Earful of data hints at ancient fish migration
By Sid Perkins
Small growths that developed in the ears of fish more than 65 million years ago are providing a wealth of information about the species’ environment and lifestyle.
The fish, Vorhisia vulpes, lived in a broad, shallow seaway that stretched from present-day Texas to the Arctic Ocean. Scientists know the creature only by its distinctive otoliths, which is Greek for “ear stones.” Those features develop during most stages of a fish’s life and show numerous growth rings, says Scott J. Carpenter, a geochemist at the University of Iowa in Iowa City. The ratios between carbon isotopes and between oxygen isotopes in an otolith layer offer clues about the fish’s environment when that material was deposited, says Carpenter.