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Majungasaurus

Lavocat, 1955 mah-joon-gah-sore-us /məˌdʒʌŋɡəˈsɔːrəs/

Named after Mahajanga (formerly Majunga), a city and region in northwestern Madagascar where it was discovered, combined with Greek 'sauros' (lizard); meaning 'Mahajanga lizard'

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

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.

Diagnosis

  1. Dorsoventrally deep, fused nasals that are strongly pneumatized via large, bilateral foramina
  2. Nasal processes of left and right premaxillae separated by a thin lamina of nasal
  3. Maxilla bearing 17 alveoli
  4. Frontals rounded rostrally rather than forming a double notch
  5. Frontals with a sculptured, median cornual process in adults that is variably pneumatic
  6. Pronounced median fossa on the sagittal (frontoparietal) crest
  7. Dentary bearing 17 alveoli, with virtually no extension caudal to the last alveolus and a ventral position of the lateral sulcus
  8. Teeth bearing weakly developed interdenticular sulci
  9. Long, falciform atlantal epipophysis
  10. Vertebral centra in the cranial dorsal series with dorsoventrally elongate articular surfaces
  11. Cranial and caudal borders of the midcervical transverse processes parallel in lateral view
  12. Dorsal and caudal vertebral neural spines dorsally expanded, both transversely and craniocaudally
  13. Cervical ribs pneumatized via multiple, enlarged foramina on the medial surface of the shaft, and accessory foramina on the cranial and caudal surfaces of the capitulotubercular web

Species

Majungasaurus crenatissimus (Depéret, 1896)

Type species

First named as Megalosaurus crenatissimus

From Latin 'crenatus' meaning 'notched' combined with the superlative suffix '-issimus' meaning 'most', referring to the numerous serrations on both the front and rear edges of the teeth.

Neotype
MNHN.MAJ 1 , Muséum national d'Histoire naturelle
Material
Fragmentary right dentary of a subadult individual.
Horizon
Maevarano Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Ravine north of Berivotra, Mahajanga, Madagascar

Synonyms

  • Dryptosaurus crenatissimus reassigned

    Depéret and Savornin (1928) moved the species to Dryptosaurus; Lavocat (1955) later erected Majungasaurus for it.

  • Megalosaurus crenatissimus reassigned

    The original combination; Depéret (1896) named the species on a syntype series that was later judged non-diagnostic.

Synonyms of the genus

Name Type Reason
Majungatholus junior subjective Initially erected as a separate genus due to the lack of overlapping material; subsequently recognized as referable to Majungasaurus.

Notable specimens

  • FMNH PR 2100

    Field Museum of Natural History Found 1996 exceptional preservation

    A spectacularly complete skull preserving cranial anatomy absent from the fragmentary type dentary. Its dome-shaped frontal swelling matched Majungatholus, leading to that name's recognition as a synonym, and CT scanning reconstructed its brain and inner ear.

    Sampson (1998)Sampson & Witmer (2007)

  • UA 8678

    Universite d’Antananarivo physiology

    A superbly preserved series of vertebrae and ribs whose pneumatic foramina let scientists reconstruct the respiratory system, implying avian-style air sacs and flow-through ventilation, with implications for the early evolution of bird respiration.

    O'Connor & Claessens (2005)

ICZN cases

  • Type specimen Ruled

    Opinion 2269 set aside all previous type fixations for Megalosaurus crenatissimus under the plenary power and designated MNHN.MAJ 1, the right dentary Depéret described, as the neotype, the original material being non-diagnostic. Majungasaurus was placed on the Official List of Generic Names and crenatissimus on the Official List of Specific Names.

    Application: Carrano et al. (2009) Opinion: International Commission on Zoological Nomenclature (2011)

References

  1. Lavocat, R. (1955). Sur une portion de mandibule de théropode provenant du Crétacé supérieur de Madagascar [On a portion of theropod mandible from the Upper Cretaceous of Madagascar]. Bulletin du Muséum National d'Histoire Naturelle, Paris, 2e série 27(3): 256-259. lavocat1955a
  2. Carrano, M. T.; Krause, D. W.; O'Connor, P. M.; Sampson, S. D. (2009). Case 3487. Megalosaurus crenatissimus Depéret, 1896 (currently Majungasaurus crenatissimus; Dinosauria, Theropoda): proposed replacement of the holotype by a neotype. Bulletin of Zoological Nomenclature 66(3): 261-264. International Trust for Zoological Nomenclature.

    Petitioned the Commission to replace the non-diagnostic holotype with a neotype.

    carrano2009a
  3. International Commission on Zoological Nomenclature (2011). Opinion 2269 (Case 3487). Megalosaurus crenatissimus Depéret, 1896 (currently Majungasaurus crenatissimus; Dinosauria, Theropoda): designation of a neotype. Bulletin of Zoological Nomenclature 68(1): 89-90. International Trust for Zoological Nomenclature. doi:10.21805/bzn.v68i1.a7

    Opinion 2269, which granted the petition and fixed MNHN.MAJ 1 as the neotype.

    iczn2011a
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c
  5. Sampson, S. D. (1998). Predatory dinosaur remains from Madagascar: implications for the Cretaceous biogeography of Gondwana. Science 280(5366): 1048-1051. doi:10.1126/science.280.5366.1048 sampson1998a
  6. Krause, D. W.; Sampson, S. D.; Carrano, M. T.; O'Connor, P. M. (2007). Overview of the history of discovery, taxonomy, phylogeny, and biogeography of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology 27. doi:10.1671/0272-4634(2007)27[1:OOTHOD]2.0.CO;2

    Opening chapter of Memoir 8, carrying the systematics and the revised diagnosis the other chapters defer to.

    krause2007a
  7. Sampson, S. D.; Witmer, L. M. (2007). Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology 27: 32-102. doi:10.1671/0272-4634(2007)27[32:CAOMCT]2.0.CO;2

    Society of Vertebrate Paleontology Memoir 8.

    sampson2007a
  8. O'Connor, P. M.; Claessens, L. P. A. M. (2005). Basic avian pulmonary design and flow-through ventilation in non-avian theropod dinosaurs. Nature 436(7048): 253-256. doi:10.1038/nature03716 o'connor2005a
  9. Depéret, C. (1896). Note sur les dinosauriens sauropodes et théropodes du Crétacé supérieur de Madagascar [Note on the sauropod and theropod dinosaurs from the Upper Cretaceous of Madagascar]. Bulletin de la Société Géologique de France 24: 176-194. depéret1896a
  10. Depéret, C.; Savornin, J. (1928). La faune de reptiles et de poissons albiens de Timimoun (Sahara algérien) [The Albian reptile and fish fauna of Timimoun (Algerian Sahara)]. Bulletin de la Société Géologique de France 27: 257-265. depéret1928a