PITTSBURGH – The mysterious and completely strange-looking Tully monster finally has been identified as an ancient aquatic vertebrate similar to the modern-day lamprey.
A Yale University study was published in Nature and details the team's fossil analysis of the creature that lived more than 300 million years ago. Its crazy features seemed to straddle five major animal families, or phyla, perplexing paleontologists ever since its fossils were discovered in 1958 in Illinois.
The public loves a good monster mystery, explaining the Tully monster's emergence as Illinois' state fossil and why its image graces U-Haul trucks.
"All the features were unusual, especially when they are all together," said Victoria McCoy, the study's lead author, and a postdoctoral fellow at the University of Leicester in England. The foot-long torpedo-shaped animal has eyes on a rigid, horizontal bar across its body and a long proboscis much like an elephant trunk that ends with a mouth bearing tiny teeth. Its features have led to comparisons with crabs, scorpions, insects, worms, other mollusks and lampreys.
But the team first determined that a lightly shaded area in the fossils, which initially was thought to be the gut, actually represented a notochord or backbone. That clearly made it a vertebrate. Then the Tully monster's other features — gill pouches, tail fin and eyes — fell into place as features similar to aquatic vertebrates including the lamprey.
