THYLACOSMILUS

extinct genus of carnivorous marsupials found as fossils in Pliocene deposits in South America (the Pliocene epoch began 5.3 million years ago and ended 1.6 million years ago). Thylacosmilus was as large as a jaguar, and the short skull supported a pair of very long and powerfully developed canine teeth that fit into a well-developed flange in the chin region of the lower jaw and were used for stabbing prey. Thylacosmilus became extinct when the land connection between North and South America was reestablished, providing a bridge for the more advanced large North American carnivores, with which Thylacosmilus could not compete. To a remarkable degree, Thylacosmilus paralleled the evolution of the sabretoothed tigers.