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// Workers AI · dad joke modeWhat did the Anteosauria say? Dino-mite ancestors.

From Wikipedia, the free encyclopedia
(Redirected from Anteosaur)
Anteosaurs
Temporal range: Middle Permian, 270–260 Ma
Life restoration of Anteosaurus
Skeleton of Titanophoneus
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Suborder: †Dinocephalia
Infraorder: †Anteosauria
Boonstra, 1962
Family: †Anteosauridae
Boonstra, 1954
Subgroups
Synonyms
  • Anteosauroidea King, 1988

Anteosauria is a clade of large, basal carnivorous dinocephalian therapsids characterized by large canines and incisors, as well as short limbs. Anteosaurs are known from the Middle Permian formations of South Africa, Russia, China, and Brazil. Some grew very large, with skulls 50–80 centimetres (20–31 in) long, and were the largest predators of their time. Anteosaurs, as well as the rest of the dinocephalians, went extinct during the Capitanian mass extinction, which marked the end of the Middle Permian.[3][4]

Description

[edit]
Size of Anteosaurus compared to a human
Size of Titanophoneus compared to a human
Skeleton of Titanophoneus
Skull diagram of Syodon

Anteosaurs are unified by several characters, including having upturned premaxillas (the tooth bearing bone at the front of the snout), the vomer bones on the palate having raised, elongate edges, a "jugal-lacrimal ridge", the quadrate rami of the pterygoid bones are "tightly adpressed", the ventral (lower) border of the maxilla (the main tooth bearing upper jaw bone) is convex, and having a postorbital bar that is strongly anteroventrally (towards both the front and bottom of the skull) curved.[5] There are generally 4-5 pairs of incisors and pair of canines in the upper and lower jaws, with the incisor teeth like those of other dinocephalians being interlocking. The canine teeth in the upper jaw are particularly enlarged. The number of postcanine teeth varies from 8-11 in both jaws. The post-canine teeth are generally blunt/bulbous.[6][5][7]41-45, 57 The tails of anteosaurs are relatively long, with some having over 60 caudal vetebrae.[7]46 Anteosaurs vary considerably in size, with adult skulls varying in length from 21.8 centimetres (8.6 in) in Syodon to over 80 centimetres (31 in) in Anteosaurus,[8] with Anteosaurus estimated to exceed 400 kilograms (880 lb) in body mass.[9] Adults of large anteosaur species can exhibit considerable thickening (pachyostosis) of the bones of the skull roof, though this is relatively incipient in some anteosaurs.[10]

Classification

[edit]

Evolutionary relationships

[edit]

Initially, it has been suggested that the estemmenosuchids are the most basal of the dinocephalians.[11][12] However, most experts now recover anteosaurs as the most basal of the dinocephalians.[13][14][5] It has been hypothesized that the Russian anteosaurs Archaeosyodon and Microsyodon generally considered the most basal members of the clade,[13][15] although several recent studies have now recovered Sinophoneus as the most basal anteosaur.[1][16] They have featured in common with pelycosaurs (Carroll 1988) and biarmosuchians (Chudinov 1965), and, with the tapinocephalians, are part of the first major evolutionary radiation of the therapsids.[13]

Phylogeny

[edit]

James Hopson and Herbert Barghusen in 1986 provided the first cladistic study of the Therapsida. They used the term "Anteosauria" and synonymised the families Brithopodidae and Anteosauridae. In 2010, Christian Kammerer published a re-evaluation of anteosaurian relationships.[5]

The cladogram below follows an updated (2012) version of Kammerer's analysis by Juan Carolos Cisneros and colleagues.[17]

Cladogram following Liu (2013).[1]

Taxonomy

[edit]

The group name Anteosauria was first used by L. D. Boonstra in 1955 to include the families Brithopodidae and Anteosauridae.[18] In his 1988 review, Gillian King named the superfamily Anteosauroidea to include the following families, in which the "Titanosuchidae" is equivalent to the "Tapinocephalia".[19]

