Scientists from the University of Witwatersrand in Johannesburg, South Africa, and the University of Chicago have uncovered a remarkably well-preserved fossil lamprey from the Devonian period that reveals today's lampreys as "living fossils" since they have remained largely unaltered for 360 million years.
Chicago's Michael Coates, PhD, joined Witwatersrand's Bruce Rubidge, PhD, and graduate student and lead author Rob Gess to describe the new find in the article, "A lamprey from the Devonian of South Africa" to be published in the Oct. 26, 2006, issue of Nature.
"Apart from being the oldest fossil lamprey yet discovered, this fossil shows that lampreys have been parasitic for at least 360 million years," said Rubidge, director of the Bernard Price Institute for Palaeontological Research.
Lampreys are long, eel-like parasites that attach themselves to and feed on other fish. Of the 46,000 known species of vertebrates, lampreys and hagfish are the only surviving jawless vertebrates. Lampreys are the most "primitive" of the vertebrates, meaning that they are the least changed from the first vertebrates. Besides lacking jaws, lampreys have no paired pectoral and pelvic fins, and no scales.
"This fossil changes how we look at lampreys today," said Coates, associate professor of organismal biology and anatomy. "They're very ancient, very primitive animals, yet with highly specialized feeding habits."
It reveals that the anatomical evolution of lampreys is more conservative than scientists thought, Coates added. Although they've gotten slightly longer, they specialized early and successfully and thus appeared to have stayed much the same for the past 360 million years.
"This discovery is a monument to the dedication and passion of [Gess], who has spent many months patiently excavating and unearthing the elusive secrets from the prehistoric past," Rubidge said.
Gess found the new specimen, Priscomyzon rinien
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Contact: Catherine Gianaro
catherine.gianaro@uchospitals.edu
773-702-6241
University of Chicago Medical Center
25-Oct-2006