What is the Difference Between Diapsid and Synapsid?

Diapsids and synapsids are two different amniotic clades, which are groups of vertebrates that lay their eggs on land. The main differences between diapsids and synapsids are the structure of their skulls and the number of temporal fenestrae, post-orbital openings in the skull that allow muscles to expand and lengthen.

Diapsids have two temporal fenestrae behind each eye, while synapsids have only one temporal fenestra behind each eye. The diapsids include mostly extinct animals and some modern groups, such as lizards, snakes, and crocodiles. The synapsids evolved through the therapsids and mammals, with present-day synapsids including all mammals like humans, blue whales, and monotremes.

In terms of teeth, diapsids typically have only canines, while synapsids have more types of teeth, including incisors, canines, and molars. Synapsids can be further subdivided into two groups, the therapsids (mammal-like reptiles from which mammals evolved) and the mammals. Diapsids include the sauropsids (reptiles and birds) and the archosaurs (ancestors of birds, crocodiles, and other extinct groups).

In summary, diapsids have two temporal fenestrae and usually have canine teeth, while synapsids have only one temporal fenestra and a more diverse set of teeth, including incisors, canines, and molars.

Comparative Table: Diapsid vs Synapsid

Here is a table comparing the differences between diapsids and synapsids based on the given information:

Diapsids have two temporal fenestrate behind each eye, while synapsids have only one. Diapsids include reptiles and birds, whereas synapsids include mammals and mammal-like animals.