Not-dino of the day? - July 30, 2008
A high-profile discovery of T Rex tissue is nothing of the sort, according to a paper published today in PLOS One.
Thomas Kaye of the Burke Museum of Natural History in Seattle says what have previously been presented as remnants of blood vessels are actually just modern bacterial slime.
“Mineralized and non-mineralized coatings were found extensively in the porous trabecular bone of a variety of dinosaur and mammal species across time,” write Kaye and colleagues. “They represent bacterial biofilms common throughout nature.”
A combination of electron microscope work and carbon dating on dino bones shows that what others have identified as ‘blood vessels’ are actually just casts formed by bacteria inside bones, they say.
“We are not experts in the field. We are not disagreeing with the fact that their instruments detected protein,” Kaye told Reuters. “We are offering an alternative explanation.”
Mary Schweitzer, a North Carolina State University researcher who reported dino soft tissue in 2005, has rejected the claims. “The idea that biofilms are completely and solely responsible for the origin or source of the structures we reported is not supported,” she told USA Today.
Over on Wired, Dixie State College of Utah paleontologist Jerry Harris is keeping the peace:
The field of investigating fossil bones at this scale and with these kinds of procedures is still so new that there really isn't a substantial enough body of data yet for people to even argue about. That the two produced different results doesn't necessarily mean either one is wrong. It simply means that lots of questions remain unanswered.
Image: stock photo / Alamy
Comments
Creationists might insist this is an effort to suppress the “damage” that so-called soft tissue preservation does to science. Schweitzer, and her colleagues will undoubtedly defend their results, which creationists will distort into the evilutionist thought police attempting to silence Schweitzer (who happens to be an evangelical Christian).
There were two early papers by Schweitzer that I recall to have addressed some of the arguments in the PLOS article, specifically pyritic framboids were discussed in one of the PNAS articles. The new energy dispersive spectroscopy (EDS) results seem conclusive that the “blood cells” were framboids. I once asked Schweitzer if she would be interested in a trace element analysis by scanning tunneling microscopy of her dissertation material, but she had basically used it all up, and there were no voucher specimens for further analysis. This was too bad, but not a surprise given the number of different studies that had been done on what was very little bone.
There was also an amino acid racemization result that I thought clearly argued against modern contamination. Also several times she (or coauthors) have at least mentioned the notion that bacteria could have “reworked” the original material (IIRC). The new paper does not seem to account for the immunological data, either from her dissertation or the later work she published. However, the infrared spectra in Fig 9 of Kaye et al 2008 holds considerable interest with implications to other studies of fossil collagen, eg;
Embery G, Milner AC, Waddington RJ, Hall RC, Langley MS, Milan AM. 2003 “Identification of proteinaceous material in the bone of the dinosaur Iguanodon” Connect Tissue Res Vol. 44 Supplement 1: 41-6.
Gurley, L., Valdez, J.G, Spall, W.D., Smith, B.F., and Gillette, D.D. 1991 “Proteins in the fossil bone of the dinosaur, Seismosaurus” Journal of Protein Chemistry, 0(1): 75-90.
Schweitzer and Horner (1999) addresses this issue of cellular preservation directly. The observed structures are not red blood cells -
And
See also Dino-blood and the Young Earth
Well, how about this for a proposal: The organics, including bacteria, were of ancient source. The bacteria persist as spores over vast periods of time when the bone is desiccated, but periodically the bone is water saturated and they reactivate (with less and less success due to our old friend, the second law of thermodynamics). The resulting biofilm is unusually hardy - more like a massively cross linked plastic than a tissue. The amino acids are racemic! This means that the sources of the bacterial amino acids are ancient, and (IMHO) the bacteria were probably using both L- and D- aa’s anyway.
I like it.
Posted by: Gary Hurd | July 30, 2008 08:25 PM
Perhaps this find is of the fungus kingdom?
Posted by: Jaon | July 31, 2008 06:03 AM