Diprotodon on:
[Wikipedia]
[Google]
[Amazon]
''Diprotodon'' (
In 1830, bushman George Ranken found a diverse fossil assemblage while exploring Wellington Caves, 
Huge assemblages of rather complete ''Diprotodon'' fossils have been unearthed in dry lake- or riverbeds, the largest from Lake Callabonna. Fossils were first noticed here by an aboriginal stockman working on a sheep property just east. The owners, the Ragless brothers, notified the
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
: "two protruding front teeth") is an extinct genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of marsupial
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a ...
from the Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
of Australia, containing one species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
, ''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 massive fossils were first unearthed in 1830 in Wellington Caves, New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
, before any serious scientists were active on the continent, and were variably guessed to belong to rhino
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...
s, elephant
Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae ...
s, hippo
The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extant ...
s, or dugong
The dugong (; ''Dugong dugon'') is a marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. It is the only living representative of the once-diverse family Dugongidae; its closest m ...
s. ''Diprotodon'', formally described by Sir Richard Owen
Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils.
Ow ...
in 1838, was the first named Australian fossil creature, and set Owen on a path to becoming the foremost authority of his time on other marsupials and Australian megafauna
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 ...
so enigmatic to European science.
''Diprotodon'' is the largest known marsupial to have ever lived, far dwarfing its closest living relatives, wombats and koala
The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the w ...
s. It grew as large as at the shoulders, over from head to tail, and possibly almost in weight. Females were much smaller than males. It supported itself on elephant-like legs to traverse long distances, and was able to colonise most of Australia. The digits were weak, and most of the weight was probably borne on the wrists and ankles. The hindpaws angled inward at 130°. Its jaws may have produced a prodigious bite force
Bite force quotient (BFQ) is a numerical value commonly used to represent the bite force of an animal, while also taking factors like the animal's size into account.
The BFQ is calculated as the regression of the quotient
In arithmetic, a ...
of at the long and ever-growing incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
s, and over at the last molar. Such power would have permitted it to eat vegetation in bulk, crunching and grinding on mixed browse with its bilophodont
The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, ...
teeth.
It is the only known marsupial (and metatherian) identified to make seasonal migrations, trekking through a wide range of habitats in large (usually female) herds to search out food and water. Walking speed could have been about . ''Diprotodon'' may have formed polygynous societies, possibly using its powerful incisors to battle for mates or fend off predators, namely the largest known marsupial carnivore, ''Thylacoleo carnifex
''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest mammalian pred ...
''. Being a marsupial, ''Diprotodon'' raised a joey in a pouch on its belly, probably one facing backwards like a wombat.
''Diprotodon'' went extinct about 40,000 years ago as part of the Quaternary extinction event
The Quaternary period (from 2.588 ± 0.005 million years ago to the present) has seen the extinctions of numerous predominantly megafaunal species, which have resulted in a collapse in faunal density and diversity and the extinction of key ecolog ...
, along with every other Australian creature over , possibly caused by the extreme drought conditions, as well as pressure from the first Aboriginal Australian
Aboriginal Australians are the various Indigenous peoples of the Australian mainland and many of its islands, such as Tasmania, Fraser Island, Hinchinbrook Island, the Tiwi Islands, and Groote Eylandt, but excluding the Torres Strait Isl ...
s who had been sharing the continent with the megafauna for about 20,000 years. Conversely, there is no solid direct evidence of Australian aboriginals and ''Diprotodon'' (or any Pleistocene megafauna) interacting at all. ''Diprotodon'' has been conjectured to be the subject of some aboriginal mythological figures (most notably, the bunyip
The bunyip is a creature from the aboriginal mythology of southeastern Australia, said to lurk in swamps, billabongs, creeks, riverbeds, and waterholes.
Name
The origin of the word ''bunyip'' has been traced to the Wemba-Wemba or Wergaia ...
) and aboriginal rock art
Indigenous Australian art includes art made by Aboriginal Australian and Torres Strait Islander peoples, including collaborations with others. It includes works in a wide range of media including painting on leaves, bark painting, wood carving ...
works, but these are unconfirmable.
Research history
In 1830, bushman George Ranken found a diverse fossil assemblage while exploring Wellington Caves, New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
. This was the first major site of extinct Australian megafauna
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 ...
. They were excavated when Ranken returned later in a formal expedition headed by Major Thomas Mitchell.
At the time these massive fossils were discovered, there were no serious scientists in Australia. It was generally guessed that the fossil assemblage represents rhino
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...
s, elephant
Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae ...
s, hippo
The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extant ...
s, or dugong
The dugong (; ''Dugong dugon'') is a marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. It is the only living representative of the once-diverse family Dugongidae; its closest m ...
s, but they were not formally described until Mitchell, while in England publishing his journal, brought them to his former colleague Sir Richard Owen in 1837. In 1838, while studying a piece of a right mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
with an incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
, Owen compared the tooth to that of a wombat or a hippo, and designated it as a new genus in a letter to Mitchell, as ''Diprotodon''. Mitchell published the correspondence in his journal. Owen formally described ''Diprotodon'' in volume 2 without mentioning a species, but in volume 1, he listed the name ''Diprotodon optatum'', making that the type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
. ''Diprotodon'' means "two protruding front teeth". It was the first ever Australian fossil mammal described. In 1844, Owen replaced the name ''D. optatum'' with "''D. australis''". Owen only used ''optatum'' the one time, and the acceptance of its apparent replacement "''australis''" has historically varied widely.
In 1843, Mitchell was sent more ''Diprotodon'' fossils from the recently settled Darling Downs
The Darling Downs is a farming region on the western slopes of the Great Dividing Range in southern Queensland, Australia. The Downs are to the west of South East Queensland and are one of the major regions of Queensland. The name was general ...
, and relayed them to Owen. Owen believed ''Diprotodon'' was an elephant related to or synonymous with ''Mastodon
A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of th ...
'' or '' Deinotherium'', having interpreted the incisors as tusks, as well as comparing the flattening (anteroposterior compression) of the femur to the condition in elephants and rhinos, and the raised ridges of the molar to the grinding surfaces of elephant teeth. Later that year, he formally synonymised ''Diprotodon'' with ''Deinotherium'' as "''Dinotherium Australe''", which he recanted in 1844 after German naturalist Ludwig Leichhardt pointed out that the incisors clearly belong to a marsupial
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a ...
. Owen, nonetheless, still classified the molars from Wellington as "''M. australis''". He also continued to describe ''Diprotodon'' as likely elephantine. In 1847, a nearly complete skull and skeleton was recovered from the Darling Downs, which confirmed this characterisation. The massive skeleton, while on public display in Sydney, attracted quite an audience. Leichhardt believed the animal was aquatic and suggested in 1844 that it might still be alive in an undiscovered tropical area towards the interior, but as the European land exploration of Australia
European land exploration of Australia deals with the opening up of the interior of Australia to European settlement which occurred gradually throughout the colonial period, 1788–1900. A number of these explorers are very well known, such as B ...
progressed, he became certain it was extinct. Owen would go on to be the foremost authority of Australian palaeontology of his time, mostly working with marsupials.
