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Pre-historic daddy long legs shunned evolution, reveal scientists

posted 12 Oct 2011, 03:35 by Mpelembe Admin

3-D scanning technique allows scientists to see how little a prehistoric arachnid has changed over all their time time on earth. The insect, commonly called a daddy long legs, pre-dates the dinosaurs, living in forests in the Carboniferous period more than 300 million years ago. Jim Drury reports.


REUTERS / IMPERIAL COLLEGE LONDON - The daddy long legs is a common sight in British houses at this time of year.


But the eight-legged arachnid is far from dull, dating back to before the dinosaurs roamed the Earth.

And London-based scientists have revealed a startling new fact - the creature has barely evolved in 300 million years.

Dr Mark Sutton led the research team from Imperial College London.

They used state-of-the-art computed tomography to create detailed 3D models of two varieties - Dyspnoi and Eupnoi.


MARK SUTTON, SENIOR LECTURER AT IMPERIAL COLLEGE LONDON AND SUPERVISOR OF 'HARVESTMEN' PROJECT TEAM, SAYING:

"If you imagine taking a complicated three-dimensional object, splitting it down the middle, and looking what you've got you don't really get a very good idea of what's going on. You just see one surface. But using modern CT scanning technology we can extract the entire fossil, get the whole thing out, move them into the virtual realm and produce these virtual fossils."

Sutton said the work had been painstaking.


MARK SUTTON, SENIOR LECTURER AT IMPERIAL COLLGE LONDON AND SUPERVISOR OF 'HARVESTMEN' PROJECT TEAM, SAYING:

"It takes the fossil, you put it on a turntable and it shines X-rays through it to take a picture at the back like a normal X-ray and then it rotates it slightly and it does it again, it takes it again, and it does it again repeatedly for about three thousand different shots rotating very slowly for a full circle. That data that this produces, this series of rotational X-ray images using complicated computer algorhythms can be stitched into virtual slices of the specimen which show every RRevel inside and we can take those slices and with more computer jiggery-pokery turn those into 3D models."

The fossils show clear differences between the varieties of daddy long legs, also known as harvestmen.

Researchers believe the spikes on the back of The Dyspnoi provided it with protection from predators.

The Eupnoi's elongated limbs provided the same function.

But it's the lack of evolution that most interests Sutton.


MARK SUTTON, SENIOR LECTURER AT IMPERIAL COLLEGE LONDON AND SUPERVISOR OF 'HARVESTMEN' PROJECT TEAM, SAYING:

"These very early ones are surprisingly like modern ones. It's a group that hasn't really done very much. It's obviously found a way of living that works and has decided not to change it and that mode of life has been perfectly stable despite all the vast number of changes within the last 300 million years. The creatures today look much the same as they did then."


Until now most people have thought harvestmen barely worthy of a second glance.

But these 3D models are set to revolutionise their image, marking the daddy long legs as the unchanging, great grand-daddy of the arachnid world.


Jim Drury, Reuters

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