Abelisaurus comahuensis is a theropod, and the first example of the Abelisauridae family. It is theorized to have been a bipedal carnivore with slender legs and tiny arms (even smaller than tyrannosaur arms).
Abelisaurus lived in the Late Cretaceous plains of South America, in the area that is now the province of Río Negro in Argentina. As they were separated at the time, it is believed that abelisaurs evolved in South America around the same time as tyrannosaurs in North America.
The holotype is only a partial skull, which was discovered in the Lago Pellegrini stone quarries of the Río Negro province of Argentina in 1983 by Roberto Abel. No paratypes have been found, so all estimates of Abelisaurus' size and anatomy are extrapolations based on other, more complete abelisaurs.
The name "Abelisaurus" is to honour Professor Roberto Abel, the former director of the Museum of Cipolletti in Argentina; Roberto discovered the holotype of Abelisaurus comahuensis, which is now stored in the Museum of Cipolletti. "Comahuensis" refers to the region in Argentina where the holotype was discovered, Comahue, which spans three provinces: Neuquén, Río Negro, and the Northern part of Patagonia.