Neornithes
Neornithes are the most recent common ancestor of all living birds and all their descendants. There are about 9,000 to 10,000 known living species in the world.
Taxonomy
Modern birds are divided into two superorders; the Palaeognathae (tinamous and flightless ratites), and the Neognathae, containing all other birds.
It is generally agreed that the Neornithes evolved in the Cretaceous and that the split between the Palaeognathae and Neognathae, and then the split between fowl and the other Neognathae, occurred before the K/T extinction event. The earliest fossil remains of the Neornithes might be about ten million years after the start of the Cretaceous. Gallornis may be the first fossil, but its remains are only a worn partial femur and a fragment of the humerus.[1]
There are different opinions about whether the radiation of the remaining neognathes occurred before or after the extinction of the other dinosaurs.[2] Molecular dating suggests a Cretaceous radiation, while fossil evidence suggest an early Tertiary radiation. Attempts made to bring together the molecular and fossil evidence have proved controversial.[2]
The classification of modern birds is difficult. Sibley & Ahlquist's Phylogeny and classification of birds (1990) is a landmark work on the classification of birds, though it is often debated and revised. Most evidence suggests that the modern bird orders are accurate taxa.[3] More recently, new fossil and molecular evidence is providing an increasingly clear picture of the evolution of modern bird orders.[4]
Neornithes Media
Archaeopteryx lithographica is often considered the oldest known true bird.
Simplified phylogenetic tree showing the relationship between modern birds and other dinosaurs
Confuciusornis sanctus, a Cretaceous bird from China that lived 125 million years ago, is the oldest known bird to have a beak.
Ichthyornis, which lived 93 million years ago, was the first known prehistoric bird relative preserved with teeth.
Struthio camelus - Etosha 2014 (1) white background
Rhea americana
Little spotted kiwi, Apteryx owenii, Auckland War Memorial Museum white background
NothuraDarwiniiSmit white background
Emu (Dromaius novaehollandiae)
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References
- ↑ Hope, Sylvia 2002. The Mesozoic radiation of Neornithes. In Chiappe, Luis M. & Witmer, Lawrence M. (eds) Mesozoic birds: above the heads of dinosaurs. pp. 339–388 ISBN 0-520-20094-2
- ↑ 2.0 2.1 Ericson P.G.P.; et al. (22 December 2006). "Diversification of Neoaves: integration of molecular sequence data and fossils". Biol Lett. 2 (4): 543–547. doi:10.1098/rsbl.2006.0523. PMC 1834003. PMID 17148284.
- ↑ Romer A.S. & Parsons T. S. 1985. The vertebrate body. 6th ed, Saunders, Philadelphia.
- ↑ McDowell, Sam (1948). "The bony palate of birds" (PDF). The Auk. 65 (4): 520–549. doi:10.2307/4080603. JSTOR 4080603. Archived from the original (PDF) on 2011-07-20. Retrieved 2011-11-08.