Talk:Fossil birds

From Wikipedia, the free encyclopedia

This article is part of WikiProject Extinction, an attempt at creating a standardized, informative, comprehensive and easy-to-use resource on extinct animals, extinct plants and extinction in general. If you would like to participate, you can choose to edit this article, or visit the project page for more information.

The number of fossil taxa in some extant genera (e.g. Phalacrocorax) is overwhelming. I suggest that by and by (pending sufficient references) these are moved into an appropriate category in the genus article (e.g. "Evolution of Cormorants" for the example above). Then only the genera with known fossil species would be listed, shortening the article considerably. Eventually (I'm talking the next years here) it would be desirable to pep up the articles on higher-level Neornithes taxa with a brief section on evolutionary origins, as is already the case in some examples. See Fossil_birds#Sphenisciformes and Penguins for an example of how to layout the prehistoric spp of extant genera and save considerable space. Dysmorodrepanis 04:28, 9 July 2006 (UTC)

[edit] Polyphyly of the Aves

Kurochkin (2006) showed that the Sauriurae is monophyletic, with characters uniting Archaeornithes and Enantiornithes, and that the Ornithurae evolved from a different archosaurian ancestor in the Late Triassic. This suggests that the Aves as phylogenetically reconstructed is polyphyletic; scientists need to rethink the true origins and evolution of birds. This paper also demonstrates that Protoavis is probably the ancestor of the Ornithurae. The abstract of this article is reads:

The hypothesis of the direct origin of birds from theropod dinosaurs has recently become widespread. Direct sisterly relationships between theropods and birds were assumed in the basis of random and formal synapomorphies, such as the number of caudal vertebrae, relative length of the humerus, and flattening of the dorsal margin of the pubis. In essence, this hypothesis is supported by the characters of theropods and birds, such as the presence of feathering, furcula, uncinate processes of ribs, pygostyle, double-condyled dorsal joint of the quadrate, and posteriorly turned pubis, which are recognized as homologies. Until recently, these characters have been regarded as avian apomorphies; however, they are presently known in various coelurosaurian groups. At the same time, they occur in various combinations in the Dromaeosauridae, Troodontidae, Oviraptoridae, Therizinosauridae, and Tyrannosauridae. None of the theropod groups possesses the entire set of these characters. This suggests that theropods and birds acquired them in parallel. Theropod dinosaurs and Sauriurae (Archaeornithes and Enantiornithes) show a number of important system synapomorphies, which indicate that they are closely related. Ornithurine birds lack such synapomorphies; however, their monophyly is supported by a large number of diagnostic characters. The hypothesis of independent origin of Sauriurae and Ornithurae is substantiated; the former are considered to have evolved from theropods in the Jurassic, while the latter deviated from a basal archosauromorph group in the Late Triassic. The hypothesis that birds existed in the Early Mesozoic is supported by the findings of small avian footprints in the Upper Triassic and Lower Jurassic of different continents.

Kurochkin, E. N., 2006, Parallel evolution of theropod dinosaurs and birds: Zoologicheskii Zhurnal, v. 85, n. 3, p. 283-297.

Extraordinary claims require extraordinary evidence. To propose that a complex structure like the feather evolved twice in unrelated reptile groups is quite an extraordinary claim. Protoavis and "avian" footprints are not considered extraordinary evidence by a vast, vast majority of paleontologists.Dinoguy2 12:37, 15 October 2006 (UTC)