Underwater sonar may have developed 34 million years ago
James Carew and Mitchell Colgan
The skull of a newly identified species of extinct toothed whale may help scientists piece together when echolocation evolved underwater.
Recovered from a drainage ditch in South Carolina, the 28-million-year-old fossil has a deep pit in the top of its head that divides the right and left sides of the skull. “It’s a highly unusual feature,” says Jonathan Geisler, an anatomist at the New York Institute of Technology in Old Westbury, adding that no other known whale, dolphin or porpoise has such a pit. “It’s really bizarre.”
Geisler and his colleagues named the species Cotylocara macei (the genus name means “cavity head” in Greek). The pit and other skull features suggest that the ancient toothed whale used echolocation to send calls out into the water. The age of the skull and the animal’s relationship to other extinct whales suggest that the basic anatomy for echolocation developed shortly after toothed