Huge assemblages of rather complete ''Diprotodon'' fossils have been unearthed in dry lake- or riverbeds, the largest from Lake Callabonna. Fossils were first noticed here by an aboriginal stockman working on a sheep property just east. The owners, the Ragless brothers, notified the South Australian Museum
The South Australian Museum is a natural history museum and research institution in Adelaide, South Australia, founded in 1856 and owned by the Government of South Australia. It occupies a complex of buildings on North Terrace in the cultu ...
who hired Australian geologist Henry Hurst, who reported an enormous wealth of fossil material. He was given £250 in 1893 to excavate the site, and turned over 360 ''Diprotodon'' individuals over a few acres, and more were uncovered pretty soon after excavation was restarted in the 1970s. Multiple herds of these animals at different times probably got stuck in the mud during their crossing while the water was low during dry season
The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The te ...
s.
In addition to ''D. optatum'' and "''D. australis''", several other species were erected through the 19th century because adult ''Diprotodon'' specimens come in two distinct size ranges. In their 1975 review of Australian fossil mammals, Australian palaeontologists J. A. Mahoney and William David Lindsay Ride did not ascribed this to sexual dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...
because males and females among modern wombat and koala species (its closest living relatives) are skeletally indistinguishable, so they assumed the same would have been true for extinct relatives, including ''Diprotodon''.
These other species are:
*"''D. annextans''", erected in 1861 by Irish palaeontologist Frederick McCoy
Sir Frederick McCoy (1817 – 13 May 1899), was an Irish palaeontologist, zoologist, and museum administrator, active in Australia. He is noted for founding the Botanic Garden of the University of Melbourne in 1856.
Early life
McCoy was the so ...
based on some teeth and a partial mandible near Colac, Victoria
Colac is a small city in the Western District of Victoria, Australia, approximately 150 kilometres south-west of Melbourne on the southern shore of Lake Colac.
History
For thousands of years clans of the Gulidjan people occupied the region o ...
; the name may be a typo of ''annectens'' which means linking or joining, because the species combines traits from ''Diprotodon'' and '' Nototherium'';
*"''D. minor''", erected in 1862 by Thomas Huxley
Thomas Henry Huxley (4 May 1825 – 29 June 1895) was an English biologist and anthropologist specialising in comparative anatomy. He has become known as "Darwin's Bulldog" for his advocacy of Charles Darwin's theory of evolution.
The stor ...
based on a partial palate
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity.
A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separ ...
; in 1991, Australian palaeontologist Peter Murray suggested classifying large specimens as ''D. optatum'' and smaller ones as "''D. minor''";
*"''D. longiceps''", erected in 1865 by McCoy as a replacement for "''D. annextans''";
*"''D. bennettii''", erected in 1873 by German naturalist Gerard Krefft based on a nearly complete mandible collected by naturalists George Bennet and Georgina King near Gowrie, New South Wales;
*and "''D. loderi''", erected in 1873 by Krefft based on a partial palate
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity.
A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separ ...
collected by Andrew Loder near Murrurundi
Murrurundi( ), is a rural town located in the Upper Hunter Shire, in the Upper Hunter region of New South Wales, Australia.
Murrurundi is situated northwest by road from Newcastle and north from Sydney. At the the town had a population of ...
, New South Wales.
In 2008, Australian palaeontologist Gilbert Price opted to recognise only one species, ''D. optatum'' based most notably on a lack of dental differences among these supposed species, and suggested that it was likely that ''Diprotodon'' was indeed sexually dimorphic, with the male probably being the larger form.
Classification
Phylogeny
''Diprotodon'' is a marsupial in the orderDiprotodontia
Diprotodontia (, from Greek "two forward teeth") is the largest extant order of marsupials, with about 155 species, including the kangaroos, wallabies, possums, koala, wombats, and many others. Extinct diprotodonts include the hippopotamus-sized ...
, suborder Vombatiformes
The Vombatiformes are one of the three suborders of the large marsupial order Diprotodontia. Seven of the nine known families within this suborder are extinct; only the families Phascolarctidae, with the koala, and Vombatidae, with three extan ...
(wombats and koalas), infraorder
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
Vombatomorphia (wombats and allies). It is unclear how different groups of vombatiformes are related to each other as the most completely known members, living or extinct, are exceptionally derived (highly specialised forms which are quite different from their last common ancestor
In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...
).
In 1872, American mammalogist Theodore Gill
Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist and librarian.
Career
Born and educated in New York City under private tutors, Gill early showed interest in natural histo ...
erected the superfamily Diprotodontoidea and family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Diprotodontidae to house ''Diprotodon''. New species were added to both groups in subsequent years. By the 1960s, the first diprotodontoids dating to before the Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Ruben A. Stirton subdivided Diprotodontoidea into one family, Diprotodontidae, with four subfamilies: Diprotodontinae (containing ''Diprotodon'' among others), Nototheriinae, Zygomaturinae, and Palorchestinae. In 1977, Australian palaeontologist Michael Archer synonymised Nototheriinae with Diprotodontinae, and in 1978, Archer and Australian palaeontologist Alan Bartholomai elevated Palorchestinae to family level as Palorchestidae, leaving Diprotodontoidea with two families (Diprotodontidae and Palorchestidae), and Diprotodontidae with two subfamilies (Diprotodontinae and Zygomaturinae).
Diprotodontoidea family tree according to Australian palaeontologists Karen H. Black and Brian Mackness, 1999 (left), and Vombatiformes family tree according to Beck ''et al.'' 2020 (right):
Diprotodontidae is the most diverse family in Vombatomorphia, better adapted to the spreading dry and open landscapes over the last tens of millions of years than other groups in the infraorder (living or extinct). Similarly, ''Diprotodon'' has been found in every Australian state, making it the most widespread Australian megafauna in the fossil record. The oldest vombatomorph (and vombatiform) is '' Mukupirna'', identified in 2020 from Oligocene deposits of the South Australian Namba Formation dating to 26–25 million years ago. The group probably evolved much earlier, since ''Mukupirna'' was already differentiated as a closer relative to wombats than other vombatiformes; and attained a massive size of roughly , whereas the last common ancestor of vombatiformes was probably a small creature.
Both diprotodontines and zygomaturines were both apparently quite diverse over the
Like kangaroos and wombats, there is a gap in between the jointing of the
The
''Diprotodon'' probably had 13 dorsal vertebrae and 14 pairs of closely-spaced ribs. Like many other mammals, the dorsals initially decrease in breadth and then expand before connecting to the
''Diprotodon'' is the largest known marsupial to have ever lived. The bigger ''Diprotodon'' skeletons measure at the shoulders, and from head to tail. Accounting for cartilagenous intervertebral discs, ''Diprotodon'' may have been 20% longer than the reconstructed skeletons, exceeding .
As researchers were formulating predictive body mass equations for fossil species, efforts were largely constrained to
Like modern megaherbivores, most evidently the African elephant, the Pleistocene Australian megafauna likely had a profound effect on the vegetation, limiting the spread of forest cover and woody plants. Carbon isotope analysis suggests ''Diprotodon'' fed on a broad range of foods, and, like kangaroos, was consuming both C3 (well-watered trees, shrubs, and grasses) and C4 (arid grasses) plants. Still, the low seasonal δ13C values (its carbon isotope ratio remained about the same in both winter and summer, so it ate the same proportion of C3 and C4 plants regardless of their seasonal abundance) indicate that ''Diprotodon'' was a selective eater, at least more so than the modern wombat. The fossilised gut contents (incompletely digested) of one 53,000 year old individual from Lake Callabonna shows its last meal consisted of young leaves, stalks, and twigs.
