Dispersal and diversity in the earliest North American sauropodomorph dinosaurs, with a description of a new taxon. T. Rowe, et al. Proc. R. Soc. B published online before print October 6, 2010
Sarahsaurus aurifontanalis, lived about 190 million years ago (Early Jurassic Period) and was 14 feet long and weighed about 250 pounds.
Evidence from Sarahsaurus and two other early sauropodomorphs suggests that each migrated into North America at the end of the Triassic Period 200 million years ago in separate waves long after the Triassic extinction, and that no such dinosaurs migrated there before the extinction.
Sarahsaurus had physical traits usually associated with gigantic animals. For example, its thigh bones were long and straight like pillars, yet were not much larger than a human's thigh bones. Sarahsaurus shows that sauropodmorphs started out small and later evolved to a very large size.
Sarahsaurus is named in honor of Sarah (Mrs. Ernest) Butler, an Austin philanthropist and long time supporter of the arts and sciences. Butler chaired a fundraising committee for the Dino Pit, an interactive exhibit Rowe helped create at the Austin Nature and Science Center that encourages children to dig up their own fossil replicas.
"I told her if she really raised a million dollars to build the Dino Pit, I'd name a dinosaur after her," he said. link