Carnotaurinae

Carnotaurinae
Skeleton cast of Carnotaurus in the Chlupáč Museum in Prague .
Temporal occurrence
Upper Cretaceous ( Cenomanian to Maastrichtian )
100.5 to 66 million years
Locations
South America ( Argentina ) Madagascar India
Systematics
Lizard dinosaur (Saurischia) Theropoda Ceratosauria Abelisauroidea Abelisauridae Carnotaurinae
Scientific name
Carnotaurinae
Sereno , 1998

The Carnotaurinae are a subfamily of the Abelisauridae within the theropod dinosaurs . It summarizes the derived (advanced) representatives of the Abelisauridae, such as Carnotaurus , Aucasaurus , Majungasaurus and Rajasaurus . Representatives of the Carnotaurinae come from the Upper Cretaceous ( Cenomanian to Maastrichtian ) of Madagascar , India and Argentina .

Definition and validity

The Carnotaurinae was first proposed in 1998 by the American paleontologist Paul Sereno . It is defined as a clade containing all taxa more closely related to Carnotaurus than to Abelisaurus . Since Abelisaurus is regarded as the original (basal) Abelisauridae in most analyzes, the Carnotaurinae summarize all derived Abelisauridae.

The taxon Carnotaurinae is not accepted by all researchers. In contrast to other studies, Carrano and Sampson (2008) come to the conclusion that Abelisaurus is actually a derivative of the Abelisauridae. According to this analysis, the Carnotaurinae, following the definition, would only include the genera Carnotaurus and Ilokelesia .

features

Horn-like structures on the skullcap are known from various representatives of the Carnotaurinae. While Carnotaurus has a pair of almost 15 cm long horns extending from the frontal bone , Majungasaurus has a single extension on the frontal bone. Scorpiovenator and Ekrixinatosaurus only show an elevated postorbital region. Paul Sereno and colleagues (2004) suspect that horn-like structures represent an apomorphy (newly acquired feature) of the Carnotaurinae. Canale and colleagues (2009) disagree, however, and assume that this feature is not homologous , but developed several times independently of one another ( convergent ). They argue that the horn-like structures in different genera differ in terms of their position and are formed by different bones.

Internal system

The relationships within the Carnotaurinae are controversial. With the Carnotaurini and the Brachyrostra two subgroups were established, which are not generally accepted.

Carnotaurini

The Carnotaurini were proposed by researchers around Rodolfo Coria (2002) as a new group within the Carnotaurinae. It is defined as node-based taxon ( node based definition ), the last common ancestor of Carnotaurus sastrei and Aucasaurus garridoi and includes all descendants of this ancestor. The researchers conclude that Aucasaurus is the sister genus of Carnotaurus ; thus the Carnotaurini only include these two genera. Paul Sereno (2005) does not recognize this group because the systematic position of Aucasaurus and thus the content of this group is unclear.

Brachyrostra

Juan Canale and colleagues (2009) propose a new group within the Carnotaurinae, the Brachyrostra ( gr. Brachy - "short", Latin rostrum - "snout"). This group is intended to include all carnotaurines that have a proportionally short snout, a heavily ornamented skull and reduced eye sockets. Canale and colleagues assign the Brachyrostra genera Carnotaurus , Aucasaurus , Ilokelesia , Ekrixinatosaurus and Scorpiovenator . The genus Majungasaurus , which has a proportionally longer snout, forms the sister group . The Brachyrostra are defined as a clade that includes all taxa more closely related to Carnotaurus sastrei than to Majungasaurus crenatissimus .

The following is a cladogram according to Canale and colleagues (2009):

Carnotaurinae	Majungasaurus  Brachyrostra    Carnotaurini   Carnotaurus     Aucasaurus     Ilokelesia     Scorpiovenator     Ekrixinatosaurus

supporting documents

literature

• Juan I. Canale, Carlos A. Scanferla, Federico L. Agnolin, Fernando E. Novas : New carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution of abelisaurid theropods. In: The natural sciences . Vol. 96, No. 3, 2009, pp. 409-414, doi : 10.1007 / s00114-008-0487-4 .
• Ariana Paulina Carabajal: The braincase anatomy of Carnotaurus sastrei (Theropoda: Abelisauridae) from the Upper Cretaceous of Patagonia. In: Journal of Vertebrate Paleontology. Vol. 31, No. 2, 2011, ISSN  0272-4634 , pp. 378-386, doi : 10.1080 / 02724634.2011.550354 .
• Matthew T. Carrano, Scott D. Sampson: The Phylogeny of Ceratosauria (Dinosauria: Theropoda). In: Journal of Systematic Palaeontology. Vol. 6, No. 2, 2008, ISSN  1477-2019 , pp. 183-236, doi : 10.1017 / S1477201907002246 .
• Rodolfo A. Coria , Luis M. Chiappe , Lowell Dingus : A new close relative of Carnotaurus sastrei Bonaparte 1985 (Theropoda: Abelisauridae) from the Late Cretaceous of Patagonia. In: Journal of Vertebrate Paleontology. Vol. 22, Vol. 2, 2002, pp. 460-465, doi : 10.1671 / 0272-4634 (2002) 022 [0460: ANCROC] 2.0.CO; 2 .
• Paul C. Sereno : A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. In: New Yearbook for Geology and Paleontology. Treatises. Vol. 210, No. 1, 1998, ISSN  0077-7749 , pp. 41-83.
• Paul C. Sereno, Jeffrey A. Wilson, Jack L. Conrad: New dinosaurs link southern landmasses in the Mid-Cretaceous. In: Proceedings of the Royal Society. Series C: Biological Sciences. Vol. 271, No. 1546, 2004, pp. 1325-1330, doi : 10.1098 / rspb.2004.2692 .

Individual evidence

1. ↑ Sereno 1998
2. ^ Paul Sereno: Carnotaurinae. (No longer available online.) In: Taxon Search. Archived from the original on May 16, 2012 ; Retrieved August 3, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
3. ↑ ^{a b} Carrano and Sampson , p. 202
4. ↑ Carabajal 2011 , p. 379
5. ↑ Sereno et al. 2004
6. ↑ Canale et al. 2009 , pp. 1, 5
7. ↑ Coria et al. 2002 , p. 460
8. ^ Paul Sereno: Carnotaurini. (No longer available online.) In: Taxon Search. Archived from the original on May 16, 2012 ; Retrieved August 3, 2014 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
9. ↑ Canale et al. 2009
10. ↑ Canale et al. 2009 , Supplementary Material, pp. 1-2