The clams, Nymphalucina occidentalis, once lived in what is now South Dakota, where an inland sea divided western and eastern North America. While examining the shells, now at the American Museum of Natural History in New York, paleontologists Adiël Klompmaker of the University of Alabama in Tuscaloosa and AMNH’s Neil Landman spotted telltale oval-shaped holes. Each hole was between 0.5 and 1 millimeters in diameter, thinner than a strand of spaghetti.
A modern octopus uses a sharp ribbon of teeth called a radula on its tongue to drill a hole into thick-shelled prey — useful for when the shell is too tough for the octopus to pop apart with its suckers. The octopus then injects venom into the hole, paralyzing the prey and dissolving it a bit, which makes for easier eating. Octopus-drilled holes were previously found in shells dating to 50 million years ago, but the new find suggests this drilling habit evolved 25 million years earlier in their history.
A modern octopus uses a sharp ribbon of teeth called a radula on its tongue to drill a hole into thick-shelled prey — useful for when the shell is too tough for the octopus to pop apart with its suckers. The octopus then injects venom into the hole, paralyzing the prey and dissolving it a bit, which makes for easier eating. Octopus-drilled holes were previously found in shells dating to 50 million years ago, but the new find suggests this drilling habit evolved 25 million years earlier in their history.
