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Dinosaur of the day - mummified-o-saurus - December 03, 2007

A dinosaur complete with skin, tendons and perhaps even internal organs has been uncovered in the US. Although it is being billed as "mummified", the skin and tissues on this hadrosaur have actually been turned to stone. Crucially however, they have been preserved.

"This is not a skin impression," Phil Manning of the University of Manchester told Reuters. "This is fossilized skin. When you run your hands over this dinosaur's skin, this is the closest you are going to get to touching a real dinosaur, ever."

Rapid deposition of mineral-rich sand over the carcass of ‘Dakota' probably preserved the tissue (press release, photo gallery).

The fossil was originally discovered by grad student Tyler Lyson in North Dakota in 1990, hence the imaginative name. In 2004 he returned to it and uncovered the skin. At that point Manning was called in. "When I first saw it in the field, (I thought) ‘Shiiiit, that's a really well preserved dinosaur'," he says (Wired).

After being encased in plaster the beast was hauled to a giant CT scanner for analysis of the tissue. And this tissue could force us to reassess a lot of what we though about dinosaurs. For starters the dinosaur's rump was larger than had been thought from other specimens. That means it could run faster than had been thought, comfortably leaving T Rex in its dust. Its vertebrae were also more spaced out than was thought to have been the case, which may force up estimates of overall size (Daily Telegraph, Washington Post, Times).

No peer reviewed studies on Dakota have been published as yet but it does feature on a forthcoming National Geographic TV programme (for US readers: Dino Autopsy, National Geographic Channel, December 9 at 9 p.m. EST/10 p.m. PT).

This isn't the first time dinosaur soft tissue has been detected, previous examples surfacing in Nature itself (in Italy and in China). It remains to be seen where this new find leaves the bald vs feathers debate.

Image: National Geographic Channel / Television

Posted by Daniel Cressey on December 03, 2007

Life between the (mica) sheets - December 05, 2007

The first life on Earth began in the protected spaces between sheets of mica. So says Helen Hansma, of the University of California, Santa Barbara.

Presenting her hypothesis at this week's American Society for Cell Biology, Hansma says her ‘soup and sandwich' is more plausible than the rival idea of life appearing in a prebiotic soup. Mica, she thinks, provides ideal conditions for molecules to organise into cells. She cites the chemical and physical similarities between a cell interior and the space between mica sheets - they are both being potassium-rich and negatively-charged. Movements of mica sheets could have helped shift molecules and triggered bond formation between them (press release one, press release two).

Nature's Brendan Maher is blogging the conference at the In The Field blog:

While looking at a chunk of mica under a microscope one day, she noticed bits of organic gunk growing in between it's flaky layers and thought, "Hey that would be a neat place for an organism to thrive." Having spent years tuning atomic force microscopes to observe biomolecules on mica sheets, she knew how amenable the structure of mica is to interaction. Another clue had her hooked on the hypothesis. No one, she says, has ever adequately explained how cells first obtained potassium.

The story also appears on LiveScience/Fox News and Xinhua.

Image: sketch showing hypothesis for the evolution of different types of biological molecules in the spaces between mica sheets. Image width is ~50 nm. Courtesty Helen Greenwood Hansma, UC Santa Barbara

Posted by Daniel Cressey on December 05, 2007 / http://blogs.nature.com/news/thegreatbeyond/2007/12/life_between_the_mica_sheets.html