The molars of ''Diprotodon'' are a simple bilophodont shape. Kangaroos use their bilophodont teeth to grind low-fibre (not too tough) plants as a browser, as well as grass as a grazer. Kangaroos which predominantly graze have specialised molars to resist the abrasiveness of grass, but such adaptations are not exhibited in ''Diprotodon'', so ''Diprotodon'' may have had a mixed diet similar to a browsing
In 2017, Price and colleagues determined that ''Diprotodon'' made seasonal migrations, probably in search of food or watering holes. Price and colleagues did this by measuring the strontium isotope ratio (87Sr/86Sr) at various points along the ''Diprotodon'' incisor QMF3452 from the Darling Downs, and matching those ratios to the ratios of sites across that region. This individual appears to have been following the
The locomotion of an extinct animal can be inferred using
Given its massive size, ''Diprotodon'' would have been a tough adversary for native carnivores. It contended with the largest known marsupial predator, ''Thylacoleo carnifex'', and while ''Diprotodon'' fossils gnawed or bitten by ''T. carnifex'' have been identified, it is unclear if the marsupial predator was powerful enough to take down an animal surpassing . Given that the modern jaguar, at half the size of ''T. carnifex'', can bring down a bull, it is not impossible that ''T. carnifex'' could have killed smaller sized ''Diprotodon''. Similar to recent kangaroos with thylacines or
In 2005, American geologist Gifford Miller noticed that fire abruptly becomes much more common about 45,000 years ago, which he ascribed to aboriginal fire-stick farmers, who would have regularly started controlled burns to clear highly productive forests and grasslands. He believed this radically altered the vegetational landscape, and promulgated the expanse of the modern day fire-resilient scrub, at the expense of the megafauna. Many subsequent studies have had trouble firmly linking controlled burns and major ecological collapse. The frequency of fire could have also increased as a consequence of megafaunal extinction, as total plant consumption plummeted, leading to faster fuel buildup.
In 2017, the human-occupied Madjedbebe rockshelter by the northern Australian coast was dated to about 65,000 years, which meant that humans and megafauna had coexisted for over 20,000 years, casting strong doubt on the unilateral role of human activity in megafaunal extinction. Further, in the 2010s, several ecological studies were published in support of major drought conditions coinciding with the final megafaunal extinctions. Therefore, their demise may have been the result of a combination of ecological turmoil, human hunting, and human-driven landscape changes.
When the first massive fossils were dug up in Australia, it was not clear what animals they might have represented as there were no serious scientists on the continent, but locals guessed some may represent rhinos or elephants. The colonists, most vocally Reverend John Dunmore Lang, forwarded these fossils as evidence of the Genesis flood narrative. The aborigines also attempted to fit the finds into their own religious ideas, quickly associating ''Diprotodon'' with the
Evolution
Diprotodontidae is the most diverse family in Vombatomorphia, better adapted to the spreading dry and open landscapes over the last tens of millions of years than other groups in the infraorder (living or extinct). Similarly, ''Diprotodon'' has been found in every Australian state, making it the most widespread Australian megafauna in the fossil record. The oldest vombatomorph (and vombatiform) is '' Mukupirna'', identified in 2020 from Oligocene deposits of the South Australian Namba Formation dating to 26–25 million years ago. The group probably evolved much earlier, since ''Mukupirna'' was already differentiated as a closer relative to wombats than other vombatiformes; and attained a massive size of roughly , whereas the last common ancestor of vombatiformes was probably a small creature.
Both diprotodontines and zygomaturines were both apparently quite diverse over the Late Oligocene
The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/ Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...
to Early Miocene
The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages.
The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...
roughly 23 million years ago (though the familial and subfamilial classifications of diprotodontoids from this time period is debated). Compared to zygomaturines, diprotodontines were rare during the Miocene, the only identified genus being '' Pyramios''. By the Late Miocene, diprotodontians became the most common marsupial order in fossil sites, a dominance which indures to
present day; at this point, the most prolific diprotodontians were diprotodontids and kangaroos. Diprotodontidae also began a gigantism trend, along with several other marsupials, probably a response to the lower quality plant foods available in a drying climate, requiring them to consume much more. Gigantism appears to have evolved six time independently among the vombatiform lineages. Diprotodontine diversity returned in the Pliocene, and Diprotodontidae reached peak diversity with seven genera, coinciding with the spread of open forests. In 1977, Archer suggested that ''Diprotodon'' directly evolved from the smaller '' Euryzygoma'', which has been discovered in Pliocene deposits of eastern Australia predating 2.5 million years ago.
In general, there is poor resolution on the ages of Australian fossil sites, and while the geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is ...
of ''Diprotodon'' is one of best for Australian megafauna, it is still quite incomplete and the majority of remains sit undated. The earliest (indirectly dated) ''Diprotodon'' fossils were reported by Price and Australian palaeontologist Katarzyna Piper from the Nelson Bay Formation at Nelson Bay, New South Wales
Nelson Bay is a significant township of the Port Stephens local government area in the Hunter Region of New South Wales, Australia. It is located on a bay of the same name on the southern shore of Port Stephens about by road north-east of N ...
, which dates to 1.77 million to 780,000 years ago during the Early Pleistocene. The remains are notably smaller than Late Pleistocene ''Diprotodon'' by 8–17%, but they are otherwise indistinguishable. The oldest directly dated fossils come from the Boney Bite site at Floraville, New South Wales. They were deposited approximately 340,000 years ago during the Middle Pleistocene
The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. Th ...
based on U-series dating and luminescence dating of quartz
Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
and orthoclase
Orthoclase, or orthoclase feldspar ( endmember formula K Al Si3 O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture," because its two cleavage planes are at right angles ...
. Floraville is the only identified Middle Pleistocene site in tropical northern Australia. Beyond these, almost all dated material comes from Marine Isotope Stage 5
Marine Isotope Stage 5 or MIS 5 is a marine isotope stage in the geologic temperature record, between 130,000 and 80,000 years ago. Sub-stage MIS 5e, called the Eemian or Ipswichian, covers the last major interglacial period before the Holocene, w ...
(MIS5) or younger (after 110,000 years ago) during the Late Pleistocene.
Description
Skull
''Diprotodon'' has a long and narrow skull. Like other marsupials, the top of the skull of ''Diprotodon'' is flat or depressed over the small braincase, as well as the sinuses of thefrontal bone
The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...
. Like many other giant vombatiformes, the frontal sinus
The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle ...
es are extensive; in a specimen from Bacchus Marsh, they take up —roughly 25% of skull volume—whereas the brain only occupies —only 4% skull volume. Marsupials tend to have smaller brain to body mass ratios than placental
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...
mammals, becoming more disparate the bigger the animal, which could be a response to conserve energy (as the brain is a calorically expensive organ) or is proportional to the maternal metabolic rate (which is much less in marsupials since they do not have to gestate for as long). The expanded sinuses increase the surface area available for the temporalis muscle
In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomati ...
to attach (important for biting and chewing) to compensate for a deflated braincase as a result of a proportionally smaller brain. They may have also helped dissipate stresses produced by biting more efficiently across the skull.
The occipital bone, the back of the skull, slopes forward at a 45° angle, as opposed to most modern marsupials where it is vertical. The base of the occipital is heavily thickened. The occipital condyle
The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra.
