Gualicho

Gualicho shinyae is an extinct genus of theropod dinosaur from the Late Cretaceous of Patagonia, Argentina. It was discovered in 2016. Its name comes from the gaulichu, a demon in Argentinian mythology. It was a close relative to the African Deltadromeus. It possessed reduced arms and two-fingered hands, similar to those of Tyrannosaurus rex, showing that carnosaurs were subject to the same convergent evolution of limb-reduction as tyrannosaurs and abelisaurids. It may be synonymous with the megaraptoran Aoniraptor, due to their similar caudal vertebrae and similar location, though this is still unconfirmed.

Discovery[]

On February 13, 2007, Akiko Shinya, preparator of the Field Museum of Natural History, east of the Ezequiel Ramos Mexía Reservoir at the Rancho Violante, discovered the skeleton of a theropod new to science.

Description[]

Like the well-known Tyrannosaurus, to which it has been compared, the 6-7 meters (20-23 feet) Gualicho possesses reduced arms and possibly two fingered hands, although a 2020 study suggests enough of the third metacarpal is present for a third finger.

Classification[]

Phylogenetically, Gualicho presents two possibilities; that megaraptorans and neovenatorids were carnosaurs, or that megaraptorans and neovenatorids were a grade of theropods more closely related to coelurosaurs than to carnosaurs.