April 20, 2011

Largest Ever Spider Fossil Found In Mongolia

A fossilized spider, uncovered in inner Mongolia, is thought to be the largest ever spider fossil discovered. It has been so perfectly preserved from 165 million years ago that scientists have identified it down to the exact species and that is was an adult female, BBC News reports.

This specimen was uncovered from at a site called Daohugou in Inner Mongolia, also home to areas filled with fossilized salamanders, small primitive mammals, insects and water crustaceans.

This fossilized Golden Orb Weaver has been named Nephila jurassica and is roughly the size of the spider's modern-day descendants, with a body one-inch long and more than half an inch wide, and legs that stretch to 2.5-in, Mail Online is reporting. It spun webs in the jurassic era forests of northern China when the region was nearly tropical.

Paleontologist Professor Paul Selden, of Kansas University, explains that Golden Orb Weavers are common but spectacular inhabitants of tropical and subtropical regions with females weaving distinctive 5-ft wide webs of yellow silk that appear golden in the sunlight.

Microscopic examination of the female revealed clear details including the brushes of long bristles on the ends of her legs that are characteristic of the Golden Orb Weaver.

This particular spider met its demise encased in volcanic ash at the bottom of what would have been a lake. The preservation of detail found in the fossil exquisite. Spider fossils from this period are rare, because the arachnids' soft bodies are easily destroyed.

Professor Selden explained, "You see not just the hairs on the legs but little things like the trichobothria which are very, very fine. They're used to detect air vibrations. There's a very distinct group of them and they're a very distinct size which is typical of this genus, Nephila."

The researchers report their find in the journal Biology Letters.


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