Sunday, October 28, 2007

news paper article about fossile records of blue crabs

Corolla Crab is an Oldster
By Daryl L. Law, Hart Matthews/Sentinel Staff
Copyright ©1996 Outer Banks Sentinel

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Not too long ago, Jerry Alexander was kicking around the beach in Corolla when he stumbled across something from a long, long time ago. He found a fossil that scientists believe could be 1.5 million years old.

The Kill Devil Hills-based artist was looking for fulgurite, a tubular rock made when lightning strikes sand and fuses it into a "lightning rock," as he calls it.

But what Alexander came across had a fairly recognizable shape, one most seafood lovers would know as a blue crab.

"It's a Jimmy, and it's well done," Alexander jokes as he shows off his prized find.

The specimen is nearly complete, something that makes it rare. It weighs just less than 7 ounces and measures 5 inches from tip to tip, making it "a keeper," Alexander mused.

The crab is basically black, hard as a rock, and between its claws and body is calcite cement that is commonly found with fossils. Most of the legs and all of the body or carapace is intact.

"When I found it, I didn't notice it as a crab," Alexander said. "Then I brushed it off and said 'Voilà! What do I have here?'"

Alexander said he thought it might be a crab caught up in fulgurite, but three days after the find, he took it to a fossil seminar held at the N.C. Aquarium on Roanoke Island.

When visiting lecturer JoAnne Powell saw the crab, she knew it was an extremely old fossilized specimen. Alexander says everyone's eyes opened wide.

"I went over to the aquarium and stopped the show," he said. "Right away [he snaps his fingers] she said it could be 3 million years old. That's when man started walking upright if you believe in that evolution stuff.

Powell, the curator of education at the N.C. Maritime Museum in Beaufort, collects fossils as a hobby. In geologic time, her initial estimate was relatively close, give or take a million and a half years.

"'Fossiling' is my fun thing to do," she said. "I'm a biologist, not a paleontologist." Powell said the specimen did excite her because it is so rare; not many are found in the Carolinas.

She made a photo copy of the crab and sent it to Florida biologist Roger Portell, who is a fossil crab specialist.
Based on the photo copy, he estimated that the crab was from the Pleistocene epoch, which ranged from 10,000 to 1.6 million years ago.

It fell a little short of the earlier estimate of 3 million years, but Portell needs to get a look at the claws to diagnose the age properly, he said.

As the senior biological scientist for the Florida Museum of Natural History at the University of Florida in Gainsville, Portell has seen a lot of fossils.

He has studied a large number of crab specimens, which are fairly common in Florida's fossil record, many of them big stone crabs. He said he's studied parts of fossil crabs that are 40 million to 45 million years old.

He's eager to see the Corolla crab because its intact.

"It's unusual to find a complete specimen," Portell said. "Most of them are in bits and pieces. If it is a Pleistocene crab, they virtually haven't changed."

He also explained that this crab was probably rapidly buried in mud or sand, which encased it and allowed it to be preserved while the fossilization process slowly took over.

Since it was covered quickly, scavengers didn't have a chance to pick it apart, Portell added. The crab was more than likely buried beneath the ocean floor. But, it could have simply been buried on the beach too.

Portell theorized that the fossil came into shore after storm-charged underwater erosion uncovered it. Just from looking at the photo copy, he said he could tell the fossil had been rolling around on the bottom for a while because it was a little beat up.

No matter how old it is, Portell would like Alexander to donate it to the Florida or any other museum so it can be studied and put on display for everyone to enjoy.

The scientist explained that a lot of unique specimens are out there, but unfortunately they don't always make it into scientific institutions and often end up catching dust on someone's mantle.

"Even if it's only 10,000 years old, it's still a fossil and really neat—it's an excellent find," he said.

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