Anchisaurus. Nobu Tamura


Anchisaurus (Greek for "near lizard"); pronounced ANN-kih-SORE-us


Woodlands of eastern North America

Historical Period:

Early Jurassic (190 million years ago)

Size and Weight:

About six feet long and 75 pounds



Distinguishing Characteristics:

Long, slim body; ridged teeth for shredding leaves

About Anchisaurus

Anchisaurus is one of those dinosaurs that was discovered ahead of its time. When this small plant-eater was first excavated (from a well in East Windsor, Connecticut, of all places) in 1818, no one knew quite what to make of it; the bones were initially identified as belonging to a human, until the discovery of a nearby tail put an and to that idea! It was only decades later, in 1885, that the famous American paleontologist Othniel C. Marsh conclusively identified Anchisaurus as a dinosaur, though its exact classification couldn't be pinned down until more was known in general about these long-extinct reptiles. And Anchisaurus was certainly strange compared to most dinosaurs discovered up to that time, a human-sized reptile with grasping hands, a bipedal posture, and a swollen belly populated by gastroliths (swallowed stones that aided in the digestion of tough vegetable matter).

Today, most paleontologists consider Anchisaurus to have been a prosauropod, the family of svelte, occasionally bipedal plant-eaters of the late Triassic and early Jurassic periods that were distantly ancestral to the giant sauropods, like Brachiosaurus and Apatosaurus, that roamed the earth during the later Mesozoic Era. However, it's also possible that Anchisaurus represented some kind of transitional form (a so-called "basal sauropodomorph"), or that prosauropods as a whole were omnivorous, since there's (inconclusive) evidence, based on the shape and arrangement of its teeth, that this dinosaur may occasionally have supplemented its diet with meat.

Like many dinosaurs discovered in the early 19th century, Anchisaurus has gone through its fair share of name changes. The fossil specimen was originally named Megadactylus ("giant finger") by Edward Hitchcock, then Amphisaurus by Othniel C. Marsh, until he discovered that this name was already "preoccupied" by another animal genus and settled instead on Anchisaurus ("near lizard"). Further complicating matters, the dinosaur we know as Ammosaurus may actually have been a species of Anchisaurus, and both of these names are probably synonymous with the now-discarded Yaleosaurus, named after Marsh's alma mater. Finally, a sauropodomorph dinosaur discovered in South Africa in the early 19th century, Gyposaurus, may yet wind up being assigned to the Anchisaurus genus.

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Your Citation
Strauss, Bob. "Anchisaurus." ThoughtCo, Aug. 25, 2020, Strauss, Bob. (2020, August 25). Anchisaurus. Retrieved from Strauss, Bob. "Anchisaurus." ThoughtCo. (accessed March 27, 2023).