Ceratosauria

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Ceratosaurs
Temporal range:
Sinemurian-Maastrichtian, 199.3–66  Ma
Ceratosauria Infobox Panoply.png
Six ceratosaurs (top to bottom): Rugops , Elaphrosaurus , Majungasaurus , Carnotaurus , Ceratosaurus , Berthasaura
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Neotheropoda
Clade: Averostra
Clade:† Ceratosauria
Marsh, 1884
Subgroups

Ceratosaurs are members of the clade Ceratosauria, a group of dinosaurs defined as all theropods sharing a more recent common ancestor with Ceratosaurus than with birds. The oldest known ceratosaur, Saltriovenator , dates to the earliest part of the Jurassic, around 199 million years ago. Ceratosauria includes three major clades: Ceratosauridae, Noasauridae, and Abelisauridae, found primarily (though not exclusively) in the Southern Hemisphere. Originally, Ceratosauria included the above dinosaurs plus the Late Triassic to Early Jurassic Coelophysoidea and Dilophosauridae, implying a much earlier divergence of ceratosaurs from other theropods. However, most recent studies have shown that coelophysoids and dilophosaurids do not form a natural group with other ceratosaurs, and are excluded from this group. [1]

Contents

Ceratosauria derives its names from the type species, Ceratosaurus nasicornis , described by O.C. Marsh in 1884. A moderately large predator from the Late Jurassic, Ceratosaurus nasicornis, was the first ceratosaur to be discovered. Ceratosaurs are generally moderately large in size, with some exceptions like the larger Carnotaurus and the significantly smaller noasaurs. The major defining characteristics of Ceratosauria include a robust skull with increased ornamentation or height and a shortening of the arms. [2] Both of these characteristics are generally accentuated in later members of the group, such as the abelisaurs, whereas more basal species such as C. nasicornis appear more similar to other basal theropods. The highly fragmented nature of the ceratosaur fossil record means that the characteristics, relationships, and early history of Ceratosauria remain mysterious and highly debated.

Phylogeny

Historical phylogeny

Ceratosauria was first described by O.C. Marsh in the American Journal of Science in 1884. Writing about the newly discovered C. nasicornis , he noted the similarities between the firmly united metatarsals of C. nasicornis and those of Archaeopteryx . Since C. nasicornis was the only other dinosaur discovered at the time to share this trait, Marsh concluded that Ceratosauria must be placed very near Archaeopteryx and its related groups. [3]

However, the idea of the Ceratosauria was soon contested by Marsh's rival, Edward Drinker Cope. Cope argued that the taxon was invalid. [4] The idea of the Ceratosauria would regain some support more than thirty years later when Gilmore argued in its favor in 1920. Despite Gilmore's support, few species were added to the group following World War I, and little emphasis was placed on it. In fact, the scientific community's most common interaction with Ceratosauria throughout much of the 20th century was the disputation of its existence, performed by the likes of Romer, Lapparent, Lavocat, Colbert, and Charig amongst others.

Ceratosauria's fortune changed in 1986 when Jacques Gauthier, in an attempt to clarify the evolution of birds, grouped the majority of theropods into either Ceratosauria or Tetanurae. In Ceratosauria, he placed the ceratosaurs and coelophysoids. [5] Gauthier's paper brought Ceratosauria's use back in vogue, and by the early 1990s, Abelisauridae had also been included under Ceratosauria. The triumvirate model of ceratosaurs, coelophysoids, and abelisaurids would go unchallenged until the early 2000s. Beginning at the turn of the millennium, a large number of paleontologists began excluding coelophysoids from Ceratosauria. This view is now widely held thanks to several similarities between Ceratosauria and Tetanurae not found in coelophysoids.

Current phylogeny

Skeletal reconstruction of Masiakasaurus Masiakasaurus.JPG
Skeletal reconstruction of Masiakasaurus

Most paleontologists have postulated that Ceratosauria split off from other theropods in the Late Triassic or earliest Jurassic. Despite this, no ceratosaurs have been discovered prior to the Early Jurassic, and even in the Middle Jurassic, species are sparse. Many scientists, such as Carrano and Sampson, have postulated the lack of specimens is due to a poor fossil record, rather than an indictment on the abundance of ceratosaurs at the time. A similarly large gap of specimens exist in the lower Cretaceous, particularly for Abelisauridae. Several recent discoveries of possible ceratosaurs have begun reshaping the phylogeny of Ceratosauria by filling in some of these gaps. Specifically, this has allowed paleontologists to begin altering the sub-groups inside Ceratosauria, in an attempt to find their most basal members.

