Amber-Encased Mite Found Clinging to Fossil Spider

Mercredi, 09 Novembre 2011 17:00

Amber-Encased Mite Found Clinging to Fossil Spider

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By Mark Brown, Wired UK

Paleontologists from the University of Manchester have used X-ray tomography scanning techniques to image a microscopic mite, who was hitching a ride aboard a spider some 50 million years ago.

The 176-micrometre-long bug and its burly-looking dysderidae spider friend were trapped in tree resin during the Paleogene era, which then hardened and became translucent orange amber. By using a CT scan, researchers were able to peer inside and build a 3D model of the tiny animals.

“Amber is a remarkable repository of ecological associations within the fossil record,” said David Penney, from Manchester’s faculty of life sciences, in a press release. “In many cases organisms died instantaneously and were preserved with lifelike fidelity, still enacting their behavior immediately prior to their unexpected demise.”

This gives researchers an absolutely unprecedented peek into a moment in history, and provide clear evidence of behavior and interaction. “The remarkable specimen is the kind of find that occurs only once in say a hundred thousand specimens,” says Penney.

What it tells us is that phoresy — the now-common behavior of one animal using a completely different species for transportation — has been around for at least 50 million years in these mites.

CT scanning is a major boon to biology, argues Manchester’s Richard Preziosi. “We can now use a multidisciplinary approach to extract the most information possible from such tiny and awkwardly positioned fossils, which previously would have yielded little or no substantial scientific data,” he said in the release.

This is perhaps the smallest arthropod fossil to ever be captured in this way, and the oldest record of the family Histiostomatidae (which is still alive, in the likes of the pitcher plant mite, which is found within the pitcher leaves of North American purple pitcher plants.)

Jason Dunlop, from Humboldt University in Berlin, said in the release that “work like this is breaking down the barriers between palaeontology and zoology even further.”