'Tully monster' mystery is far from solved, group argues

Date: February 20, 2017

Source: University of Pennsylvania

Last year, headlines in The New York Times, The Atlantic, Scientific American and other outlets declared that a decades-old paleontological mystery had been solved. The "Tully monster," an ancient animal that had long defied classification, was in fact a vertebrate, two groups of scientists claimed. Specifically, it seemed to be a type of fish called a lamprey.

The problem with this resolution? According to a group of paleobiologists led by the University of Pennsylvania's Lauren Sallan, it's plain wrong.

"This animal doesn't fit easy classification because it's so weird," said Sallan, an assistant professor in Penn's School of Arts & Sciences' Department of Earth and Environmental Science. "It has these eyes that are on stalks and it has this pincer at the end of a long proboscis and there's even disagreement about which way is up. But the last thing that the Tully monster could be is a fish."

In a new report in the journal Palaeontology, Sallan and colleagues argue that the two papers that seemingly settled the Tully monster debate are flawed, failing to definitively classify it as a vertebrate. The mystery of the Tully monster, known to scientists as Tullimonstrum gregarium, remains.

"It's important to incorporate all lines of evidence when considering enigmatic fossils: anatomical, preservational and comparative," said Sam Giles, a junior research fellow at the University of Oxford and coauthor of the study. "Applying that standard to the Tully monster argues strongly against a vertebrate identity."

Read more