Wednesday, 26 March 2014

Unprecedented paleontology discovery prompts scientists to change thinking

Drexel University

Ancient sea turtle bones found 163 years apart are a perfect match. Photo courtesy Drexel University
At first, it was jokingly suggested that a partial ancient sea turtle bone discovered in a New Jersey stream bed by an amateur paleontologist in fall of 2012 was the missing half of a 163-year-old fossil housed at the Academy of Natural Sciences at Drexel University.
The fossil, a humerus (the large upper-arm bone), was broken in half. Could the missing half found by Gregory Harpel and donated to the New Jersey State Museum actually be the other half of the bone from the same ancient sea turtle that was discovered in 1849?
Scientists were determined to find out.Continue reading....

“I didn’t think there was any chance in the world they would actually fit,” said Jason Schein, assistant curator of natural history at the New Jersey State Museum, according to DrexelNow.
But they did. The two bones were a perfect match.
The broken bones of the ancient sea turtle were scanned front and back in 3D to show their surface. Photo by Jesse Pruitt, Idaho Museum of Natural History
“As soon as those two halves came together, like puzzle pieces, you knew it,” said Ted Daeschler, associate curator of vertebrate zoology and vice president for collections at the Academy of Natural Sciences.
“Sure enough, you have two halves of the same bone, the same individual of this giant sea turtle. One half was collected at least 162 years before the other half.”
The discovery, announced Tuesday by the Academy of Natural Sciences of Drexel University, enabled scientists to deduct two things: That not all fossils found in exposed strata rock break down from exposure to the elements within a few years as first thought, and that this ancient sea turtle was the largest of its kind in history, measuring 10 feet from tip to tail.
“And we would have never known that if we hadn’t been able to unite these two pieces,” Daeschler said.
Here is video from Drexel University about the discovery:
“The astounding confluence of events that had to have happened for this to be true is just unbelievable, and probably completely unprecedented in paleontology,” Schein said.
Harpel was fossil hunting when he came across the ancient sea-turtle bone on a grassy embankment a bit upstream from a brook in Monmouth County, New Jersey, where he usually hunts.
“I picked it up and thought it was a rock at first; it was heavy,” Harpel said.
Realizing it was a fossil, he took it to the New Jersey State Museum, where scientists thought it looked familiar, since they knew of a similar partial bone at Drexel. That prompted the unique discovery.
Credit- Jason Poole, Academy of Natural Sciences of Drexel University
Artist’s rendering of what the ancient sea turtle looked like, based on the broken bones pieced together; illustration courtesy Jason Poole, Academy of Natural Sciences of Drexel University

The Academy’s older bone was also without a match of any kind, making a perfect match seem even more farfetched: It was originally named and described by famed 19th-century naturalist Louis Agassiz as the first, or type specimen, of its genus and species, Atlantochelys mortoni. In the intervening years, it remained the only known fossil specimen from that genus and species.[…]
Now, the scientists are revising their conventional wisdom to say that, sometimes, exposed fossils can survive longer than previously thought. They report their remarkable discovery in the forthcoming 2014 issue of the Proceedings of the Academy of Natural Sciences of Philadelphia. The find is also featured in the April 2014 issue of National Geographic magazine, on newsstands now.
Incredibly, scientists believe the entire unbroken bone was embedded in sediment 70 million to 75 million years ago and broke in half millions of years later during the Pleistocene or Holocene eras, before the pieces became covered in sediment and protected from further deterioration until unearthed by man.

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