Currently, most paleontologists agree that Ceratosauria divides into two sub groups, Ceratosauridae and Abelisauroidea, with some variance as to which taxa are placed into basal polytomy. [2] [6] Abelisauroidea is further divided into the Abelisauridae and Noasauridae, with Abelisauridae, including Carnotaurinae. Recently, Rauhut and Carrano have placed Elaphrosaurinae inside Noasauridae while simultaneously moving the previous noasaurs into Noasaurinae. [6] Into their new Noasauridae, they have uniquely included Deltadromeus and Limusaurus .

The oldest known ceratosaur currently described is Saltriovenator zanellai which is dated to the Early Sinemurian, 199-197 Ma. [7] The origin of Ceratosauria could have been in Northern Pangea where Saltriovenator, its close relative Berberosaurus, and Carmelopodus footprints have been found.

The following cladogram follows an analysis by Diego Pol and Oliver W. M. Rauhut, 2012. [2]

Ceratosauria 

A different conclusion was reached in a 2017 paper on Limusaurus ontogeny. Unlike other analyses, Noasauridae was placed more basal than Ceratosaurus , with the latter being within Abelisauridae by definition. [8] This was later expanded on in a 2018 paper on ceratosaur paleobiology, which named a new clade Etrigansauria, which contained the families Abelisauridae and Ceratosauridae. [9] The following cladogram is a consensus tree of the latest phylogenies shown in the paper.

Paleobiology

Anatomy

Some of the defining characteristics of Ceratosauria include an increase in height and ornamentation of the skull, as well as a shortening of the forelimbs. Likewise, ceratosaurs fused their ilium, ischium, and pubis together, as well as the astragalus and calcaneum. [4] For less derived members of the group, such as C. nasicornis , traits such as raising of the skull and shortening of the forelimbs were not as noticeable. The skull of C. nasicornis was rather similar to the basal theropod mold, with a distinguishing nasal crest to go along with lacrimal crests similar to the contemporary Allosaurus . C. nasicornis had larger teeth than Allosaurus, and some paleontologists postulate that it would have had a difficult time attacking larger prey. Abelisaurids, however, carried many of these defining traits to their extremes. Most abelisaurids had largely shortened forelimbs, with Carnotaurus having shrunk them further than any large theropod. [10] After analyzing the features of the newly discovered Rugops primus, Paul Sereno has postulated that many of these abelisaurid features may lend themselves to scavenging. [11] Despite the huge reduction in size, no taxa in Ceratosauria ever lost a digit or any critical elements of the forelimb. Some joint variation has also been observed in Ceratosauria, and it has been postulated that they may have had better shoulder mobility than other large theropods. [1]

Geography

Ceratosaurs appeared to have had a global population that diverged by the early Jurassic. However, they appear to have largely disappeared from Laurasia in the Cretaceous, with those few specimens that have been discovered having been possibly reintroduced from Gondwana. [12] No confirmed specimens of ceratosaurs in North America during the Cretaceous have been found.

Abelisaurids in particular had great success in Gondwana, particularly in the Cretaceous. Some Gondwanan and Laurasian specimens have recently been found and dated to Late Jurassic, and possibly even the Middle Jurassic, greatly extending the abelisaurid timeline. Some paleontologists have postulated that a large desert may have kept abelisaurids locked in southern Gondwana until the late Jurassic. [2] Whether correlation or causation, it has been largely observed that late Cretaceous ceratosaurs were found less in areas dominated by basal tetanurans (Africa) or coelurosaurs (North America and Asia). The below phylogeny follows a simplified cladogram of Hendrickx et al. (2015), limited to Ceratosauria.

