Open Paleo

Elaphrosaurinae

Rauhut & Carrano, 2016 Type genus Elaphrosaurus

Its genera lived 165.3–149.2 million years ago Middle Jurassic–Late Jurassic
Middle Jurassic and Late Jurassic stages

Elaphrosaurinae is a subfamily of ceratosaurian theropod dinosaurs, usually classified within the family Noasauridae. Its members were lightly built animals with small skulls, long necks, and long legs, and the group ranges from the Middle Jurassic through the Late Cretaceous. Most of the best-known forms, including Elaphrosaurus and Limusaurus, lived during the Jurassic, while Huinculsaurus extends the group into the Cretaceous. Adults were completely toothless, their jaws instead edged with a horny beak, and evidence from Limusaurus — including preserved gastroliths and chemical signatures — suggests they were largely herbivorous, though juveniles retained teeth and may have been omnivorous or carnivorous. The subfamily is distinguished by cervical vertebrae with strongly concave articular faces and cervical ribs fused to the vertebral bodies, along with unusually small hips set against long legs, the thigh bone measuring more than 1.3 times the length of the ilium.

Under dispute

The position of Elaphrosaurinae within Ceratosauria is unsettled. Rauhut and Carrano (2016) and most reference works place it inside Noasauridae as the sister subclade to Noasaurinae, the arrangement followed, and both analyses of Pol and colleagues (2024) recover it as an early branch of Noasauridae, though their Bayesian tree moves Limusaurus into Noasaurinae. However, one of the three data matrices analyzed by Hendrickx and colleagues (2024) recovered Elaphrosaurinae outside Noasauridae, near the base of Ceratosauria as the sister group of Neoceratosauria, and the position is acknowledged as weakly constrained.

Diagnosis

  1. Extreme transverse constriction of the posterior cervical and anterior dorsal vertebral centra
  2. Elongate, low cervical vertebrae producing a long neck
  3. Reduction or complete loss of the dentition (edentulism in Limusaurus)
  4. Gracile, cursorial hindlimb proportions

Genera placed directly in Elaphrosaurinae

  • Elaphrosaurus Janensch, 1920 Kimmeridgian (154.8–149.2 Ma)Tanzania
  • Limusaurus Xu et al., 2009 Callovian–Oxfordian (165.3–154.8 Ma)China

References

  1. 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

    Placed Elaphrosaurus in Noasauridae and erected the subfamily Elaphrosaurinae.

    rauhut2016b
  2. Hendrickx, C.; Cerroni, M. A.; Agnolín, F. L.; Catalano, S.; Ribeiro, C. F.; Delcourt, R. (2024). Osteology, relationship, and feeding ecology of the theropod dinosaur Noasaurus leali, from the Late Cretaceous of North-Western Argentina. Zoological Journal of the Linnean Society 202(4): zlae150. doi:10.1093/zoolinnean/zlae150

    One matrix placed Elaphrosaurinae outside Noasauridae, as sister to Neoceratosauria.

    hendrickx2024a
  3. 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

    Recovered Elaphrosaurinae as an early branch of Noasauridae in parsimony and Bayesian analyses, the latter with Limusaurus moved into Noasaurinae.

    pol2024a