Open Paleo

Sarahsaurus

Rowe et al., 2011 SAH-ruh-SOR-us

Named in honor of Sarah (Mrs. Ernest) Butler, an Austin philanthropist who helped fund the 'Dino Pit' exhibit at the Austin Nature and Science Center, combined with Greek 'sauros' meaning 'lizard'.

199.5–184.2 million years ago Sinemurian–Pliensbachian, Early Jurassic
Early Jurassic stages

Sarahsaurus is a genus of basal sauropodomorph dinosaur which lived during the Early Jurassic period in what is now northeastern Arizona, United States.

Under dispute

Sarahsaurus aurifontanalis was recovered by its describers as a basal sauropodomorph well outside Massospondylidae (Rowe and colleagues, 2011), and just outside Massospondylidae by Apaldetti and colleagues (2011), but within Massospondylidae, as the sister of Ignavusaurus, by Chapelle and colleagues (2019).

Diagnosis

  1. Low wall between basicranial tubera with central anterior fossa
  2. Spine tables on dorsal vertebrae
  3. Manual phalangeal formula of 2-3-4-2-2
  4. Presence of pubic foramen

Species

Sarahsaurus aurifontanalis Rowe et al., 2011

Type species

From Latin 'aurum' meaning 'gold' and 'fontanalis' meaning 'of the spring', referring to Gold Spring, Arizona, where the holotype was discovered.

Holotype
TMM 43646-2 , Texas Memorial Museum, Austin, Texas, USA (used for collections now housed in the Vertebrate Paleontology Collections at the Jackson School Museum of Earth History, Austin, Texas, USA), now called the Texas Science and Natural History Museum
Material
Partial skull (premaxilla, frontal, quadrate, braincase) and nearly complete postcranial skeleton.
Horizon
Kayenta Formation, Sinemurian–Pliensbachian, Early Jurassic , 199.5–184.2 million years ago
Locality
Dilophosaurus Quarry, Arizona, United States

Notable specimens

  • MCZ 8893

    Museum of Comparative Zoology, Harvard University complementary

    Referred nearly complete skull, originally identified as Massospondylus sp., that supplies cranial anatomy missing from the holotype, whose skull is fragmentary and disarticulated. Its open braincase sutures mark a less mature individual than the mature holotype.

    Rowe et al. (2011)Attridge et al. (1985)

References

  1. Attridge, J.; Crompton, A. W.; Jenkins, F. A., Jr. (1985). The southern Liassic prosauropod Massospondylus discovered in North America. Journal of Vertebrate Paleontology 5(2): 128-132. doi:10.1080/02724634.1985.10011850 attridge1985a
  2. Rowe, T. B.; Sues, H. D.; Reisz, R. R. (2011). Dispersal and diversity in the earliest North American sauropodomorph dinosaurs, with a description of a new taxon. Proceedings of the Royal Society B: Biological Sciences 278(1708): 1044-1053. The Royal Society. doi:10.1098/rspb.2010.1867 rowe2011a
  3. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the appearance features.

    paul2024a
  4. Apaldetti, C.; Martínez, R. N.; Alcober, O. A.; Pol, D. (2011). A New Basal Sauropodomorph (Dinosauria: Saurischia) from Quebrada del Barro Formation (Marayes-El Carrizal Basin), Northwestern Argentina. PLoS ONE 6(11): e26964. Public Library of Science (PLoS). doi:10.1371/journal.pone.0026964

    Recovered Sarahsaurus just outside Massospondylidae as a basal massopodan.

    apaldetti2011a
  5. Chapelle, K. E. J.; Barrett, P. M.; Botha, J.; Choiniere, J. N. (2019). Ngwevu intloko: a new early sauropodomorph dinosaur from the Lower Jurassic Elliot Formation of South Africa and comments on cranial ontogeny in Massospondylus carinatus. PeerJ 7: e7240. PeerJ. doi:10.7717/peerj.7240

    Recovered Sarahsaurus within Massospondylidae.

    chapelle2019a
  6. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Leaves Sarahsaurus unresolved between Massospondylidae and its outgroups.

    jones2026b