Clever Like a Pterosaur

Analysis of their skulls show that these dinos weren't pea-brained after all.

By Kathy A. Svitil|Sunday, March 28, 2004

Pterosaurs, the winged reptiles that ruled the skies during the era of the dinosaurs, may not have been the pea-brains that scientists thought. High-tech analyses of pterosaur skulls show that the first flying vertebrates packed some sophisticated navigational hardware.

Larry Witmer, a paleontologist at Ohio University in Athens, and his colleagues examined two unusually intact pterosaur skulls, one from crow-size Rhamphorhynchus, the other from the eagle-size Anhanguera. The researchers took high-resolution CT scans of the skulls to map the imprint of braincases and then used a computer program to reconstruct the contours of the actual brains. The results reveal that pterosaurs had a giant flocculus, a brain region responsible for keeping track of the body’s location and for coordinating the movement of the eyes.

That oversize flocculus may have collected sensory information from nerve fibers along the creature’s wings, Witmer says. He speculates that the flocculus worked in concert with the semicircular canals of the inner ear—which help determine position and orientation—to stabilize the creature’s gaze as it turned its head. In Anhanguera the main canal would have been horizontal when the pterosaur’s head was tipped 30 degrees below horizontal, a position ideal for spotting prey on the ground. “We used to think that pterosaurs were kind of lame, but this shows they had the neural machinery to be capable fliers,” Witmer says.
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