Open Paleo

Caseosaurus

Hunt et al., 1998 KAY-zee-oh-SOR-uhs /ˌkeɪzioʊˈsɔːrəs/ Disputed

Named after Ermine Cowles Case, the scientist who discovered it, combined with Greek sauros meaning 'lizard'. Full meaning: 'Case's lizard'.

237.0–205.7 million years ago Carnian–Norian, Late Triassic
Late Triassic stages

Caseosaurus is a genus of saurischian dinosaur that lived approximately 221.5 to 212 million years ago during the latter part of the Triassic Period in what is now Texas, North America. It was a small, lightly-built, bipedal, ground-dwelling carnivore, and could grow up to 2 m (6.6 ft) long.

Under dispute

Caseosaurus crosbyensis was revalidated as a herrerasaurian with an emended diagnosis by Baron and Williams (2018), who could not resolve its position within Herrerasauria; it is regarded by some workers as a nomen dubium.

Diagnosis

  1. Ilium with an elongate and dorsoventrally narrow posterior blade
  2. Narrow ridge on the lateral margin extending from the anterodorsal margin of the acetabulum to the anterodorsal anterior spine
  3. Highly reduced brevis fossa
  4. Semicircular margin dorsal to the acetabulum

Species

Caseosaurus crosbyensis Hunt et al., 1998 Disputed

Type species

A Latinized rendering of Crosby County in Texas, the site of the holotype's discovery.

Holotype
UMMP 8870 , Museum of Paleontology, University of Michigan
Material
Isolated hip bone (ilium), ~141 mm
Horizon
Tecovas Formation, Carnian–Norian, Late Triassic , 237.0–205.7 million years ago
Locality
Texas, United States

References

  1. Hunt, A. P.; Lucas, S. G.; Heckert, A. B.; Sullivan, R. M.; Lockley, M. G. (1998). Late Triassic dinosaurs from the western United States. Geobios 31(4): 511-531. Elsevier BV. doi:10.1016/s0016-6995(98)80123-x hunt1998a
  2. Baron, M. G.; Williams, M. E. (2018). A re-evaluation of the enigmatic dinosauriform Caseosaurus crosbyensis from the Late Triassic of Texas, USA and its implications for early dinosaur evolution. Acta Palaeontologica Polonica 63(1): 129-145. Polish Academy of Sciences. doi:10.4202/app.00372.2017

    Re-evaluated Caseosaurus as a herrerasaurian with an emended diagnosis.

    baron2018c
  3. Marsh, A. D.; Parker, W. G.; Langer, M. C.; Nesbitt, S. J. (2019). Redescription of the holotype specimen of Chindesaurus bryansmalli Long and Murry, 1995 (Dinosauria, Theropoda), from Petrified Forest National Park, Arizona. Journal of Vertebrate Paleontology 39(3): e1645682. doi:10.1080/02724634.2019.1645682

    Treats Caseosaurus crosbyensis as a nomen dubium, following the apomorphy-based identification of its holotype to Dinosauriformes.

    marsh2019a
  4. Novas, F. E.; Agnolín, F. L.; Ezcurra, M. D.; Müller, R. T.; Martinelli, A. G.; Langer, M. C. (2021). Review of the fossil record of early dinosaurs from South America, and its phylogenetic implications. Journal of South American Earth Sciences 110: 103341. doi:10.1016/j.jsames.2021.103341

    Follows the nomen dubium reading while accepting herrerasaur affinity for the material.

    novas2021a