The condyles are oval or reniform (kidney-shaped) in shape, and their anteri ...
s (a pair of bones which connect the skull with the vertebral column
The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordate ...
) are semi-circle shaped, with the bottom half being narrower than the top. The inner border (which forms the foramen magnum, where the spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...
feeds through) is thin and well-defined. The top margin of the foramen magnum is somewhat flattened rather than arched. The foramen expands backwards towards the inlet, especially vertically, and is more reminiscent of a short neural canal
In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural fold become elevated, ...
(the tube running through a vertebral centrum where the spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...
passes through) than a foramen magnum.
There is a sagittal crest extending across the midline of the skull from the supraoccipital (the top of the occipital bone) to the interorbital region (between the eyes on the top of the head). The orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...
(eye socket) is small and oval-shaped vertically. The nasal bones slightly curve upwards until near their endpoint, where they begin to curve down, giving the bones somewhat of an S-shaped profile. Like many marsupials, most of the nasal septum
The nasal septum () separates the left and right airways of the nasal cavity, dividing the two nostrils.
It is depressed by the depressor septi nasi muscle.
Structure
The fleshy external end of the nasal septum is called the columella or co ...
is made of bone rather than cartilage. The nose would have been quite mobile. The height of the skull from the peak of the occipital bone to the end of the nasals is strikingly almost uniform, but the end of the nasals is the tallest point. The zygomatic arch (cheek bone) is strong and deep like in kangaroos, but unlike koalas or wombats, and also extends all the way from the supraoccipital.
Jaws
Like kangaroos and wombats, there is a gap in between the jointing of the palate
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity.
A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separ ...
(roof of the mouth) and the maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
(upper jaw) behind the last molar, which is filled by the medial pterygoid plate
The pterygoid processes of the sphenoid (from Greek ''pteryx'', ''pterygos'', "wing"), one on either side, descend perpendicularly from the regions where the body and the greater wings of the sphenoid bone unite.
Each process consists of a me ...
. This would have been the insertion for the medial pterygoid muscle relevant to closing the jaw. Like many grazers, the masseter muscle
In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it ...
(also responsible for closing the jaw) seems to have been the dominant jaw muscle, and a probable large temporal muscle compared to the lateral pterygoid muscle may indicate, unlike wombats, a limited range of jaw motion side-to-side (i.e., ''Diprotodon'' would have been better at crushing rather than grinding food). The insertion of the masseter is placed forwards, in front of the orbits, which could have allowed better control over the incisors. Overall, ''Diprotodon'' chewing strategy appears to align more with kangaroos than wombats, with a powerful vertical crunch followed by a transverse grinding motion.
Like other marsupials, the ramus of the mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
(the portion that goes up to connect with the skull) angles inward. The condyloid process
The condyloid process or condylar process is the process on the human and other mammalian species' mandibles that ends in a condyle, the mandibular condyle. It is thicker than the coronoid process of the mandible and consists of two portions: the ...
(which connects the jaw to the skull) is similar to that of a koala. The ramus is straight and extends almost vertically, thickening as it approaches the body of the mandible (where the teeth are). The depth of the body of the mandible increases somewhat from the last to the first molar. The mandibular symphysis (which fuses the two halves of the mandible) is strong, beginning at the frontmost end of the third molar; this would prevent either half of the mandible from moving independently of the other, unlike kangaroos which use this ability to better control their incisors.
Teeth
The dental formula
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...
of ''Diprotodon'' is , with, in each half of either jaw, three incisors in the upper and one in the lower jaw; no canines; and one premolar and four molars in both jaws. There is a long diastema
A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition ...
(gap) separating the incisors from the molars.
The incisors are chisel-like (scalpriform). The first incisors in both jaws grew continuously throughout the animal's life, like wombats and rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...
s, but the other two upper incisors did not. This combination is not seen in any living marsupial. The cross-section of the upper incisors is circular. In one old male specimen, the first upper incisor measures of which is within the tooth socket; the second is where is in the socket; and the exposed part of the third is . The first incisor is convex and curves outwards, but the other two are concave. The lower incisor has a faint upward curve but is otherwise straight, and it has an oval cross-section. In the same old male specimen, it measures of which is inside the socket.
The premolars and molars are bilophodont
The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, ...
, and each features two distinct lophs (ridges). The premolar is triangular and about half the size of the molars. The necks of the lophs are coated in cementum
Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.Illustrated Dental Embryology, Histology, ...
like kangaroos. Unlike kangaroos, there is no connecting ridge between the lophs. The peaks of these lophs have a thick enamel coating, which thins towards the base. This could wear away with use and expose the dentine
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by e ...
layer, and beneath that osteodentine. Like the first premolar of other marsupials, the first molar of ''Diprotodon'' and wombats is the only tooth that is replaced.
Vertebrae
''Diprotodon'' had five cervical (neck) vertebrae. Theatlas
An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth.
Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geograp ...
, the first cervical (C1), has a pair of deep cavities for insertion of the occipital condyles. The diaphophyses (an upward-angled projection on either the side of the vertebra) of the atlas are relatively short and thick, and overall resemble those of wombats and koalas. The articular surface (the part that joints to another vertebra) of the axis
An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to:
Mathematics
* Axis of rotation: see rotation around a fixed axis
* Axis (mathematics), a designator for a Cartesian-coordinat ...
(C2) is slightly concave on the front side, and flat on the back side. Like kangaroos, the axis has a low subtriangular hypophysis (projecting vertically from the underside of the vertebra) and a proportionally long odontoid (a projection from the axis which fits into the atlas), but the neural spine (which project vertically the topside of the vertebra) is more forwards. The remaining cervicals lack a hypophysis. Like kangaroos, C3 and C4 have a shorter and more compressed neural spine, which is supported by a low ridge along its midline in the front and the back. The neural spine of C5 is narrower but thicker, and is supported by stronger though shorter ridges.
''Diprotodon'' probably had 13 dorsal vertebrae and 14 pairs of closely-spaced ribs. Like many other mammals, the dorsals initially decrease in breadth and then expand before connecting to the lumbar vertebra
The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse ...
e. The front dorsals unusually match the short proportions of the cervicals, and the articular surface is flat. At the beginning of the series, the neural spine is broad and angled forward, and is also supported by a low ridge along its midline in the front and the back. Later on, the neural spine is angled backwards, and bifurcates (splits into two). Among mammals, bifurcation of the neural spine is only seen in elephants and humans, and even then, only in a few of the cervicals, not in the dorsals. Compared to wombats and kangaroos, the neural arch is proportionally taller. Like in elephants, the epiphysial plates (growth plates) and the neural arch (where the neural spine is attached to) are anchylosed (very rigid in regard to the vertebral centrum), which serve to support the animal's immense weight.
Like most marsupials, ''Diprotodon'' likely had six lumbar vertebrae. They retain a proportionally tall neural arch, but not the diapophyses, though L1 can retain a small protuberance on one side where a diapophysis would be in a dorsal vertebra; this has been documented in kangaroos among other mammals. The length of each vertebra increases along the series, so the lumbar series may have bent downward.
Like other marsupials, ''Diprotodon'' had two sacral vertebrae. The base of the neural spines of these two were ossified
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...
(fused) together.
Limbs
Girdles
The general proportions of thescapula
The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eith ...
