Ornithothoraces

Ornithothoraces
Black- browed albatross ( Thalassarche melanophris )
Temporal occurrence
Lower Cretaceous to this day
130 to 0 million years
Systematics
Row : Land vertebrates (Tetrapoda) without rank: Amniotes (Amniota) without rank: Sauropsiden (Sauropsida) Class : Birds (avialae) without rank: Pygostylia without rank: Ornithothoraces
Scientific name
Ornithothoraces
Sereno , 1998

As a subgroup of birds , the Ornithothoraces comprise the extinct Cretaceous group of the Enantiornithes and the Ornithuromorpha , to which all representatives of modern birds belong in addition to a multitude of exclusively Mesozoic forms .

Compared to primeval birds such as Archeopteryx , Jeholornis , Sapeornis and the Confucius ornithids , the Ornithothoraces have a number of common derived features : a thumb wing is present and attaches to a shortened first finger; the claw of the 3rd finger is completely reduced, as is the 5th metatarsal ; on the tibiotarsus the joint heads are undercut by a narrow and deep furrow ; the ventral cusp of the humerus protrudes towards the tail and is delimited from the shoulder joint head by a deep notch; the rear end of the shoulder blade tapers to a point; the shoulder blade starts far below the end of the raven bone near the shoulder ; the shoulder joint bases of the shoulder blade and raven bone lie at an acute angle to each other (and not in one plane); the front edge of the sternum is broad and parabolic; the number of thoracic vertebrae is twelve or less.

The morphological innovations in the shoulder girdle and in the forelimbs of the Ornithothoraces are related to an improved ability to fly. The theory that the Enantiornithes developed these traits independently from the relatives of Modern Birds and are actually more closely related to Archeopteryx is currently rejected by most paleornithologists in favor of the validity of the Ornithothoraces group .

Both the enantiornithes and the ornithuromorpha are documented for the first time since the Lower Cretaceous - especially numerous from the northeast Chinese Jehol group .

Systematics

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)	Pygostylia    Confuciusornithidae      ? Oviraptorosaur (not to birds according to Fastovsky and Weishampel 2005)   Ornithothoraces    Enantiornithes   Ornithuromorpha   Patagopteryx      Vorona   Ornithurae    Hesperornithiformes   Carinatae   Ichthyornithiformes      Neornithes ("Aves" after Fastovsky and Weishampel 2005)      Archeopterygidae      Rahonavis      Jeholornis

Individual evidence

1. ↑ Chiappe, LM (2002): Basal bird phylogeny: problems and solutions. In: LM Chiappe and LM Witmer (Eds.): Mesozoic Birds: Above the Heads of Dinosaurs. 448-472. University of California Press, Berkeley.
2. ^ A. Feduccia (1996): The origin and evolution of birds. Yale University Press, New Haven / London. ISBN 0-300-06460-8
3. ^ Zhou, Z. & Zhang, F. (2007): Mesozoic birds of china - A synoptic review. Frontiers of Biology in China, 2 (1), 1-14. doi: 10.1007 / s11515-007-0001-y
4. ↑ Michael J. Benton: Vertebrate Palaeontology. 3. Edition. Blackwell, Malden 2005, ISBN 0-632-05637-1 .
5. ↑ ^{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 .
6. ↑ Zhonghe Zhou: The origin and early evolution of birds: discoveries, disputes and perspectives from fossil evidence. In: Natural Sciences. 91, No. 10, 2004, pp. 455-471, doi : 10.1007 / s00114-004-0570-4 .