Open Paleo

Genusaurus

Accarie et al., 1995 JEN-yuu-SOR-uhs /ˌdʒɛnjʊˈsɔːrəs/

Knee lizard; from Latin genu (knee) and Greek sauros (lizard), referring to distinctive features of the knee region

113.2–100.5 million years ago Albian, Early Cretaceous
Early Cretaceous stages

Genusaurus is a genus of abelisaurid theropod from the Early Cretaceous. Its fossils were found in France. Genusaurus is believed to have lived during the Albian stage, around 112-100 million years ago.

Under dispute

The placement of Genusaurus is contentious. It has been assigned to Coelophysoidea originally, then to Noasauridae (Carrano and Sampson, 2008), and to Abelisauridae by most subsequent analyses (Tortosa and colleagues, 2014; Rauhut and Carrano, 2016); it is often unstable, and Pol and colleagues (2024) could not place it, pruning it from their consensus as an unstable taxon. Buffetaut (2026) revised the type material and argued it is an early member of the abelisaurid clade Furileusauria, the earliest known, though it may prove an indeterminate furileusaurian.

Diagnosis

  1. Hatchet-shaped cnemial crest of the tibia, expanded both proximally and distally (now regarded as a character of Furileusauria rather than an autapomorphy of the genus).
  2. Pubic bar extremely oblique towards the front.
  3. Deep lateral sulcus on the tibia at the base of the tibio-fibular crest.
  4. Deep sulcus on the medial surface of the proximal end of the fibula.

Species

Genusaurus sisteronis Accarie et al., 1995

Type species

Named for Sisteron, the town in France near which the holotype specimen was found, with the Latin suffix '-is' forming a place-name adjective.

Holotype
MNHN, Bev.1 , Muséum national d'Histoire naturelle
Material
Left ilium, incomplete left pubis, left femur, proximal ends of the left tibia and fibula, a tarsal, a sacral centrum with a fused synsacral neural-spine bar, and several probably caudal vertebral centra.
Horizon
Albian, Early Cretaceous , 113.2–100.5 million years ago
Locality
Bevons, Alpes-de-Haute-Provence, France Accarie and colleagues (1995) describe the type stratum as greenish clays and glauconitic sands within an undifferentiated middle Albian marl series and name no formal unit for it. Bevons is the commune where the holotype was found, 4.25 km southwest of Sisteron, the town the species is named for.

References

  1. Accarie, H.; Beaudoin, B.; Dejax, J.; Friès, G.; Michard, J. G.; Taquet, P. (1995). Découverte d'un Dinosaure théropode nouveau (Genusaurus sisteronis n. g., n. sp.) dans l'Albien marin de Sisteron (Alpes de Haute-Provence, France) et extension au Crétacé inférieur de la lignée cératosaurienne [Discovery of a new theropod dinosaur (Genusaurus sisteronis n. g., n. sp.) in the marine Albian of Sisteron (Alpes de Haute-Provence, France) and extension of the ceratosaur lineage into the Lower Cretaceous]. Comptes Rendus de l'Académie des Sciences à Paris, série IIa 320: 327-344. accarie1995a
  2. Buffetaut, E. (2026). Furileusaurian osteological characters in Genusaurus sisteronis Accarie et al., 1995, an abelisaurid dinosaur from the Albian (Lower Cretaceous) of south-eastern France. Carnets Natures 12: 79-88.

    Revision of the type material; interprets Genusaurus as an early member of the abelisaurid clade Furileusauria and reinterprets several elements of the holotype.

    buffetaut2026a
  3. Carrano, M. T.; Sampson, S. D. (2008). The Phylogeny of Ceratosauria (Dinosauria: Theropoda). Journal of Systematic Palaeontology 6(2): 183-236. doi:10.1017/S1477201907002246

    Ceratosaurian phylogeny placed Genusaurus within Noasauridae rather than Coelophysoidea

    carrano2008a
  4. Rauhut, O. W. M.; Carrano, M. T. (2016). The theropod dinosaur Elaphrosaurus bambergi Janensch, 1920, from the Late Jurassic of Tendaguru, Tanzania. Zoological Journal of the Linnean Society 178(3): 546-610. Oxford University Press (OUP). doi:10.1111/zoj.12425

    Included among analyses recovering it as an abelisaurid, revising Elaphrosaurus

    rauhut2016b
  5. Tortosa, T.; Buffetaut, E.; Vialle, N.; Dutour, Y.; Turini, E.; Cheylan, G. (2014). A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications. Annales de Paléontologie 100(1): 63-86. Elsevier BV. doi:10.1016/j.annpal.2013.10.003

    Recovered Genusaurus within Abelisauridae (basal polytomy).

    tortosa2014a
  6. Pol, D.; Baiano, M. A.; Černý, D.; Novas, F. E.; Cerda, I. A.; Pittman, M. (2024). A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria. Cladistics 40(3): 307-356. Wiley. doi:10.1111/cla.12583

    Could not place Genusaurus, pruning it from the consensus as an unstable taxon.

    pol2024a