Aucasaurus

Aucasaurus
Temporal range: Late Cretaceous, 83 Ma
Mounted skeleton reconstruction
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Order: Saurischia
Suborder: Theropoda
Family: Abelisauridae
Clade: Brachyrostra
Tribe: Carnotaurini
Genus: Aucasaurus
Coria, Chiappe & Dingus, 2002
Species:  A. garridoi
Binomial name
Aucasaurus garridoi
Coria, Chiappe & Dingus, 2002

Aucasaurus was a genus of medium-sized theropod dinosaur from Argentina that lived during the Santonian stage of the Anacleto Formation. It was smaller than the related Carnotaurus, although more derived in some ways, such as its extremely reduced arms and almost total lack of fingers.[1] The type skeleton is complete to the thirteenth caudal vertebra, and so is relatively well understood, and is the most complete abelisaurid yet described. However, the skull is damaged, causing some paleontologists to speculate that it was involved in a fight prior to death.

Description

Life restoration

Aucasaurus short, deep-snouted skull was not as short or as deep-snouted as that of Carnotaurus. Also, instead of horns, it had a pair of low ridges above each eye.[2]

Forelimbs and Hands

Aucasaurus small arms were also alike that of its horned relative, but were proportionally longer due to its small size, and the bones lacked the bony processes and some unusual proportions present in Carnotaurus. The hand of Aucasaurus was unusual: four metacarpals were present, but the first and fourth lacked fingers. The second and third had fingers, but they were quite short and had no claws.[2]

Discovery

Aucasaurus is known from finds in the Rio Colorado Formation, a Late Cretaceous formation in Argentina that has yielded many dinosaur fossils. Numerous sauropod eggs are also known from this deposit.[2]

Classification

3D scan of the braincase

Aucasaurus was closely related to Carnotaurus and they are united in the Carnotaurini.[2]

Below is a cladogram by Canalle et al. in 2009.[3]

Carnotaurinae

Majungasaurus


Brachyrostra
Carnotaurini

Aucasaurus



Carnotaurus





Ilokelesia




Skorpiovenator



Ekrixinatosaurus






In popular culture

Size compared to a human

This dinosaur was featured in the Discovery Channel series Dinosaur Planet, where it was depicted as a pack hunter and ate the sauropod Saltasaurus. In the episode, the head injury discovered in the type specimen was interpreted as being crushed by a stumbling Saltasaurus.

See also

References

  1. Coria, R. A.; Chiappe, L. M.; Dingus, L. (2002). "A new close relative of Carnotaurus sastrei Bonaparte 1985 (Theropoda: Abelisauridae) from the Late Cretaceous of Patagonia". Journal of Vertebrate Paleontology 22 (2): 460. doi:10.1671/0272-4634(2002)022[0460:ANCROC]2.0.CO;2.
  2. 1 2 3 4 Benton, Michael J. (2012). Prehistoric Life. Edinburgh, Scotland: Dorling Kindersley. p. 320. ISBN 978-0-7566-9910-9.
  3. Canale, J. I.; Scanferla, C. A.; Agnolin, F. L.; Novas, F. E. (2008). "New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods". Naturwissenschaften 96 (3): 409–414. Bibcode:2009NW.....96..409C. doi:10.1007/s00114-008-0487-4. PMID 19057888.

External links

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