Unformatted text preview: ectothermy) as the obsolete term "mammal-like reptiles" implied. The amniotes that had appeared during the late Carboniferous diversified from the protothyrid stock along two lineages: one leading to the quadrupedal pelycosaurs (stem synapsids) of the Carboniferous-Permian and then to the therapsids (advanced synapsids) of the Permian-Triassic; and the other leading to the bipedal thecodonts of the Permian-Triassic. Dimetrodon, shown above, was a member of the pelycosaurs, or non-mammalian therapsids. By the end of the Permian the therapsids had developed, a group possibly characterized by some degree of endothermy (warm-bloodedness). The early mammals of the Triassic period are possibly an offshoot or descendant group of the therapsids....
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- Fall '10
- Biology, Synapsid, Synapsids, mammal-like reptiles, Non-mammalian Synapsids, quadrupedal pelycosaurs