Mystery Solved Paleontology

True nature of ‘Tully monster’ revealed

Ancient oddity is a lamprey ancestor

illustration of a tully monster

IDENTITY CRISIS  An ancient oddball animal that defied identification for decades may be an ancestor of lampreys. 

Paul Mayer/Field Museum of Natural History

By Meghan Rosen

- More than 2 years ago

If some of the most bizarre zoo animals merged into one cartoonish creature, it might look something like the “Tully monster.”

Fossils of Tullimonstrum gregarium, a soft-bodied animal that lived roughly 300 million years ago in what is now Illinois, feature wide-set eyes like a hammerhead shark, a nose like an elephant, and a mouth that could pass for a crab claw with teeth.