(shoulder blade) align more closely with more basal vertebrates such as monotremes, bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s, reptiles, or fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
, rather than marsupials or placentals. It is triangular and proportionally narrow, but unlike most mammals with a triangular scapula, the arm attaches to top of the scapula, and the subspinous fossa (the fossa below the spine of the scapula
The spine of the scapula or scapular spine is a prominent plate of bone, which crosses obliquely the medial four-fifths of the scapula at its upper part, and separates the supra- from the infraspinatous fossa.
Structure
It begins at the vertical ...
) increases towards the arm joint instead of decreasing. The glenoid cavity
The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from el, gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a sha ...
(where the arm connects) is oval shaped like in most mammals.
Unlike other marsupials, the ilia (the large wings of the pelvis) are lamelliform in being short and broad, and sporting a flat surface instead of a fossa (a depression). Lamelliform ilia have only been recorded in elephants, sloth
Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their l ...
s, and ape
Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...
s, though these groups all have a much longer sacral vertebra series (marsupials are restricted to two sacral vertebrae). Nonetheless, the ilia provided strong muscle attachments which were probably oriented and used much the same as in an elephant. The sacroiliac joint
The sacroiliac joint or SI joint (SIJ) is the joint between the sacrum and the ilium bones of the pelvis, which are connected by strong ligaments. In humans, the sacrum supports the spine and is supported in turn by an ilium on each side. Th ...
(where the pelvis connects to the spine) is at a 35° angle in reference to the long axis of the ilium. The ischia
Ischia ( , , ) is a volcanic island in the Tyrrhenian Sea. It lies at the northern end of the Gulf of Naples, about from Naples. It is the largest of the Phlegrean Islands. Roughly trapezoidal in shape, it measures approximately east to west ...
(which form part of the hip socket) are thick and rounded tailwards, but taper off and diverge towards the socket, unlike in kangaroos where the ischia proceed almost parallel to each other. They were not connected to the vertebra. The hip socket itself is well rounded and almost hemispherical.
Long bones
Unlike most marsupials, the humerus is rather straight (as opposed to S-shaped), and thetrochlea of the humerus
In the human arm, the humeral trochlea is the medial portion of the articular surface of the elbow joint which articulates with the trochlear notch on the ulna in the forearm.
Structure
In humans and apes it is trochleariform (or trochleiform), a ...
(at the elbow joint) is not perforated. The ridges for muscle attachments are poorly developed, which seems to have been compensated by the powerful forearms. Similarly, the condyles where the radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
and ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
(the forearm bones) connect maintain their rounded shape and are quite similarly sized, unusually reminiscent of the condyles between the femur
The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...
and the tibia
The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
and fibula
The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity i ...
in the leg of a kangaroo.
Like elephants, the femur of ''Diprotodon'' is straight, compressed anteroposteriorly (from headside to tailside), and the walls of the femur are prodigiously thickened, strongly constricting the medullary cavity
The medullary cavity (''medulla'', innermost part) is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow ( adipose tissue) is stored; hence, the medullary cavity is also known as the marrow cavity.
Located in the m ...
(where the bone marrow is). The proximal end (part closest to the hip joint) is notably long, broad, and deep. The femoral head
The femoral head (femur head or head of the femur) is the highest part of the thigh bone (femur). It is supported by the femoral neck.
Structure
The head is globular and forms rather more than a hemisphere, is directed upward, medialward, and a l ...
projects up far from the greater trochanter
The greater trochanter of the femur is a large, irregular, quadrilateral eminence and a part of the skeletal system.
It is directed lateral and medially and slightly posterior. In the adult it is about 2–4 cm lower than the femoral head.Stan ...
. Like kangaroos, the greater trochanter is split into two lobes. The femoral neck
The femoral neck (femur neck or neck of the femur) is a flattened pyramidal process of bone, connecting the femoral head with the femoral shaft, and forming with the latter a wide angle opening medialward.
Structure
The neck is flattened from ...
is roughly the same diameter has the femoral head. Like kangaroos, the condyle for the fibula is excavated out, but the condyle for the tibia is well rounded and hemispheric. Like many other marsupials, the tibia is twisted and the tibial malleolus
A malleolus is the bony prominence on each side of the human ankle.
Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the promine ...
(on the ankle) is reduced.
Paws
''Diprotodon'' has five digits on either paw. Like other plantigrade walkers (the paws were flat on the ground), the wrist and ankle would have been largely rigid and inflexible. The digits overall are proportionally weak, so the paws probably had a lot of padding in life. Similarly, the digits do not seem to have been engaged much in weight bearing. The forepaw was strong, and the shape of the wrist bones are quite similar to those kangaroos. Like other vombatiformes, themetacarpal
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ar ...
s are broadly similar to those of kangaroos and allies. The pisiform bone
The pisiform bone ( or ), also spelled pisiforme (from the Latin ''pisifomis'', pea-shaped), is a small knobbly, sesamoid bone that is found in the wrist. It forms the ulnar border of the carpal tunnel.
Structure
The pisiform is a sesamoid bone, ...
is enlarged, and takes up half the jointing surface of the ulna. The fifth digit on the forepaw is the largest.
The digits of the hindpaws turn inwards from the ankle at a 130° angle. The second and third metatarsals (the metatarsal
The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...
s connect the toes to the bones which connect to the ankle) are significantly reduced, which may mean these digits were syndactylous (fused) like in all modern diprotodontians. The first, fourth, and fifth digits are enlarged. The toes are each about the same length, except the fifth one which is much stouter.
Size
''Diprotodon'' is the largest known marsupial to have ever lived. The bigger ''Diprotodon'' skeletons measure at the shoulders, and from head to tail. Accounting for cartilagenous intervertebral discs, ''Diprotodon'' may have been 20% longer than the reconstructed skeletons, exceeding .
As researchers were formulating predictive body mass equations for fossil species, efforts were largely constrained to eutherian
Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials.
Eutherians are distinguished from noneutherians by various phenotypic tra ...
mammals as opposed to marsupials. The first attempt at estimating ''Diprotodon'' was Peter Murray in his 1991 review of the megafauna of Pleistocene Australia. He made an estimate of , though conceded it was probably not a very precise one. This made ''Diprotodon'' the largest herbivore in Australia. In 2001, Canadian biologist Gary Burness and colleagues did a linear regression between the largest herbivores and carnivores (living or extinct) from every continent (for Australia: ''Diprotodon'', ''Varanus priscus
Megalania (''Varanus priscus'') is an extinct species of giant monitor lizard, part of the megafaunal assemblage that inhabited Australia during the Pleistocene. It is the largest terrestrial lizard known to have existed, reaching an estimated ...
'', and ''Thylacoleo carnifex
''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest mammalian pred ...
'') vs. the landmass area of their continent, and another regression between the daily food intake of living creatures vs. the landmass of their continents. He calculated the food requirements of ''Diprotodon'' was 50–60% smaller than expected for Australia's landmass, which he believed was a result of a generally lower metabolism in marsupials compared to placentals (up to 20% lower) and sparser nutritious vegetation compared to other continents. That is, the maximum attainable body size is capped much lower than on other continents.
