|Skull of Acrocanthosaurus atokensis, North Carolina Museum of Natural Sciences|
Deperet & Savornin, 1925
Carcharodontosaurids (from the Greek καρχαροδοντόσαυρος, carcharodontósauros: "shark-toothed lizards") were a group of carnivorous theropod dinosaurs. In 1931 Ernst Stromer named Carcharodontosauridae as a family, which, in modern paleontology, indicates a clade within Carnosauria. Carcharodontosaurids included some of the largest land predators ever known: Giganotosaurus, Mapusaurus, Carcharodontosaurus, and Tyrannotitan all rivaled or possibly slightly exceeded Tyrannosaurus in length. A 2015 paper by Christophe Hendrickx and colleagues gives a maximum length estimate of 14 meters (46 feet) for the largest carcharodontosaurids, while the smallest carcharodontosaurids were estimated to have been at least 6 meters (20 feet) long.
Along with the spinosaurids, carcharodontosaurids were the largest predators in the early and middle Cretaceous throughout Gondwana, with species also present in North America (Acrocanthosaurus), Europe (Concavenator) and Asia (Shaochilong). Carcharodontosaurids range throughout the Cretaceous from the Barremian (127-121 million years ago) to the Turonian (93-89 million years ago). Past the Turonian, they might have been replaced by the smaller abelisaurids in Gondwana and by tyrannosaurids in North America and Asia. According to Fernando Novas and colleagues, the disappearance of not only carcharodontosaurids but also spinosaurids and other fauna in both Gondwana and North America seem to indicate that this faunal replacement occurred on a global scale. While some teeth and a maxilla discovered in Maastrichtian deposits of Brazil have been assigned to carcharodontosaurids, possibly extending their range, this identification has been subsequently rejected and the material assigned to abelisaurids after better examination. In December 2011, Oliver W. M. Rauhut described a new genus and species of carcharodontosaurid from the Late Jurassic (late Kimmeridgian to earliest Tithonian faunal stage, about 154-150 million years ago) of Tendaguru Formation, southeastern Tanzania. This genus, Veterupristisaurus represents the oldest known carcharodontosaurid.
The family Carcharodontosauridae was originally named by Ernst Stromer in 1931 to include the single newly discovered species Carcharodontosaurus saharicus. A close relative of C. saharicus, Giganotosaurus, was added to the family when it was described in 1995. Additionally, many paleontologists have included Acrocanthosaurus in this family (Sereno et al. 1996, Harris 1998, Holtz 2000, Rauhut 2003, Eddy & Clarke, 2011, Rauhut 2011), though others place it in the related family Allosauridae (Currie & Carpenter, 2000; Coria & Currie, 2002). Carcharodontosaurids are characterized by the following morphological characters : Dorsoventral depth of anterior maxillary interdental plates more than twice anteroposterior width, squared, sub-rectangular anterior portion of the dentary, teeth with wrinkled enamel surfaces, presence of four premaxillary alveoli and a premaxillary body taller than long in lateral aspect, opisthocoelous cervical vertebrae with neural spines more than 1.9 times the height of the centrum, large, textured rugosities on the lacrimal and postorbital formed by roofing and forming broad orbital shelves, and a proximomedially inclined femoral head. With the discovery of Mapusaurus in 2006, Rodolfo Coria and Phil Currie erected a subfamily of Carcharodontosauridae, the Giganotosaurinae, to contain the most advanced South American species, which they found to be more closely related to each other than to the African and European forms. Coria and Currie did not formally refer Tyrannotitan to this subfamily, pending a more detailed description of that genus, but noted that based on characteristics of the femur, it may be a gigantosaurin as well.
In 1998 Paul Sereno defined Carcharodontosauridae as a clade, consisting of Carcharodontosaurus and all species closer to it than to either Allosaurus, Sinraptor, Monolophosaurus, or Cryolophosaurus. Therefore, this clade is by definition outside of the clade Allosauridae. The cladogram below follows the analysis of Brusatte et al., 2009.
