Patagopteryx
| Patagopteryx | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Patagopteryx , skeletal reconstruction |
||||||||||||
| Temporal occurrence | ||||||||||||
| Santonium (Upper Cretaceous) | ||||||||||||
| 86.3 to 83.6 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the order | ||||||||||||
| Patagopterygiformes | ||||||||||||
| Alvarenga & Bonaparte , 1992 | ||||||||||||
| Scientific name of the family | ||||||||||||
| Patagopterygidae | ||||||||||||
| Alvarenga & Bonaparte, 1992 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Patagopteryx | ||||||||||||
| Alvarenga & Bonaparte, 1992 | ||||||||||||
| Art | ||||||||||||
|
||||||||||||
Patagopteryx is an extinct genus of flightless birds from the Upper Cretaceous Period . The fossil remains of a total of three specimens were found in the Bajo de la Carpa Formation in northwestern Patagonia ( Neuquén ). The only species is Patagopteryx deferrariisi .
features
Patagopteryx was about the size of a chicken, with strong hind legs and receding wings. The foot is pamprodactyl , all four toes point forward. The phalangeal formula is 2-3-4-5.
The skeleton suggests that its ancestors were able to fly. The sternum is small and has no sternum crest ( Carina sterni ). The carpometacarpus, a bone that arose from the fusion of the distal carpal bones ( ossa carpalia distalia ) with one another and with the proximal ends of the originally three metacarpal bones ( ossa metacarpalia ), is also small. Patagopteryx is the oldest bird for which a secondary inability to fly can be proven.
Its trunk vertebrae were of the primitive procoelen (front concave, rear convex) type, all other vertebrae were heterocoel (both ends concave), as is typical of modern birds. The ischium and pubis both point backwards. The elongated bones of the species show clear growth rings, which is also typical for the enantiornithes , but does not occur in any other Cretaceous or modern bird group. Perhaps it was physiologically different from modern birds, was not completely endothermic, and had to spend part of the year in a kind of cold rigor. He lived in a continental climate , which was characterized by large temperature fluctuations due to the season.
Systematics
Patagopteryx was originally thought to be a primitive member of the ratites . Today his position within the bird system is considered isolated and he is in his own family and order. The probable systematic position shows the following cladogram :
| Birds (aves) |
|
||||||||||||||||||||||||||||||||||||||||||
|
|
literature
- Alan Feduccia : The Origin and Evolution of the Birds. 2nd ed. Yale University Press, New Haven, Conn. 1999, ISBN 0-300-07861-7 .
- Luis M. Chiappe, Lawrence M. Witmer (Eds.): Mesozoic birds. Above the heads of dinosaurs . University Press, Berkeley, Calif. 2002, ISBN 0-520-20094-2 , limited preview in Google Book Search.
- Michael Benton : vertebrate paleontology ( Vertebrate Paleontology , 1991). Pfeil Verlag, Munich 2007, ISBN 978-3-89937-072-0 .