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Definition
| This derived group of therapsids dominated terrestrial diversity in the late Permian. They were specialized for an herbivorous diet, with jaws consisting of a horny beak which provided a continuous cutting surface. |
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Definition
| This group of diverse animals had a higher metabolic rate than pelycosaurs. It included the dyconodonts which gave rise to the cynodonts, which gave rise to modern mammals. This group had a rigid skull, heterodont teeth, and slender limbs. |
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Definition
| These now extinct mammals probalby occupied a niche similar to living rodents. They were small terrestrial and semiarboreal omnivores with teeth that were specialized for grinding rather than shearing. |
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Definition
| These were synapsids that were common in the late Paleozoic and were mostly carnivores. They had an arched palate and dramatic elongation of the nureal spines. |
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Definition
| These were synapsids that appeared during the late Permian period and were comoon in the Triassic. Body size was dramatically reduced, so that they were shrew size by the late Triassic. They had mulitcusped teeth, a mammal like muzzle, lips whiskers, and respriatory turbinates. |
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Definition
| These therian mamals are most common in Australia. They have an inflected angle to the dentary bone, and they have bones that project forward from the buis. After they are born, offspring in the group often spend time living in a pouch. |
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Definition
| These were the major predators of the late Permain and early Triassic. For more biting power, they were characterized by the development of the coronoid process of the dentary and vertical flange at the back of the jaw for insertion of adductor muscles. |
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Definition
| These living mammals are probably like the earliest mammals in that they lack nipples, have lower metabolic rates (than most mammals), and lack effective sweat glands. They have ribs on the cervical vertebrae, and they have less specialzed ankle joints than therians. |
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Definition
| Most mammals alive today are of this type. They have an auditory bulla. In addition to a choriovitelline placenta, they have a later developing chorioallantoic placenta. young in this group may be born singly or in litters. |
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