Aucasaurus

Skeletal reconstruction of Aucasaurus

• Neuquén, Argentina ( Anacleto Formation)

• Aucasaurus garridoi

Aucasaurus is a genus theropod dinosaur from the group of Abelisauridae. The only known skeleton is from the Upper Cretaceous (Lower than average Campanian ) of the Argentine reference Auca Mahuevo, which is famous for its numerous finds of Sauropodeneiern and embryos. It is a well-preserved, nearly complete skeleton including skin and tissue imprints. This finding provides insight into different yet poorly understood aspects of the anatomy of the Abelisauridae, above all the greatly reduced arms, and therefore has a high scientific value. Aucasaurus was described in 2002 by researchers led by Rodolfo Coria with the only kind Aucasaurus garridoi preliminary scientific. A detailed description is currently being prepared (as of 2008 ).

The name Aucasaurus comes from the Mapuche language and has the locality Auca Mahuevo. The second part of the species name, garridoi honors Alberto Garrido, the discoverer of the skeleton.

Features

Aucasaurus was like other Abelisauriden a bipedal carnivore with a relatively short skull and short, reduced arms. The skeleton found is 30% smaller than that of the closely related Carnotaurus. The legs were relatively slim - similar to Carnotaurus, but unlike Majungasaurus. Compared with Carnotaurus Aucasaurus was less specialized: while Carnotaurus a pair of large, from the frontal bone ( frontal ) has outgoing brow horns, only low projections were trained at Aucasaurus. The muzzle, which is higher than long in Carnotaurus is longer at Aucasaurus in proportion. The arms were shortened in two genera; relative to the femur, however, the arms were longer than those of Carnotaurus at Aucasaurus.

The metacarpal bones ( metacarpals ) are as articulated directly with the forearm in Carnotaurus; Carpal bones ( carpal bones ) are missing. The hand is vierstrahlig: the first and fourth beam consisting only of a respective metacarpal bone, while the second and third beam, respectively, and two small finger bone ( phalanx ) have. As with Carnotaurus the fourth metacarpal shows a conical end. However, in Aucasaurus is the first metacarpal bone, the longest bone of the hand, not the fourth as in Carnotaurus.

System

Aucasaurus is often classified within the Abelisauridae as a sister genus of Carnotaurus.

Discovery

The only skeleton was discovered in March 1999 during a paleontological expedition. The skeleton ( holotype, specimen number MCF- PVPH -236 ) was found lying in the anatomical network and on the right side. It probably belonged to an adult individual, after which the degree of fusion of individual sutures suggesting the skeleton.

Documents

Used literature

• JI Canale, CA Scanferla, FL Agnolin and FE Novas: New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods. In: Natural Sciences. Vol 96, No. 3, 2009, pp. 409-414, doi: 10.1007/s00114-008-0487-4.
• Matthew T. Carrano, Scott D. Sampson: The Phylogeny of Ceratosauria ( Dinosauria: Theropoda ). In: Journal of Systematic Palaeontology. 6, 2008, pp. 183-236, doi: 10.1017/S1477201907002246.
• RA Coria, LM Chiappe, L. Dingus: A new close relative of Carnotaurus sastrei Bonaparte 1985 ( Theropoda: Abelisauridae ) from the Late Cretaceous of Patagonia. In: Journal of Vertebrate Paleontology. 22, No. 2, 2002, pp. 460-465.
• Javier Ruiz, Angélica Torices, Humberto Serrano, Valle López: The hand structure of Carnotaurus sastrei ( Theropoda, Abelisauridae ): implications for hand diversity and evolution in abelisaurids. In: Palaeontology. 54, No. 6, October 1, 2011, pp. 1271-1277, doi: 10.1111/j.1475-4983.2011.01091.x ().