Pygostylia
Pygostylia | ||||||||||||
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![]() Left: the reptile-like tail of Archeopteryx . |
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Temporal occurrence | ||||||||||||
Lower Cretaceous to this day | ||||||||||||
130 to 0 million years | ||||||||||||
Systematics | ||||||||||||
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Scientific name | ||||||||||||
Pygostylia | ||||||||||||
Chatterjee , 1997 |
The taxon Pygostylia describes a group within the birds (class Aves), which is distinguished from other birds such as Archeopteryx by a shortened bony tail and the fusion of the last caudal vertebrae to a pygostyle . Further features for diagnosing the group are a number of seven or more pelvic vertebrae ( sacralia ), which are fused together in the so-called synsacrum , and elongated raven bones ( coracoid ).
The Pygostylia include all recent bird groups as well as most fossil ones . The affiliation of the oviraptorosaurs is under discussion : In some species the last caudal vertebrae were fused into a pygostyle-like structure. Some paleontologists see this feature as an indication that oviraptorosaurs were flightless descendants of early (airworthy) birds. Others doubt that the "pygostyle" of the oviraptorosaurs is homologous to that of the birds and place this group among the "non-avian dinosaurs " (a term used by cladisticians that means dinosaurs in the traditional sense, i.e. exclusively their descendants, the birds).
Systematics of birds taking into account fossil groups of birds
The systematics of the birds is as follows, including the group Pygostylia and new findings on the relationships among Mesozoic birds:
Aves ("Avialae" after Fastovsky and Weishampel 2005) |
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See also
Individual evidence
- ↑ Michael J. Benton : Vertebrate Palaeontology. 3. Edition. Blackwell, Malden MA 2005, ISBN 0-632-05637-1 .
- ↑ a b c d David E. Fastovsky , David B. Weishampel : The Evolution and Extinction of the Dinosaurs. 2nd Edition. Cambridge University Press, Cambridge 2005, ISBN 0-521-01046-2 .
- ↑ Zhonghe Zhou : The origin and early evolution of birds: discoveries, disputes and perspectives from fossil evidence. In: The natural sciences . Vol. 91, No. 10, 2004, pp. 455-471, doi: 10.1007 / s00114-004-0570-4 .