Synapsid

Eduzendium article

Synapsida, mammal-like reptiles, are believed to have led to the evolution of mammals. Synapsida rose to power during the Late Carboniferous (Pennsylvanian) period and continued to be the predominant land vertebrate through the Permian and Triassic periods. Prior to the development of the synapsid type skull, reptiles had a low, flat head with jaw muscles that were arranged in such a way to allow their jaws to snap together, but not to bite together in a hard pressing motion. Thus their diets and actions were very limited. With the development of the synapsid skull many other environmental niches were opened up, drastically changing the way that the environment lived and evolved, such as plants which required the evolution of better defensive characteristics.

Pelycosauria

Pelycosauria was the earliest and most primitive of the synapsida reptiles, and thought to have roamed the earth as early as 300 million years ago during the Late Carboniferous.

Dentition

The mammal-like reptiles developed the heterodont shaped dentition with sharp edged incisors for cutting, pointed canines for tearing, and cheek teeth with flat crushing surfaces for chewing. Though they still retained the typical reptilian characteristic of replacing old and worn teeth with new teeth, as the synapsids evolved they gained the ability to keep their teeth longer. Because they were able to keep their teeth longer they were capable of developing more specialized dentition and a better precision bite. This allowed for their food to be chewed down to a pulp, easier to swallow, and thus better to digest. This, in turn, allowed for the nutrients from the food to be released and used by the body much more quickly.

Insulation

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