Temporal range: Lower Paleocene – Upper Miocene
|An artist's illustration of Obdurodon tharalkooschild|
Obdurodon is a large platypus, and, unlike other monotremes, might've been able to eat plants, due to it having molars. They were also extremely large, similar to the giant echidnas Zaglossus hacketti and Zaglossus robustus.
Obdurodon dicksoniDiscovered in 1984 by Michael Archer, F. A. Jenkins, S. J. Hand, P. Murray, and H. Godthelp, at Riversleigh in North West Queensland.
Habitat : Queensland Epoch : Lower and middle Miocene This species is characterized by a skull and several scattered teeth. Physically, it would have looked much like a modern platypus, although significant differences are few . The holotype is kept at the Queensland Museum in Brisbane. Obdurodon dicksoni grew profoundly larger than the modern platypus. The septomaxilla (a part of the upper jawbone) of O. dicksoni is bigger than for the platypus, which supposes a hypertrophied beak. The coronoid and angulary processes of O. dicksoni have quite disappeared in the platypus, leaving the platypus's skull flat on the sides. This indicates the mastication technique of O. dicksoni was different from that of the platypus, using the muscles anchored to these processes. O. dicksoni's beak has an oval hole surrounded by bones in the center, whereas the platypus' beak has a V-shape and no longer surrounded by bones. O. dicksoni' retained molar teeth into adulthood, whereas in the modern platypus, the adults only have keratinized pads (juveniles lose their molar teeth upon adulthood). The shape of its beak suggests O. dicksoni sought prey by digging in the sides of rivers, whereas the modern platypus digs in the bottom of the river. O. dicksoni' has (like the platypus) shearing crests instead of incisor and canine teeth. It bore two premolars and three molars on each side of the lower jaw. The M1 had six roots, the M2 had five, and the M3 only one. The upper jaw bore two premolars and two molars on each side. The M1 had six roots, the M2 four. The premolars had only one root and a very different shape from the molars. They were separated from the shearing crests by an area without dentition. The roots of the molars were barely a third as high as the crown. Molars had only been found apart from skulls, implying that they were not well-anchored.
Discovered in 1975 by Mike O. Woodburne and Dick H. Tedford at Etudunna Formation in the desert of Tirari. Habitat : South Australia Epoch : Upper Oligocene The holotype is an inferior left molar and is kept in the South Australia's Museum, Adelaide. The tooth has six roots. There also have been found M2 with four roots and fragments of jawbone and pelvis. Obdurodon insignis had one more canine tooth (NC1) than its ancestor Steropodon galmani. Its beak must have been proportionally smaller than the one of Obdurodon dicksoni.