Largest Fossil Spider Found in Volcanic Ash
Charles Q. Choi, LiveScience Contributor
Date: 19 April 2011 Time: 07:01 PM ET
Fossil female golden orb-weaver spider (Nephila jurassica) from the Middle Jurassic of China.
CREDIT: Paul Selden.
CREDIT: Paul Selden.
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 cm) long. Golden orb-weavers nowadays are mainly tropical creatures, so the ancient environment of Nephila jurassicaprobably was similarly lush. [Image of fossil spider]
"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," 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 numbers in check. So these findings help us "understand the evolution of the insect-spider predator-prey relationship," Selden said, suggesting that golden orb-weavers have been ensnaring insects and influencing their evolution since the Jurassic Period. [Read: Ancient Spider Guts Revealed]
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Oldest true orb-weaving spider (Araneae: Araneidae)
-Author Affiliations
1School of Earth, Atmospheric and Environmental Sciences, The University of Manchester Manchester M13 9PL, UK
2Departamento de Zoología y Antropología Física, Universidad de AlcaláAlcalá de Henares, Madrid 28871, Spain
Author for correspondence (david.penney@manchester.ac.uk)
Abstract
The aerial orb web woven by spiders of the family Araneidae typifies these organisms to laypersons and scientists alike. Here we describe the oldest fossil species of this family, which is preserved in amber from Álava, Spain and represents the first record of Araneidae from the Lower Cretaceous. The fossils provide direct evidence that all three major orb web weaving families: Araneidae, Tetragnathidae and Uloboridae had evolved by this time, confirming the antiquity of the use of this remarkable structure as a prey capture strategy by spiders. Given the complex and stereotyped movements that all orb weavers use to construct their webs, there is little question regarding their common origin, which must have occurred in the Jurassic or earlier. Thus, various forms of this formidable prey capture mechanism were already in place by the time of the explosive Cretaceous co-radiation of angiosperms and their flying insect pollinators. This permitted a similar co-radiation of spider predators with their flying insect prey, presumably without the need for a ‘catch-up lag phase’ for the spiders.Keywords:
Footnotes
Received April 26, 2006.
Accepted May 22, 2006.
© 2006 The Royal Society
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