A drainage ditch in South Carolina recently provided the paleontology community with a remarkable find. It was there in Berkeley County that a new fossil species, Cotylocara macei, was discovered. In a paper that appeared in Nature on March 12th, 2014, Jonathan H. Geisler, lead author of the study and a member of the Department of Anatomy at the New York Institute of Technology, wrote about the implications of the new find.
Cotylocara macei is an ancient whale that dates back to the Oligocene epoch 28 million years ago. Geisler and his team’s analysis of the skull shows that the whale once used echolocation to navigate and stalk its prey. Echolocation involves emitting concentrated sound signals and using their resultant echoes to determine the locations of the objects that the sound bounces off. Dolphins, killer whales, sperm whales, porpoises, some species of bats and birds use this navigation technique today.
The discovery of Cotylocara is significant because it is the oldest example of echolocation in marine animals, showing that the technique evolved far earlier than previously known. Geisler’s analysis points out that its skull has air pockets and an asymmetry similar to the skulls of porpoises and dolphins, “a rudimentary form of echolocation evolved in the early Oligocene, shortly after odontocetes (toothed whales) diverged from the ancestors of filter-feeding whales” write the authors in their study. This pushes back the evolution of the ability to echolocate to around 32 million years ago.
Geisler, J. H., Colbert, M. W., & Carew, J. L. (2014). A new fossil species supports an early origin for toothed whale echolocation. Nature, 508(7496), 383-386.
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