the females and as a result of that, it is believed that there was a high degree of sexual dimorphism between the males and females. Breeding is commonly polygynous in living sexually dimorphic mammals. Diprotodon may have followed a similar breeding strategy.

• There is some evidence of Diprotodon being preyed upon or scavenged by the Pleistocene'marsupial lion,' Thylacoleo Carnifex: a forelimb bone (ulna) was discovered near Glen Innes, New South Wales, with deep, blade-like tooth marks that approximate those of Thylacoleo (whose teeth were also found at the site).

Fossils Description of the Diprotodon

• There were many fossils that were found of the Diprotodon all across Australia. Late Pliocene deposits at Lake Kanunka, South Australia, and Fisherman's Cliff, New South Wales, contain the genus Diprotodon's oldest fossils. Diprotodon optatum lived during the Pleistocene epoch and died out around 25,000 years ago. Hair and foot impressions, as well as complete skulls and skeletons, have been discovered. A trackway has also been preserved at Lake Callabonna.

• The skeleton of a very large human discovered at Tambar Springs in NSW and excavated by Australian Museum palaeontologists is the most complete specimen. It is currently on display at the Coonabarabran Visitor Centre in central New South Wales as part of the Australian Museum's fossil collection. A thin, square hole on one rib has been tentatively identified as being formed by a spear when the bone was still new. This is one of the few items of evidence that suggests Diprotodon was hunted by humans.

Extinction of the Diprotodon

• Few of the modern researchers have argued that Diprotodon along with other Australian megafauna became extinct shortly after the Humans arrived in Australia which was about fifty thousand years ago. Many of the animals of the Australian Pleistocene have no confirmed record over the last 100,000 years, and there is not enough evidence to definitively ascertain the period of extinction for many of them. The researchers believe that climatic stress caused much of the extinctions to occur in stages during the late Middle Pleistocene and early Late Pleistocene, prior to human arrival.

• Diprotodont remains from many locations, including Tambar Springs, Trinkey, and Lime Springs, indicate that Diprotodon lived even longer, into the Holocene, according to several earlier scholars, including Richard Wright. 

• Lesley Head and Judith Field, two more recent scholars, favor an extinction date of 28,000 to 30,000 years ago, implying that humans coexisted with Diprotodon for 20,000 years. 

• Opponents of "late extinction" hypotheses, on the other hand, have interpreted late dates based on indirect dating techniques as objects arising from the redeposition of skeletal material into more modern strata, and recent direct dating findings obtained through modern technology have continued to support this interpretation.

• In conclusion, three theories have been proposed to explain the mass extinction of the Diprotodon. Climate change, Hunting done by the human’s and human land management have been considered to be the possible causes of the mass extinction of the Diprotodon.

Did You Know?

Here are a Few of the Amazing Facts About the Diprotodon:

1. The Diprotodon was considered to be the largest marsupial that ever lived. During the Pleistocene epoch, marsupials reached massive proportions. Diprotodon was the tallest pouched animal that ever existed, measuring 10 feet long from snout to tail and weighing up to three tonnes. It dwarfed both the colossal short-faced kangaroo and the marsupial lion. In reality, the rhinoceros-sized giant wombat was one of the Cenozoic Era's largest plant-eating mammals, whether placental or marsupial.

2. Australia is a massive continent with a vast interior that remains a mystery to its current human inhabitants. Diprotodon fossils have been found across Australia, from New South Wales to Queensland, and as far north as the "Far North" area of South Australia. The giant wombat's continental range is close to that of the still-living eastern grey kangaroo. The eastern grey kangaroo can reach a maximum weight of 200 pounds and is a mere shadow of its prehistoric relative.

3. Australia, despite its size, can be harshly dry, just as much as it was two million years ago as it is today. Many Diprotodon fossils have been found around salt-covered lakes that are diminishing. The giant wombats were apparently migrating in search of water, and some of them perished as they smashed through the crystalline crust of lakes. Drought-related fossil findings of grouped Diprotodon juveniles and older herd members may also be explained by extreme drought conditions.

4. The male Diprotodon was considered to be larger than the females. During the course of the 19th century, many palaeontologists have discovered half-dozen separate Diprotodon species which have been differentiated from one another based on their size. These differences in size are now referred to as sexual division rather than speciation. The males of one genus of giant wombat (Diprotodon optatum) were larger than the females at all stages of development.

5. According to palaeontologists, the first humans arrived in Australia about 50,000 years ago. About the fact that these early humans may have been concentrated along the Australian coast, they would have come into contact with the giant wombat on occasion and soon realized that a single three-ton herd alpha could sustain an entire tribe for a week.

6. It appears to be a foregone conclusion that Diprotodon was hunted to extinction by early humans since it vanished around 50,000 years ago. However, palaeontologists disagree, with some claiming that climate change and deforestation were to blame for the giant wombat's demise. When Diprotodon's territory was eroded by gradual warming, its accustomed foliage withered, and the few remaining herd members were quickly picked off by hungry Homo sapiens, it was most likely a mixture of all three.