Kingdom Animalia Clade Dinosauria Clade †Carcharodontosauria Phylum Chordata Order Saurischia | Class Reptilia Suborder Theropoda Family †Neovenatoridae Rank Species | |
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Similar Murusraptor, Megaraptora, Dracoraptor, Timurlengia, Neovenatoridae | ||
Gualicho (named in reference to the gualichu) is a genus of theropod dinosaur. The type species is Gualicho shinyae. Gualicho lived in what is now northern Patagonia, on what was then a South American island continent split off from the supercontinent Gondwana. The fossils were found in the Huincul Formation, dating to the late Cenomanian-early Turonian age of the upper Cretaceous Period, around 93 million years ago.
Contents
Gualicho los redondos
Description
Like the well-known Tyrannosaurus, to which it has been compared, the 6–7 m (20–23 ft) Gualicho possesses reduced arms and two fingered hands. This finding indicates that carnosaurs were subject to the same evolution of limb-reduction as tyrannosaurids and abelisaurids.
Discovery
On 13 February 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. In 2016, the specimen was named and described by Sebastián Apesteguía, Nathan D. Smith, Rubén Juárez Valieri and Peter J. Makovicky. The generic name is derived from the gualichu, a demon of local folklore. The specific name honours Shinya as the animal's discoverer.
The holotype, MPCN PV 0001, consists of a partial skeleton lacking the skull. It contains four vertebrae of the back, three vertebrae of the middle tail, ribs, a basket of belly-ribs, the left shoulder girdle, the left forelimb, the right lower arm, the lower ends of both pubic bones, the right thighbone, the lower end of the left thighbone, the upper ends of the right shinbone and calf bone, elements of both metatarsi and three toes of the right foot. Most bones were uncovered in their original anatomical position but much of the skeleton had been destroyed by erosion.
Gualicho has been suggested to be synonymous with the megaraptoran Aoniraptor, also known from Huincul Formation and uncovered at the Violante site in view of similarities in their caudal vertebrae. However, Aoniraptor does not meet the requirements of ICZN Article 8.5.3, meaning it is an invalid nomen nudum.
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.
The cladogram below follows a 2016 analysis by Sebastián Apesteguía, Nathan D. Smith, Rubén Juarez Valieri, and Peter J. Makovicky.