The Tully monster, the mysterious soft-bodied fossil found in Illinois in the 1950s, has been determined to be a vertebrate "on the stem lineage to lampreys," solving a decades old debate, according to the
Chicago Tribune.
Work on moving Tullimonstrum gregarium, or the Tully monster, into a new biological category was described in a paper published Wednesday in the science journal
Nature.
Francis Tully, a Texaco pipefitter and amateur fossil hunter, first discovered the prehistoric fossil in 1955 in a coal mining area near Morris, Illinois, said the Tribune.
Some 2,000 Tully specimens at the Field Museum of Natural History in Chicago were examined using synchrotron X-ray from the U.S. Department of Energy's Advanced Photon Source at Argonne National Laboratory for the breakthrough, noted the Tribune.
Scientists from Yale University and the American Museum of Natural History joined in the research that made the discovery.
"I was first intrigued by the mystery of the Tully Monster," said Victoria McCoy, the lead author of the Nature study, to a
University of Chicago news release. "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."
McCoy was part of a Yale University team of paleontologists that determined that the 300-million-year-old foot-long animal was a vertebrate with gills and a stiffened rod, or notochord, which supported its body.
Carmen Soriano, a beamline scientists at Argonne and a coauthor of the study, said the x-ray allowed researchers to have a more detailed took at the fossils.
"Until now, the Tully Monster had no clear affiliation inside the animal world," Soriano said in an
Argonne National Laboratory release. "Our understanding of this extinct creature has been greatly improved.
"It is very satisfying to know that the (Advanced Photon Source) had a significant role in allowing scientists to finally determine what position on the tree of life the Tully Monster belongs to, ending a scientific debate that has gone on since the Field Museum obtained its first fossil samples of the creature more than 50 years ago."
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