Steropodon
| Steropodon | ||||||||||||
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Steropodon |
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| Temporal occurrence | ||||||||||||
| Lower Cretaceous | ||||||||||||
| 105 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Steropodon | ||||||||||||
| Archer , Flannery , Ritchie & Molnar , 1985 | ||||||||||||
Steropodon galmani is an extinct species of mammal . She lived in the Cretaceous period in Australia and one of the earliest known ancestor of the platypus .
features
The fossil finds are limited to parts of the lower jaw and several molars , which were discovered in opalized form in New South Wales . The molars were around 5 to 7 millimeters long and 3 to 4 millimeters wide. The three cusps of the molars, which are reminiscent of the tribosphenic teeth of some higher mammals, are remarkable . Otherwise, little is known about steropodon . Based on the length of the jaw parts found, the body length is estimated to be around 40 to 50 centimeters. While this would be smaller than the Kollicodon living in the same region , it would still be very large for Mesozoic mammals.
Systematics
Steropodon is placed together with Teinolophos in the Steropodontidae, these are the earliest known relatives of the Ornithorhynchidae , which are still represented today by the platypus . The similarities of the teeth of these and related species with those of other Mesozoic mammals from Gondwana has sparked a new discussion about the ancestral relationships of the mammals to the other mammal groups. See also systematics of the primary mammals .
literature
- TF Flannery , M. Archer , A. Ritchie, RE Molnar: First Mesozoic mammal from Australia - an early Cretaceous monotreme. In: Nature . 318, 1985, pp. 363-366.
- TS Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford et al. 2005, ISBN 0-19-850761-5 .
