Unearthing an ancient croc

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Team brings remains of 65-million-year-old marine animal to the surface at Rowan Fossil Park 

August 15, 2016

It is one of the best specimens found at the Rowan University Fossil Park in some time.

And it took some hardware store plaster, some dollar store tin foil—and a whole lot of precision and muscle—to move it from its resting place of 65 million years to a laboratory in Rowan Hall.

“This is probably the third most complete crocodile we’ve found,” Paul Ullmann, postdoctoral researcher in the University’s School of Earth & Environment, says of the remains of an ancient crocodile unearthed at the fossil park this summer.

Rowan University Fossil Park video

The specimen includes portions of the crocodile’s skull and lower jaw, plus 19 teeth.

“There’s nothing from below the head. But it’s a much bigger find than we usually make,” says Ullmann.

Transporting the specimen, found in the fossil park in Mantua Township, to a Rowan laboratory in Glassboro, where it will be painstakingly researched by University paleontologists, was a significant undertaking.

The Fossil Park, located on a 65-acre tract that was a former sea floor, contains thousands of fossils and provides researchers with the best window, east of the Mississippi, into the Cretaceous Period—the heyday of the dinosaurs.

Fossils found at the site, include, among others, marine snails, brachiopods, bryozoan colonies, shark teeth, boney fish, sea turtles, marine crocodiles and mosasaurs.

Because the floor of the fossil quarry itself sits below the water table, areas unearthed for study fill up with groundwater. In the case of the crocodile specimen, researchers pumped water out of the area every 15 minutes as they worked, according to Ullmann.

The specimen was relatively intact, which means each fossil bone was not taken from the site one by one. Instead, using dollar store tin foil and plaster from a nearby Lowe’s home improvement store, the team wrapped the skull in foil, burlap and plaster, using greensand as an additional cushion, so that it could be unearthed altogether.

“Everything came out in one giant block of plaster, sand and burlap,” says Ullmann. “We call that a jacket. It’s the largest jacket we’ve ever had to deal with here.”

Once the plaster was in place, it took a group of seven to slide the fossil on an old road sign and move it to a waiting Rowan Facilities vehicle for transportation to the Glassboro campus.

“It was a 500-pound block, over three feet long,” Ullmann says.

The process of stabilizing the fossil was akin to setting a broken bone in a cast, he notes, chuckling about the use of bargain basement materials to unearth such a significant find.

The specimen has been housed for a month in a lab in Rowan Hall. Now that the entombing sediment in the jacket is completely dry, researchers will begin examining the fossil closely. One of the things they’ll look to determine is its genus—whether it is a Thoracosaurus or a Hyposaurus, two similar looking, fish-eating crocodiles that were distantly related.

It’s unlikely, Ullmann says, that the team will find more pieces of the crocodile’s skeleton. After the specimen’s death, the skull likely sank to the bottom of the sea floor, where it has remained for 65 million years, Ullmann says.

“Right now, it’s hard to predict how much we can put back together. But it certainly will be one of our showpieces,” he says.

Southern New Jersey has been a hotbed of vertebrate paleontology since 1858, when the world’s first dinosaur skeleton was discovered in Haddonfield, says Kenneth Lacovara, lead paleontologist and director of the Rowan Fossil Park.

“Our site has produced amazing specimens since the 1920s. This new fossil is one of five extinct species of marine crocodiles that have been found in these deposits,” says Lacovara, who also is founding dean of Rowan’s new School of Earth & Environment.

In addition to using the site for research, Lacovara and his team host school groups and an annual community dig day at the site.

“When people make a personal connection with the place where they live and the earth’s ancient past, it’s a transformational experience for them,” Lacovara says. “We’re using the amazing history preserved here to teach kids about the scientific method and to help them see science as a possible pathway for their future selves.”

Rowan purchased the Fossil Park in January from the Inversand Company, which mined manganese greensand at the site for nearly a century. The University is working to develop the site into a world class center for science education and exploration.

Lacovara is world renowned for his discovery of Dreadnoughtus schrani, a massive, plant-eating dinosaur that is the best example found of any of the largest creatures ever to walk the planet.

Researchers at the park are looking to determine if the fossils found there represent a mass die off of the animals that once lived there during the Cretaceous Period. The team is analyzing the fossils, sediments and geochemistry of the site to gain a clearer picture of the period when dinosaurs roamed the earth.