Ceratosauria
                      

██ Limusaurus Cartography of Asia.svg

                                      

██ Ceratosaurus Cartography of North America.svg

                  

█ Berberosaurus Cartography of Africa.svg

█ Eoabelisaurus Cartography of South America.svg

                                                      
                                  
     

█ Rugops Cartography of Africa.svg

                  
                      

Diet

As with most theropods, ceratosaurs were carnivores—except for some noasaurs like Limusaurus and Berthasaura , which were omnivores or herbivores with toothless beaks. [13] [14] Ceratosaurus has been argued to have eaten a large amount of fish and other aquatic creatures, though this has been disputed by many paleontologists. [15] Tooth marks on large animals such as Allosaurus indicate that Ceratosaurus likely utilized scavenging often. [16] The interesting jaws of the abelisaurids have drawn mixed dietary predictions. One study on Carnotaurus found that its bite, thanks to its shortened skull, was suited for hunting small prey, thanks to a quick, but relatively weak bite. [17] On the other hand, other groups of paleontologists have found that the bite of Carnotaurus was relatively powerful, and more adept at hunting and wounding large prey. [18] Others have postulated its skull was built for scavenging. The debate over the eating habits of ceratosaurs is quite active, particularly recently with the increase in abelisaur discoveries.

See also

Related Research Articles

<i>Ceratosaurus</i> Genus of theropod dinosaur from the Late Jurassic period

Ceratosaurus was a carnivorous theropod dinosaur that lived in the Late Jurassic period. The genus was first described in 1884 by American paleontologist Othniel Charles Marsh based on a nearly complete skeleton discovered in Garden Park, Colorado, in rocks belonging to the Morrison Formation. The type species is Ceratosaurus nasicornis.

<i>Carnotaurus</i> Genus of dinosaur from the Late Cretaceous period

Carnotaurus is a genus of theropod dinosaur that lived in South America during the Late Cretaceous period, probably sometime between 71 and 69 million years ago. The only species is Carnotaurus sastrei. Known from a single well-preserved skeleton, it is one of the best-understood theropods from the Southern Hemisphere. The skeleton, found in 1984, was uncovered in the Chubut Province of Argentina from rocks of the La Colonia Formation. Carnotaurus is a derived member of the Abelisauridae, a group of large theropods that occupied the large predatorial niche in the southern landmasses of Gondwana during the late Cretaceous. Within the Abelisauridae, the genus is often considered a member of the Brachyrostra, a clade of short-snouted forms restricted to South America.

<span class="mw-page-title-main">Tetanurae</span> Clade containing most theropod dinosaurs

Tetanurae is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans. Tetanurans are defined as all theropods more closely related to modern birds than to Ceratosaurus and contain the majority of predatory dinosaur diversity. Tetanurae likely diverged from its sister group, Ceratosauria, during the late Triassic. Tetanurae first appeared in the fossil record by the Early Jurassic about 190 mya and by the Middle Jurassic had become globally distributed.

<i>Masiakasaurus</i> Noasaurid theropod dinosaur genus from the Late Cretaceous period

Masiakasaurus is a genus of small predatory noasaurid theropod dinosaurs from the Late Cretaceous of Madagascar. In Malagasy, masiaka means "vicious"; thus, the genus name means "vicious lizard". The type species, Masiakasaurus knopfleri, was named after the musician Mark Knopfler, whose music inspired the expedition crew. It was named in 2001 by Scott D. Sampson, Matthew Carrano, and Catherine A. Forster. Unlike most theropods, the front teeth of M. knopfleri projected forward instead of straight down. This unique dentition suggests that they had a specialized diet, perhaps including fish and other small prey. Other bones of the skeleton indicate that Masiakasaurus were bipedal, with much shorter forelimbs than hindlimbs. M. knopfleri was a small theropod, reaching 1.8–2.1 m (5.9–6.9 ft) long and weighing 20 kg (44 lb).

<i>Rugops</i> Genus of dinosaur

Rugops is a monospecific genus of basal abelisaurid theropod dinosaur from Niger that lived during the Late Cretaceous period in what is now the Echkar Formation. The type and only species, Rugops primus, is known only from a partial skull. It was named and described in 2004 by Paul Sereno, Jeffery Wilson and Jack Conrad. Rugops has an estimated length of 4.4–5.3 metres and weight of 410 kilograms. The top of its skull bears several pits which correlates with overlaying scale and the front of the snout would have had an armour-like dermis.

<span class="mw-page-title-main">Abelisauridae</span> Extinct family of dinosaurs

Abelisauridae is a family of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian subcontinent and the island of Madagascar. Isolated teeth were found in the Late Jurassic of Portugal, and the Late Cretaceous genera Tarascosaurus and Arcovenator have been described in France. Abelisaurids first appear in the fossil record of the early middle Jurassic period, and at least three genera survived until the end of the Mesozoic era 66 million years ago.

<i>Deltadromeus</i> Theropod dinosaur genus from mid-Cretaceous Period

Deltadromeus is a genus of theropod dinosaur from the Aoufous Formation of Morocco.

