Ornithothoraces

Black- ( Thalassarche melanophris )

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

Compared to primitive birds like Archaeopteryx, Jeholornis, Sapeornis and Confuciusornithiden the Ornithothoraces have a number of common characteristics derived: A Daumenfittich exists and is applied to a shortened first finger; the claw of the third finger is completely reduced, as the fifth metatarsal bone; the tibiotarsus the rod ends of a narrow and deep furrow be undercut; the Ventralhöcker of the humerus protrudes upward tail and is separated from the shoulder joint head by a deep notch; the rear end of the shoulder blade is tapered; the scapula is far below the shoulder on the near end of the Raven leg; the shoulder joint socket of the shoulder blade and raven leg at acute angles to each other (and not in a plane ); the front edge of the breastbone is wide and parabolic; the number of thoracic vertebrae is twelve or less.

The morphological changes in the shoulder girdle and the forelimbs of Ornithothoraces associated with an improved ability to fly. The theory that the Enantiornithes these features evolved independently from the relatives of modern birds are related and actually closer to Archaeopteryx, is currently being rejected by most Paläornithologen in favor of the validity of the group Ornithothoraces.

Both the Enantiornithes and the Ornithuromorpha are first occupied since the Lower Cretaceous - especially numerous in northeast China's Jehol Group.

System

The systematics of birds presents itself, including the group Pygostylia and new findings on the family relationships of Mesozoic birds as follows:

Confuciusornithidae

? Oviraptorosaurier (not too loud birds Fastovsky and Weishampel 2005)

Enantiornithes

Patagopteryx

Vorona

Hesperornithiformes

Ichthyornithiformes

Neornithes ( " Aves " by Fastovsky and Weishampel 2005)

Archaeopterygidae

Rahonavis

Jeholornis