page_title: Diprotodon
section_title: Taxonomy
hierarchical_section_title: Diprotodon / Taxonomy
caption_attribution_description: English: Dorsal view (A) and lateral view including the mandible (B). Scale bar = 10 cm. Abbreviations: COR, coronoid process; FR, frontal; JUG, jugal; LAC, lacrimal; MAP, masseteric process; MAX, maxillary; MEF, mental foramen; OC, occipital; OCC, occipital condyle; PAR, parietal; MR, masseteric ridge; PMX, premaxillary; SQ, squamosal. Illustration by P Trusler courtesy T Rich, Museum Victoria and the ARC.
context_page_description: Diprotodon, meaning in Greek "two forward teeth", is an extinct genus of diprotodontid marsupial native to Australia during the Pleistocene epoch. The genus is currently considered monotypic, containing only Diprotodon optatum, the largest known marsupial to have ever existed. It is considered one of the core species of the "Australian megafauna", which ranged throughout the continent during the Pleistocene. Diprotodon existed from about 1.6 million years ago until extinction some 44,000 years ago.
  Diprotodon species fossils have been found in sites across mainland Australia, including complete skulls and skeletons, and foot impressions. The largest specimens were hippopotamus-sized: about 3 m from nose to tail, standing 2 m tall at the shoulder and weighing about 2,790 kg. Diprotodonts may have been depicted on Aboriginal rock art images in Quinkan traditional country. Diprotodon became extinct sometime after 44,000 years ago, after the initial settlement of the continent, the role of human and climactic factors in its extinction are uncertain and contested.
context_section_description: Diprotodon was named by Owen (1838). It was assigned to the Diprotodontidae by McKenna and Bell (1997). The historical classification of Diprotodon consisted of eight species (D. optatum Owen, 1838; D. australis Owen, 1844; D. annextans McCoy, 1861; D. minor Huxley, 1862; D. longiceps McCoy 1865; D. loderi Krefft, 1873a; D. bennettii Krefft, 1873b (nec D. bennettii Owen, 1877); and D. bennettii Owen, 1877 (nec D. bennettii Krefft, 1873b); based on size or slight morphological differences of single specimens collected from isolated geographic regions. Bimodal dental sizes, rather than a continuum of tooth sizes, and identical male and female dental morphology, indicate sexual dimorphism instead of separate species, thus providing strong evidence that the eight species are synonyms for D. optatum. Diprotodon is ultimately thought to have evolved from Euryzygoma dunensis, a smaller diprotodontid known from the Pliocene of eastern Australia, and a smaller form of Diprotodon, labelled D. ?optatum, intermediate in size between the two taxa, is known from the Early Pleistocene (1.77–0.78 Ma) in Nelson Bay near Portland, Victoria
caption: Drawing of the skull of Diprotodon
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