<span class="mw-page-title-main">Abelisauroidea</span> Extinct clade of dinosaurs

Abelisauroidea is a diverse superfamily of ceratosaurian dinosaurs, typically regarded as a Cretaceous group, though the earliest abelisaurid remains are known from the Middle Jurassic of Argentina and possibly Madagascar. Possible Abelisauridae remains were also discovered in Late Jurassic Tendaguru Beds in Tanzania.

<i>Elaphrosaurus</i> Ceratosaurian theropod dinosaur genus from the Late Jurassic Period

Elaphrosaurus is a genus of ceratosaurian theropod dinosaur that lived approximately 154 to 150 million years ago during the Late Jurassic Period in what is now Tanzania in Africa. Elaphrosaurus was a medium-sized but lightly built member of the group that could grow up to 6.2 m (20 ft) long. Morphologically, this dinosaur is significant in two ways. Firstly, it has a relatively long body but is very shallow-chested for a theropod of its size. Secondly, it has very short hindlimbs in comparison with its body. Phylogenetic analyses indicate that this genus is likely a ceratosaur. Earlier suggestions that it is a late surviving coelophysoid have been examined but generally dismissed. Elaphrosaurus is currently believed to be a very close relative of Limusaurus, an unusual beaked ceratosaurian which may have been either herbivorous or omnivorous.

<i>Compsosuchus</i> Extinct genus of dinosaurs

Compsosuchus is a dubious genus of abelisauroid dinosaur from the Late Cretaceous Lameta Formation of India.

<i>Majungasaurus</i> Abelisaurid theropod dinosaur from the Late Cretaceous period

Majungasaurus is a genus of abelisaurid theropod dinosaur that lived in Madagascar from 70 to 66 million years ago, at the end of the Cretaceous Period, making it one of the last-known non-avian dinosaurs that went extinct during the Cretaceous–Paleogene extinction event. The genus contains a single species, Majungasaurus crenatissimus. This dinosaur is also called Majungatholus, a name which is considered a junior synonym of Majungasaurus.

<i>Noasaurus</i> Extinct genus of dinosaurs

Noasaurus is a genus of ceratosaurian theropod dinosaur genus from the late Campanian-Maastrichtian of Argentina. The type and only species is N. leali.

<span class="mw-page-title-main">Ceratosauridae</span> Extinct family of dinosaurs

Ceratosauridae is an extinct family of theropod dinosaurs belonging to the infraorder Ceratosauria. The family's type genus, Ceratosaurus, was first found in Jurassic rocks from North America. Ceratosauridae is made up of the genera Ceratosaurus, found in North America, Tanzania, and Portugal, and Genyodectes, from the Early Cretaceous of Argentina. Unnamed probable ceratosaurids are known from limited material in the Middle Jurassic of Madagascar, the Late Jurassic of Switzerland, the Late Jurassic of Tanzania, and the Late Jurassic or possibly Early Cretaceous of Uruguay.

<span class="mw-page-title-main">Noasauridae</span> Extinct family of dinosaurs

Noasauridae is an extinct family of theropod dinosaurs belonging to the group Ceratosauria. They were closely related to the short-armed abelisaurids, although most noasaurids had much more traditional body types generally similar to other theropods. Their heads, on the other hand, had unusual adaptations depending on the subfamily. 'Traditional' noasaurids, sometimes grouped in the subfamily Noasaurinae, had sharp teeth which splayed outwards from a downturned lower jaw.

<span class="mw-page-title-main">Carnotaurini</span> Extinct tribe of dinosaurs

Carnotaurini is a tribe of the theropod dinosaur family Abelisauridae from the Late Cretaceous period of Patagonia. It includes the dinosaurs Carnotaurus sastrei; the type species, Aucasaurus garridoi, and Abelisaurus comahuensis. This group was first proposed by paleontologists Rodolfo Coria, Luis Chiappe, and Lowell Dingus in 2002, being defined as a clade containing "Carnotaurus sastrei, Aucasaurus garridoi, their most recent common ancestor, and all of its descendants."

