Orthogoniosaurus

Orthogoniosaurus (meaning "straight angled lizard", referring to the straight posterior edge of its type tooth) is a dubious genus of theropod dinosaur from the late Maastrichtian-age Upper Cretaceous Lameta Formation of Jabalpur, India. It is based on one small, fragmentary tooth (preserved section 27 mm (1.1 in) long).

Because it is the earliest published name for a Lameta theropod, it has sometimes been used as a synonym for other contemporaneous theropods, such as Indosaurus and Indosuchus. As a tooth taxon, however, such usage has been discouraged. Ralph Molnar in 1990 noted that the form of the tooth was most like teeth from the rear of theropod jaws, although the lack of serrations on the leading edge was unusual. In 2004 it was considered to be a dubious ceratosaurian. Later studies have considered it to be a abelisaurid.

"Massospondylus rawesi", another tooth taxon, is sometimes given as a second species. It was suggested that the tooth may not be dinosaurian, and could be substantially older. However more recent research agrees on a cretaceous age and likely pertain to a theropod, possibly an abelisaurid.