- News Home
5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Fossil Sea Spider Goes Digital
20 October 2004 (All day)
A lucky fossil find and a novel imaging technique have brought researchers closer to understanding the mysterious origins of the sea spider, a spindly arachnid that dwells on the ocean floor.
Sea spiders look much like the common "daddy long leg" spiders, with thin, long legs and a tiny torso. Although they seem to be related to land spiders, they also possess some unusual anatomy--including special compartments on their heads for carrying eggs--that suggest they may deserve their own branch of the arachnid family tree. Scientists have struggled to solve the mystery, in part because the delicate sea spiders are rarely preserved as fossils.
That's why University of Oxford paleobiologist Derek Siveter was elated when he and colleagues found the oldest and most complete sea spider fossil to date in Herefordshire, United Kingdom. The fossil, which dates back some 425 million years, was too delicate to excavate by traditional means, so the researchers took digital images of the fossil at 20-micrometer intervals as they ground through the surrounding rock. The team reconstructed the slices in a computer, creating highly detailed, three-dimensional pictures of the specimen that can be rotated or dissected at will, the researchers report in the 21 October issue of Nature. The images have led Siveter to conclude that sea spiders are close relatives of land spiders after all. The presence of pincerlike claws called chelae means that they should be grouped with spiders, scorpions, and horseshoe crabs, all of which possess the distinctive feature. The fossil also "has all the hallmarks of current-day sea spiders," Siveter says, suggesting that sea spiders emerged as a distinct group about 450 million years ago. Siveter's team has produced a "a jaw-droppingly beautiful representation" of the fossil, says Rich Palmer, an invertebrate zoologist at the University of Alberta, Edmonton. "The details are astounding," he says. The study "fills a gap in the fossil record with an extremely well-preserved specimen" and may provide valuable clues about a species that has been "virtually ignored by zoologists," adds Jason Dunlop, curator for arachnids at the Museum für Naturkunde der Humboldt-Universität in Berlin, Germany.