<i>Limusaurus</i> Genus of theropod dinosaur

Limusaurus is a genus of theropod dinosaur that lived in what is now China during the Late Jurassic, around 161 to 157 million years ago. The type and only species Limusaurus inextricabilis was described in 2009 from specimens found in the Upper Shishugou Formation in the Junggar Basin of China. The genus name consists of the Latin words for "mud" and "lizard", and the species name means "impossible to extricate", both referring to these specimens possibly dying after being mired. Limusaurus was a small, slender animal, about 1.7 m in length and 15 kg (33 lb) in weight, which had a long neck and legs but very small forelimbs. It underwent a drastic morphological transformation as it aged: while juveniles were toothed, these teeth were completely lost and replaced by a beak with age. Several of these features were convergently similar to the later ornithomimid theropods as well as the earlier non-dinosaurian shuvosaurids.

<i>Eoabelisaurus</i> Extinct genus of dinosaurs

Eoabelisaurus is a genus of abelisaurid theropod dinosaur from the Lower Jurassic Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Argentina, South America. The generic name combines a Greek ἠώς, (eos), "dawn", with the name Abelisaurus, in reference to the fact it represents an early relative of the latter. Only one species is currently recognized, E. mefi; the specific name honours the MEF, the Museo Paleontológico "Egidio Feruglio", where discoverer Diego Pol is active. It is characterized by reduced forelimb proportions that show primitive characteristics of the Abelisauridae family.

<i>Arcovenator</i> Extinct genus of dinosaurs

Arcovenator is an extinct genus of abelisaurid theropod dinosaurs hailing from the Late Cretaceous of France. The type and only described species is Arcovenator escotae.

<span class="mw-page-title-main">Majungasaurinae</span> Extinct subfamily of reptiles

Majungasaurinae is a subfamily of large carnivorous theropods from the Upper Cretaceous, found in Madagascar, India, and France. It is a subgroup within the theropod family Abelisauridae, a Gondwanan clade known for their thick and often horned skulls and vestigial arms. The two subfamilies of Abelisauridae are Carnotaurinae, best known from the South American Carnotaurus, and Majungasaurinae, consisting of Madagascar’s Majungasaurus and its closest relatives. Their ancestors emerged in the Middle Jurassic, and the clade lasted until the Upper Cretaceous.

<span class="mw-page-title-main">Timeline of ceratosaur research</span>

This timeline of ceratosaur research is a chronological listing of events in the history of paleontology focused on the ceratosaurs, a group of relatively primitive, often horned, predatory theropod dinosaurs that became the apex predators of the southern hemisphere during the Late Cretaceous. The nature and taxonomic composition of the Ceratosauria has been controversial since the group was first distinguished in the late 19th century. In 1884 Othniel Charles Marsh described the new genus and species Ceratosaurus nasicornis from the Late Jurassic Morrison Formation of the western United States. He felt that it belonged in a new family that he called the Ceratosauridae. He created the new taxon Ceratosauria to include both the Ceratosauridae and the ostrich-like ornithomimids. The idea of the Ceratosauria was soon contested, however. Later that same decade both Lydekker and Marsh's hated rival Edward Drinker Cope argued that the taxon was invalid.

