Joel Kontinen
Hardly a week goes by without the discovery of soft tissue in fossils assumed to be tens if not hundreds of millions years old.
Soft tissue has been found in many kinds of creatures, for instance salamanders, dinosaurs, marine creatures (read more here and here), birds (read more here and here), in a “520 million year” old Cambrian creature and microfossils assumed to be 1.88 billion years old.
The latest instalment features an emu-sized dinosaur dubbed Citipati osmolskae found in Mongolia, assumed to be 75 million years old.
Phys.org gives some background facts and a brief summary of a paper published recently in the journal Proceedings of the Royal Society B:
The dinosaur was “preserved while brooding its eggs, also preserved the original keratinous claw sheath that covered its digits… In 1995, a particularly well-preserved specimen of Citipati was recovered from the Djadokhta formation. The specimen was found in a brooding position on a nest of eggs. Paleontologists theorized that it was rapidly buried by a sand dune, which explained its excellent preservation.”
While preparing the specimen, researchers at the North Carolina State University
“noticed that there was a thin lens of white material extending beyond one of the bony claws on a forelimb that differed in texture and color from both the sediment and the bone. It was also located where a claw sheath would be.”
The Phys.org writer could not resist bringing up the assumed dino-to-bird connection:
“In modern birds, claw sheaths cover the claw at the end of a digit much like fingernails in humans and serve a number of functions - aiding them in defense, movement, or catching and holding prey. The sheaths in modern birds are composed of two types of keratin: alpha-keratin, the softer form found on the interior of the sheath; and beta-keratin, a harder and more durable keratin that comprises the sheath's exterior.”
We might perhaps wonder whether this change of focus has to do with the enigma of preserving original proteins for 75 million years.
Now they suggest that calcium did the trick. But the evidence is very flimsy indeed.
Looks like it’s high time to throw the millions of years dogma overboard.
Source:
Original dinosaur claw sheath proteins preserved for 75 million years. Phys.org. 8 November 2016.
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