If Anomalocaris Is Innocent, Who Killed All Those Trilobites?

Oooh! Intriguing! A new twist in our favorite mystery from the Paleozoic era’s Cambrian period. Mount Holyoke paleontologist Mark McMenamin thinks there’s something fishy about his colleague James “Whitey” Hagadorn’s work concerning Anomalocaris, a giant shrimp-like creature conventionally believed to have preyed upon hard-shelled trilobytes, whose broken, apparently bitten exoskeletons are a well-established part of Cambrian oceans’ fossil record. “I’m a bit skeptical about Whitey Hagadorn’s conclusions regarding Anomalocaris,” McMenamin said, of findings Hagadorn presented at the annual meeting of the Geological Society of America in Denver yesterday.

Using a 3-D computer model of Anomalocaris anatomy based on 505 million-year-old fossils, Hagadorn (who has apparently switched from Amherst to the Denver Museum of Nature & Science in the year since the Awl started covering this story) determined that Anamolocaris mouth-parts were soft and rubbery: suited only for a diet of jellyfish and worms or filtered plankton, physically incapable breaking trilobyte shells.

Or so he says.

“The damage to those Cambrian trilobites is real,” says McMenamin. “And if it was not Anomalocaris’s doing, who then was the predator? If Hagadorn is right and Anomalocaris could only gum its prey, then the search is on for the actual durophagous (that is, shell-cracking) Cambrian predator.”

It’s totally going to turn out that Hagadorn did it himself.