References

  1. 1 2 Carrano, Matthew T.; Sampson, Scott D. (2008-01-01). "The Phylogeny of Ceratosauria (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 6 (2): 183–236. doi:10.1017/S1477201907002246. ISSN   1477-2019. S2CID   30068953.
  2. 1 2 3 4 Diego Pol & Oliver W. M. Rauhut (2012). "A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs". Proceedings of the Royal Society B: Biological Sciences. 279 (1804): 3170–5. doi:10.1098/rspb.2012.0660. PMC   3385738 . PMID   22628475.
  3. ↑ Marsh, O. C. (1884). "On the united metatarsal bones of Ceratosaurus". American Journal of Science. s3-28 (164): 161–162. Bibcode:1884AmJS...28..161M. doi:10.2475/ajs.s3-28.164.161. S2CID   131737380.
  4. 1 2 Weishampel, David B.; Peter, Dodson; Osmólska, Halszka (2007). The Dinosauria. University of California Press. ISBN   978-0520242098. OCLC   493366196.
  5. ↑ "Saurischian monophyly and the origin of birds". Memoirs of the California Academy of Sciences. 8. 1986. ISSN   0885-4629.
  6. 1 2 Rauhut, Oliver W. M.; Carrano, Matthew T. (2016-11-01). "The theropod dinosaur Elaphrosaurus bambergi, from the Late Jurassic of Tendaguru, Tanzania". Zoological Journal of the Linnean Society. 178 (3): 546–610. doi:10.1111/zoj.12425. ISSN   0024-4082.
  7. ↑ Sasso, Cristiano Dal; Maganuco, Simone; Cau, Andrea (2018-12-19). "The oldest ceratosaurian (Dinosauria: Theropoda), from the Lower Jurassic of Italy, sheds light on the evolution of the three-fingered hand of birds". PeerJ. 6: e5976. doi: 10.7717/peerj.5976 . ISSN   2167-8359. PMC   6304160 . PMID   30588396.
  8. ↑ Wang, S.; Stiegler, J.; Amiot, R.; Wang, X.; Du, G.-H.; Clark, J.M.; Xu, X. (2017). "Extreme Ontogenetic Changes in a Ceratosaurian Theropod" (PDF). Current Biology. 27 (1): 144–148. doi: 10.1016/j.cub.2016.10.043 . PMID   28017609.
  9. ↑ Delcourt, Rafael (2018-06-27). "Ceratosaur palaeobiology: new insights on evolution and ecology of the southern rulers". Scientific Reports. 8 (1): 9730. doi:10.1038/s41598-018-28154-x. ISSN   2045-2322. PMC   6021374 . PMID   29950661.
  10. ↑ Bonaparte, José; Novas, Fernando; Coria, Rodolfo (1990). "Carnotaurus sastrei Bonaparte, the horned, lightly built carnosaur from the Middle Cretaceous of Patagonia. Contributions in Science" (PDF). Natural History Museum of Los Angeles County. 416: 1–42. Archived from the original (PDF) on 2016-06-29. Retrieved 2017-05-31.
  11. ↑ Sereno, Paul C.; Brusatte, Stephen L. (2008). "Basal Abelisaurid and Carcharodontosaurid Theropods from the Lower Cretaceous Elrhaz Formation of Niger". Acta Palaeontologica Polonica. 53 (1): 15–46. doi: 10.4202/app.2008.0102 . hdl: 20.500.11820/5d55ed2e-52f2-4e4a-9ca1-fd1732f2f964 .
  12. ↑ Tortosa, Thierry; Buffetaut, Eric; Vialle, Nicolas; Dutour, Yves; Turini, Eric; Cheylan, Gilles (2014). "A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications". Annales de Paléontologie. 100 (1): 63–86. doi:10.1016/j.annpal.2013.10.003.
  13. ↑ Xu, Xing; Clark, James M.; Mo, Jinyou; Choiniere, Jonah; Forster, Catherine A.; Erickson, Gregory M.; Hone, David W. E.; Sullivan, Corwin; Eberth, David A. (2009-06-18). "A Jurassic ceratosaur from China helps clarify avian digital homologies" (PDF). Nature. 459 (7249): 940–944. Bibcode:2009Natur.459..940X. doi:10.1038/nature08124. ISSN   0028-0836. PMID   19536256. S2CID   4358448.
  14. ↑ de Souza GA, Soares MB, Weinschütz LC, Wilner E, Lopes RT, de Araújo OM, Kellner AW (2021). "The first edentulous ceratosaur from South America". Scientific Reports. 11 (1): Article number 22281. Bibcode:2021NatSR..1122281D. doi: 10.1038/s41598-021-01312-4 . PMC   8602317 . PMID   34795306.
  15. ↑ J., Currie, Philip; B., Koppelhus, Eva; A., Shugar, Martin; L., Wright, Joanna (2004). Feathered dragons : studies on the transition from dinosaurs to birds. Indiana University Press. ISBN   978-0253343734. OCLC   895411495.{{cite book}}: CS1 maint: multiple names: authors list (link)
  16. ↑ "Prey bone utilization by predatory dinosaurs in the Late Jurassic of North America, with comments on prey bone use by dinosaurs throughout the Mesozoic (PDF Download Available)". ResearchGate. Retrieved 2017-05-31.
  17. ↑ Mazzetta, Gerardo V.; Cisilino, Adrián P.; Blanco, R. Ernesto; Calvo, Néstor (2009-09-12). "Cranial mechanics and functional interpretation of the horned carnivorous dinosaur Carnotaurus sastrei". Journal of Vertebrate Paleontology. 29 (3): 822–830. doi:10.1671/039.029.0313. hdl: 11336/34937 . ISSN   0272-4634. S2CID   84565615.
  18. ↑ Kenneth., Carpenter (2005). The carnivorous dinosaurs. Indiana University Press. ISBN   978-0253345394. OCLC   895411496.
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