In 2003, Australian palaeontologist Stephen Wroe and colleagues took a more analytical approach to body mass than Murray's guesstimate. They made a regression between the minimum circumference of the femora and humeri of 18 quadrupedal marsupials and 32 placentals vs. body mass, and then input 17 ''Diprotodon'' long bones into their predictive model. The outputs ranged from , for a mean of , though Wroe conceded that reconstructing the weight of extinct creatures which far outweigh living counterparts is problematic. For comparison, an American bison
The American bison (''Bison bison'') is a species of bison native to North America. Sometimes colloquially referred to as American buffalo or simply Bubalina, buffalo (a different clade of bovine), it is one of two extant species of bison, alongs ...
that they used in their study weighed , and a hippo . Using Burness's methods, ''Diprotodon'' is 25% larger than expected.
Paleobiology
Diet
Like modern megaherbivores, most evidently the African elephant, the Pleistocene Australian megafauna likely had a profound effect on the vegetation, limiting the spread of forest cover and woody plants. Carbon isotope analysis suggests ''Diprotodon'' fed on a broad range of foods, and, like kangaroos, was consuming both C3 (well-watered trees, shrubs, and grasses) and C4 (arid grasses) plants. Still, the low seasonal δ13C values (its carbon isotope ratio remained about the same in both winter and summer, so it ate the same proportion of C3 and C4 plants regardless of their seasonal abundance) indicate that ''Diprotodon'' was a selective eater, at least more so than the modern wombat. The fossilised gut contents (incompletely digested) of one 53,000 year old individual from Lake Callabonna shows its last meal consisted of young leaves, stalks, and twigs.
The molars of ''Diprotodon'' are a simple bilophodont shape. Kangaroos use their bilophodont teeth to grind low-fibre (not too tough) plants as a browser, as well as grass as a grazer. Kangaroos which predominantly graze have specialised molars to resist the abrasiveness of grass, but such adaptations are not exhibited in ''Diprotodon'', so ''Diprotodon'' may have had a mixed diet similar to a browsing wallaby
A wallaby () is a small or middle-sized macropod native to Australia and New Guinea, with introduced populations in New Zealand, Hawaii, the United Kingdom and other countries. They belong to the same taxonomic family as kangaroos and som ...
. It may have chewed like them too, beginning with a vertical crunch before grinding transversely, as opposed to wombats which only grind transversely. Similar to many large ungulate
Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, ...
s (hoofed mammals), the jaws of ''Diprotodon'' were better suited for crushing rather than grinding, which would have permitted it to process vegetation in bulk.
In 2016, Australian biologists Alana Sharpe and Thomas Rich estimated the maximum possible bite force
Bite force quotient (BFQ) is a numerical value commonly used to represent the bite force of an animal, while also taking factors like the animal's size into account.
The BFQ is calculated as the regression of the quotient
In arithmetic, a ...
of ''Diprotodon'' using finite element analysis. They calculated: at the incisors, and across the molar series. For reference, the American alligator
The American alligator (''Alligator mississippiensis''), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the gen ...
can produce forces upwards of . Though these are likely overestimates, the jaws of ''Diprotodon'' were still exceptionally strong, which would have allowed it to consume a broad range of plants, including tough, fibrous grasses.
Migration and sociality
In 2017, Price and colleagues determined that ''Diprotodon'' made seasonal migrations, probably in search of food or watering holes. Price and colleagues did this by measuring the strontium isotope ratio (87Sr/86Sr) at various points along the ''Diprotodon'' incisor QMF3452 from the Darling Downs, and matching those ratios to the ratios of sites across that region. This individual appears to have been following the Condamine River
The Condamine River, part of the Balonne River, Balonne catchment that is part of the Murray-Darling Basin, drains the northern portion of the Darling Downs, an area of sub-coastal southern Queensland, Australia. The river is approximately 500 k ...
, and, while apparently keeping to the Darling Downs during the three years this tooth had been growing, it would have been making a northwest-southeast round-trip annually. This trek parallels the mammalian mass migrations of modern day East Africa.
''Diprotodon'' is the only identified metatherian
Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...
that seasonally migrated between two places. A few modern marsupials, such as the red kangaroo, have been documented making migrations should the need arise, but it is not a seasonal occurrence. Since ''Diprotodon'' could do it, it is not unlikely that other Pleistocene Australian megafauna did it as well.
''Diprotodon'' apparently moved in large herds. These fossilised herds, most commonly unearthed in southeastern Australia, seem to be either predominantly or entirely female (sometimes in tow with juveniles). Such sexual segregation is normally seen in polygynous species, a common social organisation among modern megaherbivores which features an entirely female herd save for their young and the dominant male; the herd breeds exclusively with this male. Similarly, the skull is adapted to handling much higher stresses than what resulted from bite alone, so ''Diprotodon'' therefore may have subjected its teeth or jaws to more strenuous activities than just chewing, such as battling other ''Diprotodon'' for mates, or fending off predators, using the incisors. Like modern red and grey kangaroos (which also sexually segregate), bachelor herds of ''Diprotodon'' seem to have been less tolerant to drought conditions than female herds on account of their larger size and nutritional requirements.
Gait
The locomotion of an extinct animal can be inferred using fossil trackway
A fossil track or ichnite (Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the yea ...
s, which seldom ever preserve in Australia over the Cenozoic. Only the trackways of humans, kangaroos, vombatids, ''Diprotodon'', and the diprotodontid '' Euowenia'' have been identified. ''Diprotodon'' trackways have been found at Lake Callabonna and the Victorian Volcanic Plain grasslands. The diprotodontid manus (forepaw) print is semicircular, and the pes (hindpaw) is reniform (kidney
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blo ...
-shaped). Owing to proportionally small digits, most of the weight was borne on the carpus
In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...
and tarsus (the bones connecting to respectively the wrist and the ankle). Diprotodontines seem to have had a much more erect gait, an adaptation to long-distance travel similar to elephants, rather than the more sprawling posture of wombats and zygomaturines, though there are no fossil trackways of the latter to verify their reconstructed standing posture.
At Lake Callabonna, the single ''Diprotodon'' responsible for the impressions had an average stride length of , trackway width of , and paw dimensions in length x width. The gleno-acetabular length (the distance between the shoulders and pelvis) could have been about , and assuming a hip height of , the maker of tracks was probably moving at around .
At the volcanic plain, the single ''Diprotodon'' responsible for the impressions had an average stride length of , trackway width of , and pes length of . The gleno-acetabular length may have been about , and assuming a hip height of , the maker of tracks was probably moving at around . Its posture was much more sprawled than that from Callabonna, aligning more with what might be expected of ''Zygomaturus'', so the animal may have been a female carrying a large joey in her pouch, the added weight on the stomach altering the gait. The first trackway went on for in a southeasterly direction towards a palaeo-lake. The animal seems to have hesitated stepping down from the first sand bar on its path, with the right pes making three overlapping prints here while shuffling around. The trackway vanishes for a stretch, and reappears while the animal seemingly is stepping on wet sediment. Another diprotodontid trackway appears away moving southerly, which may have been left by the same individual.
Life history
The marsupialmetabolic rate
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ce ...
is about 30% slower than that of placentals, due to a lower body temperature
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
of . Marsupials also give birth at an earlier point in foetal
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal develo ...
development, relying on lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...
to facilitate most of the joey's development; investing in lactation over pregnancy duration can be advantageous in a highly seasonal and unpredictable climate to minimise maternal nutritional requirements (as pregnancy is much more energetically expensive). Consequently, marsupials cannot support as large a litter size or as fast a generation time
In population biology and demography, generation time is the average time between two consecutive generations in the lineages of a population. In human populations, generation time typically ranges from 22 to 33 years. Historians sometimes use this ...
