Platypus Evolution

Obdurodon dicksoni Eon Era PeriodEpoch Age (millions of ) The most complete fossilised skull of a Holocene 0.0117 from the Riversleigh World Heritage Area was described in 1992 7 Pleistocene (15-10 million years old) .

Quaternary 2.58

Pliocene 5.333

Miocene

Neogene The extant platypus Ornithorhynchus anatinus 23.03

Cenozoic insignis 33.9 In 1971, two fossil teeth from Obdurodon insignis were discovered in the Tirari Desert, SA. They were Eocene found to be similar to the teeth Obdurodon tharalkooschild of extant baby A description of a tooth from the 56 6 largest platypus, , Paleogene (25 million years old) . Obdurodon tharalkooschild was published in 2013. The tooth was Phanerozoic sudamericanum discovered in the Riversleigh World Heritage 66 Teeth from Monotrematum sudamericanum Area and dated to the middle were found in southern in 1992. to early Pliocene5. It grew to about 700 mm long (63-61 million years old)3,4. Upper Platypuses Family Ornithorhynichidae 100.5 Steropodon galmani Opalised In 1984, an opalised jaw from Teinolophus trusleri Reconstruction a platypus-like

Mesozoic The smallest, oldest and (Steropodon galmani) was most primitive known member unearthed at Lightning Ridge, Lower of the . Described Illustration NSW. This was still the age of in 1992 from a partial Fossil and the dinosaurs from (110 million years old)2. 1 145 (~123 million years old) .

References 1. Rich et al. (2013). Alcheringa 4(40): 475-501. 5. Pian et al. (2013). J. Vert. Paleo. 33(6): 1255-1259. 2. Archer et al. (1985). 318: 363-366. 6. Woodburne & Tedford (1975). Am. Mus. Nat. Hist. 2588: 1-11. 3. Pascual et al. (1992). Pp. 2-15 In ‘Playtpus and ’ (M.L. Augee ed.). Roy. Zoo. Soc. Aust. 7. Archer et al. (1992). Pp. 15-27. In ‘Playtpus and Echidnas’ (M.L. Augee ed.). Roy. Zoo. Soc. Aust. 4. Pascual et al. (2002). Acta Palaeotol. Pol. 47(3): 487-492.