  • Superfamily Anteosauroidea Boonstra, 1962
    • Family Brithopidae Boonstra, 1972
      • Subfamily Brithopodinae Efremov, 1954
      • Subfamily Anteosaurinae Boonstra, 1954
    • Family Titanosuchidae Boonstra, 1972
      • Subfamily Titanosuchinae Broom, 1903
      • Subfamily Tapinocephalinae Lydekker, 1890

However, Kammerer (2011) found the postcranial of Brithopus to be different from anteosaurs, as the distal humeral had an relatively large entepicondylar foramen and well-developed supinator process, in comparison anteosaurs had a relatively small entepicondylar foramen supinator process. This suggests Brithopus was an tapinocephalian instead of an anteosaur. Within the same paper, he also recovers Deuterosaurus as an tapinocephalian. His analysis recovers anteosaurs as a monophyletic clade of dinocephalians and was equivalent to Anteosauridae.[5] Following Kammerer (2011), other experts have recovered anteosaurids as equivalent to Anteosauria.[1][16][17]

However, Duhamel et al. (2026) found little evidence of recovering anteosaurs as a monophyletic group and recovered Sinophoneus outside of the clade as the vomers of Sinophoneus lacked elongated edges, as well as the absence of a ridge between the jugal and lacrimal.[20]

Palaeobiology

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Ecology

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Life restoration of Anteosaurus
Two Archaeosyodon feeding on an Estemmenosuchus

The stance of a typical anteosaur, such as Titanophoneus, was primitive. Rather than the limbs being drawn in under the body, the stance was more sprawling. Olson (1962) notes that the Russian dinocephalian assemblages indicate environments tied to water, and Boonstra considered that the roughly contemporary Anteosaurus was a slinking crocodile-like semi-aquatic form. The long tail, weak limbs, and sprawling posture do indeed suggest some sort of crocodile-like existence. However, the thickened skull-roof indicates that these animals were quite able to get about on land, if they were to practice the typically dinocephalian head-butting behavior. All other head-butters, pachycephalosaurian dinosaurs, titanothere ungulates, and goats were or are completely terrestrial. Bhat et al. (2021) suggested that Anteosaurus may have occasionally inhabited shallow and short-lived pools, similar to modern day hippopotamus, based on its bone histology.[15]

On the other hand, analysis on the brain of a juvenile specimen suggested Anteosaurus were not sluggish predators. X-ray imaging and 3-D reconstructions showcase that Anteosaurus were fast, agile animals in spite of their great size: the inner ears were larger than those of its closest relatives and competitors, suggesting that Anteosaurus was well-suited to the role of an apex predator that could outrun both its rivals and prey alike. The area of its brain responsible for coordinating the movements of the eyes with the head was also determined to have been exceptionally large, an important feature to ensure that they could track their prey accurately. As a result, Anteosaurus is thought to be well-adapted to pursuing land-based prey.[21]

Feeding

[edit]

Anteosaurs were evolved to prey on particularly large animals and were among the most highly predaceous of all synapsids (Sennikov, 1996), potential prey included the bull-sized armored pareiasaurs (Lee, 1997) and enormous tapinocephalid dinocephalians (Rubidge, 1995).[22]

The large anteosaurs were efficient predators, more specialized than earlier and more primitive biarmosuchid and eotitanosuchid carnivorous therapsids, as the temporal opening behind the eye socket was larger, indicating a greater muscle mass available for closing the lower jaw. Large pterygoid flanges indicate a well-developed Kinetic-Inertial system in anteosaurs, and increased vertical alignment of the temporalis muscles suggests an expanded Static-Pressure component of the bite cycle.[22]

Social behaviour

[edit]

Anteosaurs likely used their large canines, in addition to their primary predatory function, as social display items, and likely engaged in face biting combat against rival individuals of the same species.[21]