.
Using the relation between female body size and life history in kangaroos, a ''Diprotodon'' female would have gestated for six to eight weeks, and given birth to a single joey. Given its massive size, ''Diprotodon'' may not have sat down to give birth as smaller marsupials do, possibly standing up instead. Like koalas and wombats, the pouch may have faced backwards, so the joey could crawl down across its mother's abdomen to enter, and then attach itself to a teat until it could see (perhaps 260 days) and thermoregulate. It would have permanently left the pouch after 860 days, and suckled until reaching after four or five years.
In large kangaroos, females usually reach sexual maturity
Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definit ...
and enter oestrus
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous ...
soon after weaning, and males need double the time. A similar pattern could have been exhibited in ''Diprotodon''. Assuming a lifespan of up to 50 years, a female ''Diprotodon'' could have given birth eight times.
Palaeoecology
''Diprotodon'' existed during the Pleistocene, and spread out across the entire Australian continent by the Late Pleistocene, most especially following MIS5 approximately 110,000 years ago. The onset of theQuaternary glaciation
The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma (million years ago) and is ongoing. Although geologists describ ...
and the continuous advance and retreat of glaciers at the poles created fluctuating and extreme climatic swings elsewhere. In Australia, the warmer, wetter interglacials were received by forests and woodlands, and the colder, dryer glacial period
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...
s were more conducive to grasslands and deserts. Nonetheless, the continent progressively became dryer and dryer over time as the Asian monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal osci ...
s became less influential over Australia, with the vast interior turning arid and sandy by 500,000 years ago; the mega-lakes (once prominent especially during interglacials over northwestern Australia) drying up; and the rainforests of eastern Australia gradually retreating. Aridity has hastened over the last 100,000 years, especially after 60,000 years ago with surging El Niño–Southern Oscillation
El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea te ...
.
The continent-wide distribution of ''Diprotodon'' indicates that herds trekked across most any habitat Australia had to offer, much like modern African elephants south of the Sahara. ''Diprotodon'' was a member of a diverse assemblage of megafauna endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
to Pleistocene Australia, such as the thylacine
The thylacine ( , or , also ) (''Thylacinus cynocephalus'') is an extinct carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea. The last known live animal was captured in 1930 in Tasma ...
, modern kangaroos, sthenurines (giant short-faced kangaroos), a diversity of modern and giant koala and wombat species, the tapir
Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a pig, with a short, prehensile nose trunk. Tapirs inhabit jungle and forest regions of South and Central America, with one species inh ...
-like '' Palorchestes'', the giant turtle ''Meiolania
''Meiolania'' ("small roamer") is an extinct genus of meiolaniid stem-turtle native to Australasia from the Middle Miocene to Late Pleistocene and possibly Holocene. It is best known from fossils found on Lord Howe Island, though fossils are know ...
'', and the giant bird ''Genyornis
''Genyornis newtoni'', also known as thunder bird and mihirung paringmal (meaning "giant bird"), is an extinct species of large, flightless bird that lived in Australia during the Pleistocene epoch until around 50,000 years ago. Over two met ...
''. ''Diprotodon'' coexisted with the diprotodontid '' Zygomaturus trilobus'', which appears to have clung to the forests, whereas ''Diprotodon'' foraged the expanding grasslands and woodlands. Other contemporary dipotodontids ('' Hulitherium'', ''Z. nimborensia'', and '' Maokopia'') were insular forms restricted to the forests of New Guinea.
Given its massive size, ''Diprotodon'' would have been a tough adversary for native carnivores. It contended with the largest known marsupial predator, ''Thylacoleo carnifex'', and while ''Diprotodon'' fossils gnawed or bitten by ''T. carnifex'' have been identified, it is unclear if the marsupial predator was powerful enough to take down an animal surpassing . Given that the modern jaguar, at half the size of ''T. carnifex'', can bring down a bull, it is not impossible that ''T. carnifex'' could have killed smaller sized ''Diprotodon''. Similar to recent kangaroos with thylacines or quoll
Quolls (; genus ''Dasyurus'') are carnivorous marsupials native to Australia and New Guinea. They are primarily nocturnal and spend most of the day in a den. Of the six species of quoll, four are found in Australia and two in New Guinea. Anoth ...
s, juvenile ''Diprotodon'' may have been at high risk to ''T. carnifex'' predation, as ''T. carnifex'' and juvenile ''Diprotodon'' fossils have been recovered from the same caves. The largest predators of the continent were now-extinct reptiles, most notably the crocodiles ''Paludirex
''Paludirex'' (meaning "swamp king") is an extinct genus of mekosuchine crocodylians from the Pliocene and Pleistocene of Australia. Remains of this animal have been found in the Riversleigh lagerstätte of northwestern Queensland. It was a med ...
'' and ''Quinkana
''Quinkana'' is an extinct genus of mekosuchine crocodylians that lived in Australia from about 28 million to about 10,000 years ago. Most attributed specimens have been found in Queensland. It is speculated to have been one of the top predator ...
'', and the giant lizard megalania (''Varanus priscus''). At in length, megalania was the largest carnivore of Pleistocene Australia.
Extinction
As part of theQuaternary extinction event
The Quaternary period (from 2.588 ± 0.005 million years ago to the present) has seen the extinctions of numerous predominantly megafaunal species, which have resulted in a collapse in faunal density and diversity and the extinction of key ecolog ...
, ''Diprotodon'' and every other land animal heavier than went extinct from Australia. The timing, and thus the exact cause, are unclear because in general there is poor resolution on the ages of Australian fossil sites. Since their discovery, the Australian megafauna have been thought to have died out as the climate worsened, or because of overhunting by the first Aboriginal Australian
Aboriginal Australians are the various Indigenous peoples of the Australian mainland and many of its islands, such as Tasmania, Fraser Island, Hinchinbrook Island, the Tiwi Islands, and Groote Eylandt, but excluding the Torres Strait Isl ...
s. In 2001, Australian palaeontologist Richard Roberts and colleagues dated 28 major fossil sites across the continent, and were able to provide a precise date for megafaunal extinction. They found that most disappear from the fossil record by 80,000 years ago, but ''Diprotodon'' (in addition to the giant wombat '' Phascolonus'', ''Thylacoleo'', and the short-faced kangaroos '' Procoptodon'', '' Protemnodon'', and '' Simosthenurus'') was identified at Ned's Gully, Queensland, and Kudjal Yolgah Cave, Western Australia, which they dated to respectively 47 and 46 thousand years ago. Thus, the megafauna all died out probably between about 41 to 50 thousand years ago. There also seems to have been a rather diverse assemblage of megafauna just before their extinction, and all populations across the continent (or at least in western and eastern Australia) died out at about the same time.
As of 2021, there is still no solid evidence of megafauna surviving past approximately 40,000 years ago. Their latest occurrence (including ''Diprotodon'') is recorded at South Walker Creek mine in the northeast, at about 40,100 ± 1,700 years ago.
At the time of Roberts ''et al.'', the earliest evidence of human activity was 56±4 thousand years old, which was rather close to their calculated date, so they hypothesised that human hunting had eradicated the last megafauna within about 10 thousand years of coexistence. Human hunting had earlier also been blamed for the extinction of North American and New Zealand megafauna. Human activity had then been generally regarded as the main driver of Australian megafaunal extinction, especially because the megafauna had survived multiple extreme drought periods during glacial periods, and at the time there did not seem to be any evidence of unusually extreme climate during this window. Given how slowly marsupials reproduce, even limited megafaunal hunting may have severely weakened their population.
