Timeline of ceratosaur research

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.[1] In 1884 Othniel Charles Marsh described the new genus and species Ceratosaurus nasicornis from the Late Jurassic Morrison Formation of the western United States.[2] 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.[3] 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.[3]

Skeletal mount of Ceratosaurus nasicornis

The idea of the Ceratosauria would regain some support more than thirty years later when Gilmore argued in its favor in 1920. Nevertheless, the validity of Ceratosauria was disputed throughout much of the 20th century by researchers like Romer, Lapparent, Lavocat, Colbert, and Charig. However, in 1986, more than a century after Marsh first coined the name, Jacques Gauthier revived the idea. Three years later, Rowe published a new definition of Ceratosauria, all taxa more closely related to Ceratosaurus than to birds, based on Gauthier's use of the term. This modern use of the term was thought to include the many theropods discovered since the 1880s known as coelophysoids.[3] Ceratosaurus itself had loose joints between bones in the skull whose interpretation has been controversial. Paleontologist Robert T. Bakker has interpreted this condition as an adaptation to swallow prey larger than it would otherwise be able to fit through its jaws.[4]

Since the 1980s, major developments in ceratosaur taxonomy have centered on the discovery of the Abelisauridae, a new family of large ceratosaurs that were among the dominant predators of the southern hemisphere during the Cretaceous.[5] One of the most notable of these was Carnotaurus, an unusual horned theropod with a short face.[4] More recent noteworthy non-abelisaur ceratosaur discoveries include the protruding-toothed noasaurid Masiakasaurus knopfleri, named after the lead guitarist from Dire Straits.[6]

19th century

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Ceratosaurus nasicornis skeleton restoration by O.C. Marsh from 1896, depicted in an erroneous upright position

1880s

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1884

1888

1890s

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1892

  • Cope rejected the validity of the Ceratosauria and Ceratosauridae.[3]

1896

20th century

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1900s

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1901

 
Illustration of the type specimen of Genyodectes serus

1910s

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1919

  • Othenio Abel rejected the validity of the Ceratosauria and Ceratosauridae.[3]

1920s

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Skeletal restoration of known elements of Elaphrosaurs

1920

1921

 
Type specimen of Sarcosaurus woodi

1925

1930s

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1931

1932

1933

1950s

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1955

 
Neotype specimen of M. crenatissimus (MNHN.MAJ 1), the right dentary of a subadult individual, Muséum national d'histoire naturelle, Paris.

1956

  • Romer rejected the validity of the Ceratosauria and Ceratosauridae.[3]
  • Von Huene recognized the Ceratosauria and/or Ceratosauridae as valid.[3]

1960s

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1964

  • Colbert rejected the validity of the Ceratosauria and Ceratosauridae.[3]

1966

  • Romer rejected the validity of the Ceratosauria and Ceratosauridae.[3]

1970s

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1970

  • Rodney Steel rejected the validity of the Ceratosauria and Ceratosauridae.[3]

1979

 
The type specimen of "Majungatholus", a Majungasaurus snout bump originally mistaken for a pachycephalosaur skull dome

1980s

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1980

1985

 
Skull of Carnotaurus sastrei

1986

  • Robert T. Bakker thought the loose joints in the skull of Ceratosaurus was an adaptation allowing it to swallow prey that would otherwise be too large.[4]
  • Ricardo Martínez and others described the new genus and species Xenotarsosaurus bonapartei.[9]
  • Gauthier "resurrected the name Ceratosauria" to apply to the sister group of the tetanuran theropods. However, while he listed the members of his Ceratosauria, he did not propose a formal phylogenetic definition.[3]

1989

  • Rowe formally defined the Ceratosauria as theropods more closely related to Ceratosaurus nasicornis than birds, based on Gauthier's 1986 usage of the term.[3]

1990s

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Femur of Tarascosaurus salluvicus
 
Artistic restoration of Velocisaurus unicus

1990

  • Rowe and Gauthier published a node-based definition of Ceratosauria.[3]

1991


1994

  • Thomas Holtz named the Coelophysoidea, then thought to be ceratosaurs. He defined them as all theropods more closely related to Coelophysis than to Ceratosaurus. Holtz defined the Neoceratosauria as all theropods closer to Ceratosaurus than to Coelophysis. He also defined the ceratosaur subclade Abelisauroidea as all theropods closer to Carnotaurus sastrei than to Ceratosaurus nasicornis.[3]

1995

1996

1998

 
Restoration of Majungasaurus based on the complete specimen described in 1998.
  • Coria and Leonardo Salgado described the new genus and species Ilokelesia aguagrandensis.[9]
  • Sereno redefined Ceratosauria as all neotheropods closer to Coelophysis bauri than to birds. However, this definition never received broad acceptance by the scientific community because the Rowe had already defined the group in 1989, and therefore had priority.[3] He also split the Abelisauridae into two subfamilies; the Abelisaurinae (all abelisaurids more closely related to Abelisaurus than to Carnotaurus) and Carnotaurinae (all abelisaurids more closely related to Carnotaurus than to Abelisaurus).[3]
  • Sampson and others described a more complete specimen of Majungatholus atops. They performed an X-ray CT scan of the skull of Majungatholus atopus. They found that the dome on the animal's skull formed of its frontal bone was actually hollow. This suggests that this structure was purely for display rather than used in fights between Majungatholus.[4]


21st century

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2000s

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Restored skull of Masiakosaurus knopfleri

2000

2001

  • Sampson, Carrano, and Forster described the new genus and species Masiakasaurus knopfleri.[9] They noted that at least six individuals were preserved together. This makes Masiakasaurus the first neoceratosaur to be preserved in association with others of its species.[10]

