"Therapod" was a class of predatory reptilians. Tiss'shar were regarded as therapods.
The word "theropod" means "beast foot," and was coined by paleontologist Othniel Charles Marsh in 1881 to describe the group of dinosaurs consisting of bipedal carnivores (although later studies have found omnivorous and herbivorous members of the group). Such famous genera as Tyrannosaurus, Allosaurus, and Velociraptor were theropods.
Though spelled with an "o" in real life, the Ultimate Alien Anthology spells "therapod" with an "a."
- Ultimate Alien Anthology