New Whale Fossil Species Sheds Light On Evolution Of Echolocation

March 13, 2014

Image Caption: An artistic reconstruction of the 28 million-year-old Cotylocara macei as it patrolled the shallows near present-day Charleston, South Carolina. Credit: Artwork by Carl Buell/NYIT

Lawrence LeBlond for redOrbit.com Your Universe Online

Echolocation is an important tool for several modern species, including bats and some birds. Previous research from New York Institute of Technologys College of Osteopathic Medicine has found that this powerful navigational tool also existed in a 28-million-year-old relative of modern-day toothed whales, dolphins and porpoises.

In new research, published in the journal Nature, Associate Professor Jonathan Geisler, of NYIT, and colleagues studied a new fossil species, Cotylocara macei, which had been discovered near Charleston, South Carolina.

Geisler noted that the most important conclusion in his teams research involves the evolution of echolocation and the complex anatomy that underlies this behavior.

This was occurring at the same time that whales were diversifying in terms of feeding behavior, body size, and relative brain size,he added.

In most mammals, including humans, low frequency sounds are produced in the larynx. In toothed whales, dolphins and porpoises, however, high-frequency sound is produced through a constricted area in the animals nasal passages below the blowhole. This sound-producing mechanism in toothed whales is very complex, consisting of large muscles, air pockets and bodies of fat all packed into a small region of the face.

The evolution of complex adaptations have been studied widely and new fossil discoveries have often revealed that adaptations evolve in a step-wise fashion and usually over long periods of geologic time. In the study of the C. macei skull, Geisler and his colleagues concluded that this whale echolocated similarly to its modern-day relatives.

Its dense bones and air sinuses would have helped this whale focus its vocalizations into a probing beam of sound, which likely helped it find food at night or in muddy water ocean waters, Geisler said in a statement.

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New Whale Fossil Species Sheds Light On Evolution Of Echolocation