Bizarre Tully Monster Sea Creature Was a Vertebrate Say Yale Researchers

Posted on March 16, 2016

Scientists have determined that the unusual looking ancient sea monster known as the Tully Monster was a vertebrate. The creature inhabited the ancient seas about 300 million years ago.

The first fossil of the Tully Monster was discovered in 1957 in Illinois by amateur fossil hunter Francis Tully. He found it in a coal mining pit. The creature has the scientific name of Tullimonstrum gregarium. Thousands of Tully Monster fossils were later found at the site. The Field Museum has 2,000 specimens.

A team of paleontologists led by Yale researchers analyzed the specimens at the Field Museum using new techniques like synchrotron elemental mapping, which illuminates an animal's physical features by mapping the chemistry within a fossil. They determined the Tully Monster had gills and a notochord. The notochord functioned as a rudimentary spinal cord and primitive backbone for the creature. These features had not been previously identified.

Victoria McCoy, lead author of the study, says in a statement, "I was first intrigued by the mystery of the Tully Monster. With all of the exceptional fossils, we had a very clear picture of what it looked like, but no clear picture of what it was."

She also says, "It's so different from its modern relatives that we don't know much about how it lived. It has big eyes and lots of teeth, so it was probably a predator."

A New York Times story says over 1,200 Tully monster specimens. The notochord discovery came when they noticed a lightly colored structure in the creature's gut. The article says the creature had a vertebrate that most closely resembles that of the lamprey.

The Tully monster is the official fossil of the state of Illinois. Here is a 2011 video about the Field Museum's Tully Monster collection from The Field Museum:

Image: Sean McMahon/Yale University

ANIMALS