Xenotarsosaurus

Zee-noe-tsr-so-sore-us.
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Lilah Turner

Evolutionary Biologist

Lilah Turner investigates how prehistoric animals adapted to changing environments, offering insights into evolution's mechanisms.

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Name

Xenotarsosaurus ‭(‬Strange tarsus lizard‭).

Phonetic

Zee-noe-tsr-so-sore-us.

Named By

Ricardo Mart�nez,‭ ‬Olga Gim�nez,‭ ‬Jorge Rodr�guez‭ & ‬Graciela Bochatey‭ ‬-‭ ‬1986.

Classification

Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Saurischia,‭ ‬theropoda,‭ ‬Abelisauridae‭?

Diet

Carnivore.

Species

X.‭ ‬bonapartei‭

Size

Roughly estimated to be about 5.4 meters long.

Known locations

Argentina,‭ ‬Chubut Province‭ ‬-‭ ‬Bajo Barreal Formation.

Time Period

Cenomanian to Turonian of the Cretaceous.

Fossil representation

Two anterior dorsal‭ (‬back‭) ‬vertebrae and a right hind limb.

In Depth

       Based upon fossil remains first discovered in‭ ‬1980,‭ ‬Xenotarsosaurus was named because‭ ‬of‭ ‬the complete fusion between the astragalus and calcaneum bones of the ankle,‭ ‬something that is quite unusual for a theropod dinosaur.‭ ‬At the time of the original description,‭ ‬the rear leg of Xenotarsosaurus was shown to share some similarities with the better known Carnotaurus,‭ ‬logically leading to the identification of Xenotarsosaurus as an abelisaurid.‭ ‬However a‭ ‬1989‭ ‬study Coria et al.‭ ‬led to an alternative notion that Xenotarsosaurus may in fact be an indeterminate neoceratosaurian theropod.‭ ‬Additionally at the time of its original description,‭ ‬Xenotarsosaurus was thought to come from the Campanian of the Cretaceous,‭ ‬but a later re-assessment of the Bajo Barreal Formation now means that Xenotarsosaurus actually lived during the Cenomanian/Turonian stages of the Cretaceous.

       Xenotarsosaurus was likely one of the principal predators of the Bajo Barreal Formation,‭ ‬with possible prey species including the hadrosaurid Secerosaurus,‭ ‬and titanosaurian sauropods like Drusilasaura.

Further Reading

-‭ ‬Xenotarsosaurus bonapartei nov.‭ ‬gen.‭ ‬et sp.‭ (‬Carnosauria,‭ ‬Abelisauridae‭)‬,‭ ‬un nuevo Theropoda de la Formacion Bajo Barreal,‭ ‬Chubut,‭ ‬Argentina‭ ‬-‭ ‬Ricardo Mart�nez,‭ ‬Olga Gim�nez,‭ ‬Jorge Rodr�guez‭ & ‬Graciela Bochatey‭ ‬-‭ ‬1986. -‭ ‬Sobre Xenotarsosaurus bonapartei Mart�nez,‭ ‬Gim�nez,‭ ‬Rodr�guez y Bochatey,‭ ‬1986‭; ‬un problematico Neoceratosauria‭ (‬Novas,‭ ‬1989‭) ‬del Cret�cico de Chubu‭ ‬-‭ ‬R.A.‭ ‬Coria‭ & ‬J.‭ ‬Rodr�guez‭ ‬-‭ ‬1993. – Allometry and body length of abelisauroid theropods: Pycnonemosaurus nevesi is the new king. – Cretaceous Research. 69: 71–89. – O. N. Grillo & R. Delcourt – 2016

SPECIES SPOTLIGHT