Field Museum Scientists Reveal Tully Monster’s True Nature


The video cannot be displayed.

Nearly 60 years ago, an amateur fossil collector named Francis Tully stumbled upon an incredibly peculiar fossil. The odd jumble of physical attributes – a tube-shaped body, eyes on stalks, and a long, skinny snout with a claw or jaw at the end – looked like they would be more at home in a Dr. Seuss book than in the swamps of Illinois.

Paleontologists were flummoxed. Was it a mollusk? An arthropod? A worm? Or none of the above? Thanks to a yearlong Field Museum collaboration with Yale University scientists and other institutions, the Tully monster's true nature has finally been revealed—and it’s a vertebrate! 

Thanks to our sponsors:

View all sponsors

[Illinois ‘Monster’ Mystery Solved in Part by Field Museum Scientists]

“People don’t know how to classify it taxonomically,” Field Museum Fossil Invertebrates Collections Manager Paul Mayer said. “What group of animals did it belong to?  Was it a gastropod that didn’t have a shell? Was it some kind of worm like a leech? Or was kind of chordate, or a jawless fish? People have gone back and forth on these type of ideas. Now finally with the publication, we’ve determined it is a vertebrate.”

But how could such a bizarre creature live in Illinois? Roughly 307 million years ago, Illinois was a very different place.

“It was a very different and much more pleasant place to live,” Field Museum Curator of Invertebrate Paleontology Scott Lidgard said. “It was a tropical environment and that is because it was only a few degrees north or south of the equator for this entire interval of time.”

Mayer said that the Tully Monster’s classification was a puzzle for decades.

“It solves a mystery that the Tully monster has been kind of the poster child for problematic fossils – a mystery for 50 years – that people have been wondering, ‘What is this animal?’” Mayer said. “It starts filling in some blanks on the tree of life.”

The Field Museum created the video below, "Tully: Monster versus Method," to show more about the technology and methodology behind the Tully monster breakthrough. 

Tully: Monster vs Method from The Field Museum on Vimeo.


Related 'Chicago Tonight' stories

Illinois ‘Monster’ Mystery Solved in Part by Field Museum Scientists

March 16: Just over 307 million years ago, Illinois was home to a bizarre creature dubbed the Tully monster. The aquatic animal had a tube-shaped body, skinny snouts ending in a toothy jaw or claw, and Shrek-like eyes at the end of little stalks.


Unpacking One Terra-Cotta Warrior at the Field Museum
Watch what it takes to transport the life-sized Chinese statues.


Field Museum Rediscovers Beetle First Collected by Charles Darwin
Until recently, when the beetles began to be individually imaged, no one had any idea that one particular rove beetle had originally been collected by the famous English naturalist Charles Darwin.


Fish at Field Museum is Only One of its Kind in Existence
At first glance, the formaldehyde-soaked Evarra tlahuacensis doesn’t come off as a terribly striking fish. But the little minnow is actually the only remaining specimen of its kind on Earth – and it lives in Chicago.


Thanks to our sponsors:

View all sponsors

Thanks to our sponsors:

View all sponsors

Neighborhood: