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The evolution of birds began in the Jurassic Period, with the earliest birds derived from a clade of theropod dinosaurs named Paraves. [1] Birds are categorized as a biological class, Aves. For more than a century, the small theropod dinosaur Archaeopteryx lithographica from the Late Jurassic period was considered to have been the earliest bird.
A turning point came in the early twentieth century with the writings of Gerhard Heilmann of Denmark.An artist by trade, Heilmann had a scholarly interest in birds and from 1913 to 1916, expanding on earlier work by Othenio Abel, [12] published the results of his research in several parts, dealing with the anatomy, embryology, behavior, paleontology, and evolution of birds. [13]
Adding to this conundrum are fossilized footprints of bird-like tracks that are 210 million years old—a good 60 million years before the arrival of the genus Archaeopteryx, one of the oldest ...
Other mesozoic birds like the toothed, but otherwise modern, birds like Hesperornis were included under the latter in their own superorder, the Odontognathae. [3] According to Romer, the Archaeornithes are characterised by having clawed wings, a reptilian style ribcage without a large carina and the presence of a long, bony tail. [4]
He received a PhD in 1969 from Columbia University (Functional Morphology of Locomotion in Birds). [2] His research interests include: theory and methods of comparative biology, evolutionary theory, biological diversification, systematics, the evolution of morphological systems, historical biogeography, molecular systematics and evolution. [1]
As the bird stem group evolved, distinctive bird features such as feathers and hollow bones appeared. Finally, at the base of the crown group, all traits common to extant birds were present. Under the widely used total-group perspective, [ 17 ] the Crocodylomorpha would become synonymous with the Crocodilia, and the Avemetatarsalia would become ...
Paleornithology, also known as avian paleontology, is the scientific study of bird evolution and fossil birds. It is a hybrid of ornithology and paleontology. Paleornithology began with the discovery of Archaeopteryx. The reptilian relationship of birds and their ancestors, the theropod dinosaurs, are important aspects of paleornithological ...
The classification appears to be an early example of cladistic classification [clarification needed] because it codifies many intermediate levels of taxa: the "trunk" of the family tree is the class Aves, which branches into subclasses, which branch into infraclasses, and then "parvclasses", superorders, orders, suborders, infraorders, "parvorders", superfamilies, families, subfamilies, tribes ...