2002

 
Skeletal mount of Aucasaurus garridoi

2003

2004

2006

 
Artistic restoration of Limusaurus inextricabilis

2007

2008

2009

2010s

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Artistic restoration of Eoabelisaurus

2010

2012

2013

 
Artistic restoration of Arcovenator

2014

2016

2017

2018

2019

2020s

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2020

See also

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Footnotes

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  1. ^ Tykoski and Rowe (2004); "Introduction", page 47. Also cf. "Systematics and Evolution", page 64.
  2. ^ a b Tykoski and Rowe (2004); "Table 3.1: Ceratosauria", pages 48–49.
  3. ^ a b c d e f g h i j k l m n o p q r s t u v w x y Tykoski and Rowe (2004); "Systematics and Evolution", page 64.
  4. ^ a b c d e Tykoski and Rowe (2004); "Paleobiology", page 69.
  5. ^ Holtz (1999"South American Discoveries: Keys to Dinosaur Evolution", pages 48–49.
  6. ^ Sampson (2009); For description and naming, see "Dramatis Dinosaurae", pages 36–37. For family membership, see "Drifting Continents and Globe-Trotting Dinosaurs" page 59.
  7. ^ a b c d e f g h i j k l Tykoski and Rowe (2004); "Table 3.1: Ceratosauria", page 50.
  8. ^ Tykoski and Rowe (2004); "Table 3.1: Ceratosauria", page 48.
  9. ^ a b c d e f g h i j k l m Tykoski and Rowe (2004); "Table 3.1: Ceratosauria", page 49.
  10. ^ Tykoski and Rowe (2004); "Paleobiology", page 70.
  11. ^ Kellner and Campos (2002); "Abstract", page 163.
  12. ^ Wilson et al. (2003); "Abstract", page 1.
  13. ^ Calvo, Rubilar-Rogers and Moreno (2004); "Abstract", page 555.
  14. ^ Sereno, Wilson, and Conrad (2004); "Abstract", page 1325.
  15. ^ Allain et al. (2007); "Abstract", page 610.
  16. ^ Sereno and Brusatte (2008); "Abstract", page 15.
  17. ^ Canale et al. (2008); "Abstract", page 409.
  18. ^ Xu et al. (2009); "Abstract", page 940.
  19. ^ Ezcurra, Agnolin, and Novas (2010); "Abstract", page 1.
  20. ^ Novas et al. (2010); "Abstract", page 45.
  21. ^ Pol and Rauhut (2012); "Abstract", page 3170.
  22. ^ Farke and Sertich (2013); "Abstract", page 1.
  23. ^ Tortosa et al. (2013); "Abstract", page 63.
  24. ^ Sánchez-Hernández and Benton (2014); "Abstract", page 581.
  25. ^ Dalman (2014); "Abstract", page 181.
  26. ^ Fillippi et al. (2016); in passim.
  27. ^ Nicholas R. Longrich; Xabier Pereda-Suberbiola; Nour-Eddine Jalil; Fatima Khaldoune; Essaid Jourani (2017). "An abelisaurid from the latest Cretaceous (late Maastrichtian) of Morocco, North Africa". Cretaceous Research. 76: 40–52. Bibcode:2017CrRes..76...40L. doi:10.1016/j.cretres.2017.03.021.
  28. ^ Cristiano Dal Sasso; Simone Maganuco; Andrea Cau (2018). "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. PMC 6304160. PMID 30588396.
  29. ^ Rafael Delcourt; Fabiano Vidoi Iori (2018). "A new Abelisauridae (Dinosauria: Theropoda) from São José do Rio Preto Formation, Upper Cretaceous of Brazil and comments on the Bauru Group fauna". Historical Biology: An International Journal of Paleobiology. 32 (7): 1–8. doi:10.1080/08912963.2018.1546700. S2CID 92754354.
  30. ^ Slimane Zitouni; Christian Laurent; Gareth Dyke; Nour-Eddine Jalil (2019). "An abelisaurid (Dinosauria: Theropoda) ilium from the Upper Cretaceous (Cenomanian) of the Kem Kem beds, Morocco". PLOS ONE. 14 (4): e0214055. Bibcode:2019PLoSO..1414055Z. doi:10.1371/journal.pone.0214055. PMC 6445567. PMID 30939139.
  31. ^ Langer, Max Cardoso; de Oliveira Martins, Neurides; Manzig, Paulo César; de Souza Ferreira, Gabriel; de Almeida Marsola, Júlio César; Fortes, Edison; Lima, Rosana; Sant’ana, Lucas Cesar Frediani; da Silva Vidal, Luciano; da Silva Lorençato, Rosangela Honório; Ezcurra, Martín Daniel Ezcurra (2019). "A new desert-dwelling dinosaur (Theropoda, Noasaurinae) from the Cretaceous of south Brazil". Scientific Reports. 9 (1): 9379. Bibcode:2019NatSR...9.9379L. doi:10.1038/s41598-019-45306-9. PMC 6594977. PMID 31243312.
  32. ^ Cerroni, M.A.; Motta, M.J.; Agnolín, F.L.; Aranciaga Rolando, A.M.; Brissón Egli, F.; Novas, F.E. (2020). "A new abelisaurid from the Huincul Formation (Cenomanian-Turonian; Upper Cretaceous) of Río Negro province, Argentina". Journal of South American Earth Sciences. 98: 102445. Bibcode:2020JSAES..9802445C. doi:10.1016/j.jsames.2019.102445. S2CID 213781725.

References

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