Barrett, Paul M. Department of Palaeontology, The Natural History Museum, London, United Kingdom.
- Phylogeny and evolution
- Links to Primary Literature
- Additional Readings
One of two constituent clades of Dinosauria (the other being Saurischia). Ornithischian dinosaurs are characterized by the possession of numerous anatomical features, notably the configuration of the pelvis. In ornithischian hips, the pubis bone (which points downward and forward in the majority of other reptile groups) has rotated posteriorly to lie parallel to the ischium (Fig. 1). This configuration is superficially similar to that seen in living birds, but actually represents an example of evolutionary convergence (birds are, in fact, descended from saurischian dinosaurs). Other features that characterize ornithischians include the presence of ossified tendons that form a complex lattice arrangement supporting the vertebral column, a single midline bone called the predentary that lies at the front end of and connects the two lower jaws, and a palpebral bone that traverses the orbit (Fig. 2).
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 8700 articles 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