In 2005, American geologist Gifford Miller noticed that fire abruptly becomes much more common about 45,000 years ago, which he ascribed to aboriginal fire-stick farmers, who would have regularly started controlled burns to clear highly productive forests and grasslands. He believed this radically altered the vegetational landscape, and promulgated the expanse of the modern day fire-resilient scrub, at the expense of the megafauna. Many subsequent studies have had trouble firmly linking controlled burns and major ecological collapse. The frequency of fire could have also increased as a consequence of megafaunal extinction, as total plant consumption plummeted, leading to faster fuel buildup.
In 2017, the human-occupied Madjedbebe rockshelter by the northern Australian coast was dated to about 65,000 years, which meant that humans and megafauna had coexisted for over 20,000 years, casting strong doubt on the unilateral role of human activity in megafaunal extinction. Further, in the 2010s, several ecological studies were published in support of major drought conditions coinciding with the final megafaunal extinctions. Therefore, their demise may have been the result of a combination of ecological turmoil, human hunting, and human-driven landscape changes.
In culture
Fossil evidence
Despite the role that the first Australian Aborigines are speculated to have had in the extinction of ''Diprotodon'' and other Australian megafauna, there is a dearth of evidence that humans utilised them at all over the 20,000 years of coexistence. There have been no megafaunal fossils suggestive of human butchery or cooking. In 1984, an upper right ''Diprotodon'' incisor (2I) bearing 28 visible cut marks was discovered in Spring Creek in southwestern Victoria by Gail Paton, and formally studied by Ron Vanderwald and Richard Fullager. The incisor was split in half longitudinally, seemingly while the bone was still fresh, but it was glued together before Vanderwald and Fullager could inspect it. Each piece measures in length. The marks are aligned in a straight line, and measure in length, in width, and in depth. They determined it was inconsistent with bite marks from scavenging ''Thylacoleo'' or mice, and concluded it was incised by humans with flint as a counting system or a random doodle. This specimen became one of the most cited pieces of evidence that humans and megafauna directly interacted, until a 2020 re-analysis by Australian palaeoanthropologist Michelle Langley identified the engraver as most likely atiger quoll
The tiger quoll (''Dasyurus maculatus''), also known as the spotted-tail quoll, the spotted quoll, the spotted-tail dasyure, native cat or the tiger cat, is a carnivorous marsupial of the quoll genus '' Dasyurus'' native to Australia. With male ...
.
In 2016, Australian archaeologist Giles Hamm and colleagues unearthed a partial right radius belonging to a young ''Diprotodon'' in the Warratyi rock shelter. Because it lacks carnivore damage and the rock shelter is a pretty steep climb, they believed that humans were responsible for the bone ending up where it did.
Mythology
When the first massive fossils were dug up in Australia, it was not clear what animals they might have represented as there were no serious scientists on the continent, but locals guessed some may represent rhinos or elephants. The colonists, most vocally Reverend John Dunmore Lang, forwarded these fossils as evidence of the Genesis flood narrative. The aborigines also attempted to fit the finds into their own religious ideas, quickly associating ''Diprotodon'' with the bunyip
The bunyip is a creature from the aboriginal mythology of southeastern Australia, said to lurk in swamps, billabongs, creeks, riverbeds, and waterholes.
Name
The origin of the word ''bunyip'' has been traced to the Wemba-Wemba or Wergaia ...
, a large carnivorous lake monster. Many ethnologists and palaeontologists of the time consequently believed the bunyip is a tribal memory of the lumbering giant which probably frequented marshlands (though at the time it was not impossible that the creature and other megafauna were still alive, as the land exploration of the continent was still ongoing.) Scientific investigation into the bunyip was stigmatised after a purported bunyip skull was sensationalised in 1846 (especially when put on display at the Australian Museum
The Australian Museum is a heritage-listed museum at 1 William Street, Sydney central business district, New South Wales, Australia. It is the oldest museum in Australia,Design 5, 2016, p.1 and the fifth oldest natural history museum in the ...
), until Owen the following year recognised it as the skull of a foal, surprised that the burdgeoning Australian scientific community could have erred so egregiously.
In 1892, Canadian geologist Henry Yorke Lyell Brown reported that aborigenes identified ''Diprotodon'' fossils from Lake Eyre
Lake Eyre ( ), officially known as Kati Thanda–Lake Eyre, is an endorheic lake in east-central Far North South Australia, some north of Adelaide. The shallow lake is the depocentre of the vast endorheic Lake Eyre basin, and contains th ...
as those of the Rainbow Serpent
The Rainbow Serpent or Rainbow Snake is a common deity often seen as the creator God, known by numerous names in different Australian Aboriginal languages by the many different Aboriginal peoples. It is a common motif in the art and religion ...
, which he thought was a giant, bottom-dwelling fish. This notion became somewhat popularised after English geologist John Walter Gregory
John Walter Gregory, , (27 January 1864 – 2 June 1932) was a British geologist and explorer, known principally for his work on glacial geology and on the geography and geology of Australia and East Africa.
The Gregory Rift in the Great Rift ...
(who believed the god was a horned and scaly creature) conjectured that it was a chimaera of ''Diprotodon'' (which he believed had a horn) and a crocodile. Later workers continued to report some link between the Rainbow Serpent and either ''Diprotodon'' or crocodiles.
These kinds of suppositions are not testable, and also require stories to survive oral tradition
Oral tradition, or oral lore, is a form of human communication wherein knowledge, art, ideas and cultural material is received, preserved, and transmitted orally from one generation to another. Vansina, Jan: ''Oral Tradition as History'' (1985) ...
for tens of thousands of years. If Pleistocene megafauna are indeed the basis for some aboriginal mythology, it is unclear if the stories were based on the creatures when they were alive, or their fossils discovered long after they had died out.
Rock art
Australian Aborigines decorated caves with paintings and drawings of several creatures, but the identities of the subjects are oftentimes unclear. In 1907, Australian anthropologist Herbert Basedow found footprint petroglyphs in Yunta Springs and Wilkindinna, which he believed represented those of ''Diprotodon''. In 1988, Australian historian Percy Trezise presented what he thought was a Quinkan depiction of ''Diprotodon'' to the First Congress of the Australian Rock Art Research Association. Both of these claims have their faults as the supposed depictions bear several features inconsistent with what is known about ''Diprotodon''. Furthermore, unlike the more naturalistic artwork of Early European modern humans (which are more easily identifiable as various animals), aboriginal artwork is much more stylistic and is by-and-large uninterpretable by an outsider. The subjects of aboriginal paintings can also be mythological beings fromthe Dreaming
The Dreaming, also referred to as Dreamtime, is a term devised by early anthropologists to refer to a religio-cultural worldview attributed to Australian Aboriginal beliefs. It was originally used by Francis Gillen, quickly adopted by his co ...
rather than a corporeal subject.
See also
*Australian megafauna
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 ...
Notes
References
External links
* *Further reading
* * * * {{Authority control Prehistoric vombatiforms Pleistocene marsupials Pleistocene mammals of Australia Prehistoric marsupial genera Fossil taxa described in 1838 Taxa named by Richard Owen Prehistoric monotypic mammal genera