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Pisanosaurus (Wikimedia Commons)


Pisanosaurus (Greek for "Pisano's lizard"): pronounced pih-SAHN-oh-SORE-us


Woodlands of South America

Historical Period:

Late Triassic (220 million years ago)

Size and Weight:

About 3 feet long and 15 pounds



Distinguishing Characteristics:

Small size; probably long tail


About Pisanosaurus:

Few issues in paleontology are more complicated than when, exactly, the first dinosaurs split off into the two major dinosaur families: ornithischian ("bird-hipped") and saurischian ("lizard-hipped") dinosaurs. What makes Pisanosaurus such an unusual discovery is that it was apparently an ornithischian dinosaur that lived 220 million years ago in South America, at the same time as early theropods like Eoraptor and Herrerasaurus (which would push the ornithischian line to millions of years earlier than had been previously believed). Further complicating matters, Pisanosaurus possessed an ornithischian-style head perched atop a saurischian-style body. Its closest relative seems to have been the southern African Eocursor, which may have pursued an omnivorous diet.

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