References

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  1. 1 2 3 4 Liu, J. (2013). "Osteology, Ontogeny, and Phylogenetic Position of Sinophoneus yumenensis (Therapsida, Dinocephalia) from the Middle Permian Dashankou Fauna of China". Journal of Vertebrate Paleontology. 33 (6): 1394–1407. Bibcode:2013JVPal..33.1394L. doi:10.1080/02724634.2013.781505. S2CID 85577626.
  2. ↑ Costa Santos, Mateus A.; Paes Neto, Voltaire D.; Schultz, Cesar L.; Cisneros, Juan; Pierce, Stephanie E.; Pinheiro, Felipe L. (10 September 2023). "Cranial osteology of the Brazilian dinocephalian Pampaphoneus biccai (Anteosauridae: Syodontinae)". Zoological Journal of the Linnean Society. 199 (4): 1034–1058. doi:10.1093/zoolinnean/zlad071. ISSN 0024-4082. Retrieved 21 February 2025 – via Oxford Academic.
  3. ↑ Day, M. O.; Rubidge, Bruce S. (2021). "The Late Capitanian Mass Extinction of Terrestrial Vertebrates in the Karoo Basin of South Africa". Frontiers in Earth Science. 9 631198: 15. Bibcode:2021FrEaS...9...15D. doi:10.3389/feart.2021.631198.
  4. ↑ Retallack, G. J., Metzger, C. A., Greaver, T., Jahren, A. H., Smith, R. M. H. & Sheldon, N. D. (2006). "Middle-Late Permian mass extinction on land". Geological Society of America Bulletin 118 (11-12): 1398-1411.
  5. 1 2 3 4 5 Kammerer, Christian F. (2011). "Systematics of the Anteosauria (Therapsida: Dinocephalia)". Journal of Systematic Palaeontology. 9 (2). doi:10.1080/14772019.2010.492645.
  6. ↑ Benoit, J.; Kruger, A.; Jirah, S.; Fernandez, V.; Rubidge, Bruce S. (2021). "Palaeoneurology and palaeobiology of the dinocephalian therapsid Anteosaurus magnificus" (PDF). Acta Palaeontologica Polonica. 66. doi:10.4202/app.00800.2020. Archived (PDF) from the original on 3 July 2022. Retrieved 25 October 2022.
  7. 1 2 KING, G.M. 1988. Anomodontia. In: Wellnhofer, P. (ed.), Encyclopedia of Paleoherpetology. 174 pp. Stuttgart, Gustav Fischer.
  8. ↑ Kruger, Ashley; Rubidge, Bruce S.; Abdala, Fernando (2018-01-26). "A juvenile specimen of Anteosaurus magnificus Watson, 1921 (Therapsida: Dinocephalia) from the South African Karoo, and its implications for understanding dinocephalian ontogeny". Journal of Systematic Palaeontology. 16 (2): 139–158. doi:10.1080/14772019.2016.1276106. hdl:11336/67088. ISSN 1477-2019.
  9. ↑ Benoit, Julien; Midzuk, Adam J. (August 2024). "Estimating the endocranial volume and body mass of Anteosaurus, Jonkeria, and Moschops (Dinocephalia, Therapsida) using 3D sculpting". Palaeontologia Electronica. doi:10.26879/1377. Archived from the original on 8 November 2025. Retrieved 19 September 2025.
  10. ↑ Kruger, Ashley; Rubidge, Bruce S.; Abdala, Fernando (2018-01-26). "A juvenile specimen of Anteosaurus magnificus Watson, 1921 (Therapsida: Dinocephalia) from the South African Karoo, and its implications for understanding dinocephalian ontogeny". Journal of Systematic Palaeontology. 16 (2): 139–158. doi:10.1080/14772019.2016.1276106. hdl:11336/67088. ISSN 1477-2019.
  11. ↑ Kemp, T. S. (1982). Mammal-like Reptiles and the Origin of Mammals. New York: Academic Press. pp. 363pp.
  12. ↑ King, G. M. (1988). "Anomodontia". Encyclopedia of Paleoherpetology. Vol. Part 17 C. Stuttgart and New York: Gutsav Fischer Verlag.
