Adelobasileus cromptoni
| Adelobasileus cromptoni | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||
| Upper Triassic | ||||||||||
| 225 million years | ||||||||||
| Locations | ||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Adelobasileus cromptoni | ||||||||||
| Lucas & Hunt , 1990 | ||||||||||
Adelobasileus cromptoni is an extinct animal species, which isdiscussedas the oldest known mammal , or mammalian animal ( Mammaliaformes ).
So far, only a 1.5 centimeter long, damaged fragment of the back of the head of this species is known. The age of the fossil found in the US state of Texas is dated to around 225 million years and is thus 10 million years older than the previously known fossils of mammalian species. Details of the scaly bone (squamosum) and the promontory reveal a transition stage between the cynodontia, which still belong to the therapsids ("mammal-like reptiles"), and the mammals. However, there are no jaw or tooth fossils that could allow closer conclusions to be drawn about the taxonomic status of the species.
The question of whether Adelobasileus cromptoni is actually a mammal will therefore only be clarified with the discovery of further fossils of this animal.
The level of knowledge on this fragment of the occiput is therefore far removed from the problems that are discussed in the classification of the somewhat younger Sinoconodon , which has been documented by several finds .
literature
- TS Kemp: The Origin & Evolution of Mammals. Oxford University Press, 2005 ISBN 0-19-850761-5