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

[2] The genus is based on a nearly complete and articulated (with bones still connected to each other) skeleton with a fragmentary and disarticulated skull (holotype, specimen number TMM 43646-2).

[6] Sarahsaurus was a basal (or "primitive") member of the sauropodomorph lineage, which also included the more derived (or "advanced") sauropods – giant four-legged herbivores (plant-eaters) with long necks and tails.

Basal sauropodomorphs such as Sarahsaurus already resemble sauropods in a number of aspects, including the elongated neck and robust build, but are reminiscent of the ancestral dinosaurs in others: Sarahsaurus was bipedal (two-legged), with forelimbs that were much shorter than the hind limbs and equipped with powerful grasping hands.

[7][1] Sarahsaurus was mid-sized for a basal sauropodomorph, with its vertebral column measuring more than 3.1 metres (10 ft) in length.

[1] Paleontologist Gregory Paul, in a 2016 popular book, estimated its length at 4 metres (13 ft) and its body weight at 200 kilograms (440 lb).

In contrast to the later sauropods, the sides of the dorsal vertebrae did not show deep cavities caused by air sacs invading the bone (postcranial skeletal pneumaticity).

The holotype specimen includes the sternum (breastbone) and the clavicle (collarbone), which are rarely found with dinosaur skeletons.

[2] In a cladistic analysis, presented by Apaldetti and colleagues in November 2011, Sarahsaurus was found to be most closely related to Ignavusaurus within Massopoda.

[10] Unaysaurus P. gracilis P. engelhardti P. ingens Riojasaurus Eucnemesaurus Sarahsaurus Ignavusaurus Massospondylus Leyesaurus Adeopapposaurus Coloradisaurus Glacialisaurus Lufengosaurus Jingshanosaurus Yunnanosaurus Seitaad Anchisauria A definitive radiometric dating of the Kayenta Formation has not yet been made, and the available stratigraphic correlation has been based on a combination of radiometric dates from vertebrate fossils, magnetostratigraphy and pollen evidence.

[11] It has been surmised that the Kayenta Formation was deposited during the Sinemurian and Pliensbachian stages of the Early Jurassic period, approximately 199 to 182 million years ago.

During the Early Jurassic, the land that is now the Kayenta Formation experienced rainy summers and dry winters.

By the Middle Jurassic period it was being encroached upon from the north by a sandy dune field that would become the Navajo Sandstone.

[15] Vertebrates present in the Kayenta Formation at the time of Sarahsaurus included hybodont sharks, indeterminate bony fish, lungfish, salamanders, the frog Prosalirus, the caecilian Eocaecilia, the turtle Kayentachelys, a sphenodontian reptile, various lizards, and the pterosaur Rhamphinion.