therapsid

noun

the·​rap·​sid thə-ˈrap-səd 

: any of an order (Therapsida) of advanced synapsid vertebrates that flourished during the Permian and Triassic periods with the last forms becoming extinct during the Cretaceous period and that are considered ancestors of the mammals

therapsid adjective

Examples of therapsid in a Sentence

Recent Examples on the Web

But there’s still much to learn about this terrifying therapsid, and its life before the largest extinction event in the history of the planet. —Sara Kiley Watson, Popular Science, 14 Sep. 2023

Scientists have classified the four-legged predators as therapsids, along with the creatures that evolved into modern-day mammals. —Matt Hrodey, Discover Magazine, 24 May 2023

Word History

Etymology

New Latin Therapsida, from ther- mammal (from Greek thēr wild animal) + apsid-, apsis arch, vault — more at fierce, apsis

First Known Use

1912, in the meaning defined above