Printer Friendly

Facing up to a backwards fossil.

Facing up to a backwards fossil

Fossils of primitive, jawless fish dating back 470 million yearsare the oldest known examples of vertebrates, a subphylum to which both human beings and salamanders belong. Because the evidence of these fish, called agnathans, is scant and fragmentary, scientists know little about the agnathans' appearance or about their evolutionary history. However, one scientist is discovering new information simply by turning around a "backwards' fossil.

This fossil is one of a handful of the earliest known agnathanfossils, all of which date back to the Ordovician period. In a reexamination of the fossil, David K. Elliott from Northern Arizona University in Flagstaff realized that "the person who had described it had somehow gotten it back to front.'

Because of this error, the fossil had been dismissed as aheadless, tailless mass of scales and plates. But in the July 10 SCIENCE, Elliott reports that both head and tail are well preserved, making this the most complete vertebrate known from the Ordovician, he says.

Because of new information discovered by the fossil turnaround,Elliott believes that this fossil and several similar ones had been inappropriately assigned to an order of fish, Heterostraci, whose members have only a single set of tube-like openings that run to the gills. Elliott, however, has found several sets of openings on the reexamined fossil.
COPYRIGHT 1987 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1987, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:reexamination of agnathans fossil
Publication:Science News
Date:Jul 18, 1987
Previous Article:Why vitamin A may fight infections.
Next Article:Pulling each other through bad times.

Related Articles
Psst ... wanna buy a T. rex? Paleontologists fret about dinosaur sales.
Yolks of yore: oldest animals found.
All mixed up over birds and dinosaurs.
Unified erectus: fossil suggests single human ancestor.
Feathery find: scientists unearth evidence that some dinosaurs sported feathers.
American forces press service (Oct. 3, 2005): Pace issues guidance to help military 'shape the future'.
Tax measure fails by wide margin.
Incumbent Hall, newcomer McCown capture LCC seats.

Terms of use | Copyright © 2016 Farlex, Inc. | Feedback | For webmasters