  13. 1 2 3 Rubidge, Bruce S.; Sidor, Christian A. (2001). "Evolutionary Patterns Among Permo-Triassic Therapsids". Annual Review of Ecology and Systematics. 32: 449–480.
  14. ↑ Bhat, M. S.; Shelton, C.; Chinsamy-Turan, A. (2021). "Bone histology of dinocephalians (Therapsida, Dinocephalia): palaeobiological and palaeoecological inferences". Papers in Palaeontology. 8. doi:10.1002/spp2.1411.
  15. 1 2 Bhat, M. S.; Shelton, C. D.; Chinsamy, A. (2021). "Inter-element variation in the bone histology of Anteosaurus (Dinocephalia, Anteosauridae) from the Tapinocephalus Assemblage Zone of the Karoo Basin of South Africa". PeerJ. 9 e12082. doi:10.7717/peerj.12082. PMC 8434808. PMID 34589298.
  16. 1 2 Costa Santos, Mateus A.; Paes Neto, Voltaire D.; Schultz, Cesar L.; Cisneros, Juan; Pierce, Stephanie E.; Pinheiro, Felipe L. (10 September 2023). "Cranial osteology of the Brazilian dinocephalian Pampaphoneus biccai (Anteosauridae: Syodontinae)". Zoological Journal of the Linnean Society. 199 (4): 1034–1058. doi:10.1093/zoolinnean/zlad071. ISSN 0024-4082. Retrieved 21 February 2025 – via Oxford Academic.
  17. 1 2 Cisneros, J.C., Fernando Abdala, Saniye Atayman-Güven, Bruce S. Rubidge, A. M. Celâl Şengör, and Cesar L. Schultz. (2012). Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea. PNAS, 109 (5): 1584-1588. doi:10.1073/pnas.1115975109
  18. ↑ Boonstra, L.D. (1955). "The girdles and limbs of the South African Deinocephalia". Annals of the South African Museum. 42: 185–326.
  19. ↑ King, G.M. (1988). "Anomodontia". Handbuch der Palaoherpetologie. 17 C. Stuttgart: Gustav Fischer Verlag.
  20. ↑ Duhamel, Alienor; Wynd, Brenen; Wright, April Marie; Moopen, Atashni; Benoit, Julien; Rubidge, Bruce (2026-03-11). "Rethinking therapsid phylogeny through Bayesian and cladistic approaches". Scientific Reports. 16 (1). doi:10.1038/s41598-026-38195-2. ISSN 2045-2322. PMC 13103076. PMID 41813723.
  21. 1 2 Benoit, J.; Kruger, A.; Jirah, S.; Fernandez, V.; Rubidge, Bruce S. (2021). "Palaeoneurology and palaeobiology of the dinocephalian therapsid Anteosaurus magnificus" (PDF). Acta Palaeontologica Polonica. 66. doi:10.4202/app.00800.2020.
  22. 1 2 "Evolutionary Patterns In The History of Permo-Triassic Synapsid Predators And Cenozoic Synapsid Predators" (PDF). Blaire Van Valkenburgh and Ian Jenkins. Archived from the original (PDF) on 17 October 2013. Retrieved 16 October 2013.

Further reading

[edit]
  • Boonstra, L.D., 1972, Discard the names Theriodontia and Anomodontia: a new classification of the Therapsida. Annals of the South African Museum 59:315-338.
  • Carroll, R. L., 1988, Vertebrate Paleontology and Evolution, WH Freeman & Co.
  • Chudinov, P. K. 1965, "New Facts about the Fauna of the Upper Permian of the USSR", Journal of Geology, 73:117-30
  • Hopson, J.A. and Barghusen, H.R., 1986, An analysis of therapsid relationships in N Hotton III, PD MacLean, JJ Roth and EC Roth, The Ecology and Biology of Mammal-like Reptiles, Smithsonian Institution Press, pp. 83–106
  • King, G.M., 1988, "Anomodontia" Part 17 C, Encyclopedia of Paleoherpetology, Gutsav Fischer Verlag, Stuttgart and New York,
  • Rubidge, B.S. & Sidor, C.A. 2001, Evolutionary patterns among Permo-Triassic therapsids. Annu. Rev. Ecol. Syst. 32: 449-480.
[edit]
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