synapsid

1. Any of various amniotes with one temporal opening on each side of the skull. Synapsids emerged in the late Permian Period and were characterized by carrying their limbs under their body and developing front teeth that were different from their back teeth. One group of synapsids, the therapsids, gave rise to the mammals.

2. Compare anapsid diapsid therapsid

Example Sentences

The area's rust-colored rocks date back to the early Permian period more than 270 million years ago and contain the fossilized remains of ancient reptiles, amphibians and sail-backed synapsids, the precursors to modern mammals.

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They found a major shift in synapsid jaw function roughly 270 million years ago linked to a significant shift in predatory behaviour that has important implications for the evolution of our earliest ancestors.

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Hellert created a massive family tree of the synapsids, the group of animals of which mammals are the last surviving members.

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These synapsids, he added, “are more closely related to us than any dinosaur or other reptile.”

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The researchers set about amassing a data set of 56 fossil synapsids, the group that contains mammals and their relatives, to pinpoint when mammal ancestors crossed this critical physiological threshold.

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