Bock, Walter J. Department of Biological Sciences, Columbia University, New York, New York.
- Additional Readings
The subclass of birds (Aves) containing all of the known fossil and living birds other than those placed in the extinct Sauriurae (Archaeornithes and Enantiornithes). Comprising more than 30 orders, both fossil and living, members of the Neornithes are characterized by the nature of fusion of the bony elements making up the tarsometatarsus (the fused ankle and foot bones) and the way in which the three bones of the pectoral girdle meet and form the articulation with the humerus. The Neornithes and Enantiornithes share a number of features: a bony, keeled sternum with fully developed powers of flight (secondarily lost in a number of flightless groups); a short tail with the caudal vertebrae fused into a single platelike pygostyle to which the tail feathers attach; a large fused pelvic girdle with a reversed pubis that is fused with a large synsacrum; and large brain and eyes within a fused braincase. The jaws are specialized into a beak covered with a horny rhamphotheca; the upper jaw is kinetic, being either prokinetic or rhynchokinetic. (Prokinesis refers to a bending zone at the base of the upper jaw, and rhynchokinesis to one within the upper jaw.) A few fossil forms possess teeth, but most fossil and all Recent birds have lost the teeth. See also: Aves; Enantiornithes
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information