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A = Anapsid, B = Synapsid, C = Diapsid. It was traditionally assumed that first reptiles were anapsids, having a solid skull with holes only for the nose, eyes, spinal cord, etc.; [10] the discoveries of synapsid-like openings in the skull roof of the skulls of several members of Parareptilia, including lanthanosuchoids, millerettids, bolosaurids, some nycteroleterids, some procolophonoids and ...
Slight increase in diversity of cold-tolerant ostracods and foraminifers, along with major extinctions of gastropods, reptiles, amphibians, and multituberculate mammals. Many modern mammal groups begin to appear: first glyptodonts, ground sloths, canids, peccaries, and the first eagles and hawks. Diversity in toothed and baleen whales. 33 Ma
Figure 1:In mammals, the quadrate and articular bones are small and part of the middle ear; the lower jaw consists only of dentary bone.. While living mammal species can be identified by the presence of milk-producing mammary glands in the females, other features are required when classifying fossils, because mammary glands and other soft-tissue features are not visible in fossils.
Sauropsida (Greek for "lizard faces") is a clade of amniotes, broadly equivalent to the class Reptilia, though typically used in a broader sense to also include extinct stem-group relatives of modern reptiles and birds (which, as theropod dinosaurs, are nested within reptiles as more closely related to crocodilians than to lizards or turtles). [2]
It is a precursor of later amniotes (including both the reptiles and the ancestors of mammals). Alpha keratin first evolves here; it is used in the claws of modern amniotes, and hair in mammals, indicating claws and a different type of scales evolved in amniotes (complete loss of gills as well).
Non-crocodilian reptiles have 3-chambered hearts, which are less efficient because they let the two flows mix and thus send some de-oxygenated blood out to the body instead of to the lungs. Modern crocodilians' hearts are 4-chambered, but are smaller relative to body size and run at lower pressure than those of modern birds and mammals.
“For Ruby Reynolds, not only did she find this important fossil but also helped to name a type of gigantic prehistoric reptile,” Lomax said in an email. “There are probably not many 15-year ...
Synapsida [a] is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant reptiles and birds).