Cladogram after Ortega et al., 2010
Cladogram after Novas et al., 2013
The placement of Acrocanthosaurus is unclear, with most researchers favoring Carcharodontosauridae and others favoring Allosauridae. In 2011, a redescription of Kelmayisaurus by Stephen L. Brusatte, Roger B. J. Benson and Xing Xu found it to be valid genus of Carcharodontosauridae. A phylogenetic analysis of Tetanurae recovered K. petrolicus as a basal carcharodontosaurid in a trichotomy with Eocarcharia and a clade comprising more derived carcharodontosaurids. Bahariasaurus has also been proposed as a carcharodontosaurid, but its remains are too scarce to be certain.
Carcharodontosaurids have been proposed as more closely related to abelisaurids, as opposed to the allosaurids. This is due to these two clades sharing some cranial features (see link below). However, these similarities appear to derive from parallel evolution between these two groups. A larger number of cranial and postcranial characters support their relationship with allosaurids.
- Rodrigo P. Fernandes de Azevedo; Felipe Medeiros Simbras; Miguel Rodrigues Furtado; Carlos Roberto A. Candeiro & Lílian Paglarelli Bergqvist (2013). "First Brazilian carcharodontosaurid and other new theropod dinosaur fossils from the Campanian–Maastrichtian Presidente Prudente Formation, São Paulo State, southeastern Brazil". Cretaceous Research. 40: 131–142. doi:10.1016/j.cretres.2012.06.004.
- Stephen L. Brusatte; Roger B. J. Benson; Xing Xu (2012). "A reassessment of Kelmayisaurus petrolicus, a large theropod dinosaur from the Early Cretaceous of China" (PDF). Acta Palaeontologica Polonica. 57 (1): 65–72. doi:10.4202/app.2010.0125.
- Novas, Fernando E. (2013). "Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia". Cretaceous Research. 45: 174–215. doi:10.1016/j.cretres.2013.04.001.
- "Hendrickx, Christophe; Hartman, Scott A.; Mateus, Octávio (2015): An Overview of Non- Avian Theropod Discoveries and Classification. PalArch's Journal of Vertebrate Palaeontology, 12 (1) pp. 1-73". Cite journal requires
- Brusatte, S., Benson, R., Chure, D., Xu, X., Sullivan, C., and Hone, D. (2009). "The first definitive carcharodontosaurid (Dinosauria: Theropoda) from Asia and the delayed ascent of tyrannosaurids." Naturwissenschaften, doi:10.1007/s00114-009-0565-2 PMID 19488730
- Novas, de Valais, Vickers-Rich, and Rich. (2005). "A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids." Naturwissenschaften,
- Carlos Roberto Candeiro; Philip Currie; Lílian Bergqvist (2012). "Theropod teeth from the Marília Formation (late Maastrichtian) at the Paleontological Site of Peirópolis in Minas Gerais State, Brazil". Revista Brasileira de Geociências. 42 (2): 323–330. doi:10.5327/z0375-75362012000200008. Archived from the original on 2014-02-22.
- Delcourt, R.; Grillo, O.N. (2017). "Carcharodontosaurids remained extinct in the Campanian-Maastrichtian: Reassessment of a fragmentary maxilla from Presidente Prudente Formation, Brazil". Cretaceous Research. 84: 515–524. doi:10.1016/j.cretres.2017.09.008.
- Rauhut, Oliver W. M. (2011). "Theropod dinosaurs from the Late Jurassic of Tendaguru (Tanzania)". Special Papers in Palaeontology. 86: 195–239. doi:10.1111/j.1475-4983.2011.01084.x (inactive 2020-01-22).
- Ortega, F.; Escaso, F.; Sanz, J. L. (2010). "A bizarre, humped Carcharodontosauria (Theropoda) from the Lower Cretaceous of Spain" (PDF). Nature. 467 (7312): 203–206. Bibcode:2010Natur.467..203O. doi:10.1038/nature09181. PMID 20829793.
- Eddy, DR; Clarke, JA (2011). "New Information on the Cranial Anatomy of Acrocanthosaurus atokensis and Its Implications for the Phylogeny of Allosauroidea (Dinosauria: Theropoda)". PLoS ONE. 6 (3): e17932. Bibcode:2011PLoSO...617932E. doi:10.1371/journal.pone.0017932. PMC 3061882. PMID 21445312.
- Coria, R.A.; Currie, P.J. (2006). "A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina". Geodiversitas. 28 (1): 71–118.
- Carcharodontosauridae/Abelisauridae 2