Largest Fossil Spider Found In Volcanic Ash

The largest fossil spider uncovered to date once ensnared prey back in the age of dinosaurs , scientists find.

The spider, Named Nephila Jurassica , was discovered buried in ancient volcanic ash in inner Mongolia, China . Tufts of hairlike fibers seen on its legs showed this 165-million-year-old arachnid to be the oldest known species of the  largest web-weaving spiders  alive today  ... the golden orb  weavers , or Nephila , which are big enough to catch birds and bats , and use silk that shines like gold in the sunlight.

The fossil was about as large as its modern relatives , with a body one inch (2.5 centimeters) wide and legs that reach up to 2.5 inches (6.3) long . Golden orb-weavers nowadays are mainly tropical creatures , so the ancient environment of Nephila  juassica probably was similarly lush .

"It would have lived , like today's Nephila  , in its orb web of golden silk in a clearing in a forest or more likely at the edge of a forest close to the  lake," says researcher Paul Selden , director of the Paleontological Institute at the University  of Kansas , told LiveScience . "There would have been volcanoes nearby producing the ash that forms the lake sediment it is entombed within."

Spiders are the most numerous predators on land today , and help keep insect-spider  predator-prey relationship," Selden said , suggesting that golden  orb-weavers  have  been ensnaring insects and influencing their evolution since the Jurassic  Period.

"There were many large or medium-sized flying insects around at that time on which it would have fed indiscriminately," Selden said.

In Modern golden orb-weavers species , females  are typically much larger than males . This new fossil was a female, suggesting this trend stretches back at laest as far as the Middle Jurassic , Selden said ... that is , back before the first known bird , Archaeopteryx , or giant dinosaurs  such as Brachiosaurus and Diplodocus.

Although this is the largest fossil spider known to date , it is not the oldest . Two species from Cosely, England , Eocteniza silvicola and Protocteniza britannica , both come from about  310 million years ago.

Selden and his colleagues are now investigating other  fossil spiders  from China , "as well as those from elsewhere in the world ... currently Brazil , New Zealand , Australia , Italy  and Korea," he said.