Well beyond "endangered" are dinosaurs. And dinosaur finds in New Jersey may be even more rare.
Mosasaurs (from Latin Mosa meaning the 'Meuse river', and Greek sauros meaning 'lizard') are large extinct marine lizards. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs are now considered to be the closest relatives of snakes, and were varanoids closely related to terrestrial monitor lizards. They probably evolved from semi-aquatic aigialosaurs, which were more similar in appearance to modern-day monitor lizards, in the Early Cretaceous.
So, it's exciting that the assistant curator of natural history at the New Jersey State Museum has found one as part of a paleontological expedition working a site at Inversand [in Mantua] recently.
Although they have been undisturbed for 65 million years, Jason Schein is rushing to get his hands on the fossilized skeletons of sea-dwelling animals and dinosaurs from the depths of a marl pit here.
Schein’s fear is that, if he waits a day, the opportunity to excavate skeletons from the site may disappear forever.
Inversand’s manganese greensand pit in the township — the company has long asked that the exact location not be disclosed — is the last known site of its kind in South Jersey.
“In South Jersey in the late 1800s and early 1900s, there were dozens and dozens of these pits,” Schein explained as he took a break from the triple-digit heat on Thursday.
How do you think towns such as Marlton and Marlboro got their names, he asked.
The paleontologists who would dig in the pits hung out in Philadelphia, sharing finds and stories.
“Some of the most famous stories in the history of science got started here,” Schein observed.
Farmers had no use for the skeletons found in the pits.
“They originally dug it up as fertilizer,” he said of marl. Inversand markets the material that it digs from the pit here as a municipal and industrial water treatment.
Marl was also the right material to preserve the skeletons of what was trapped inside.
This week’s dig, financed with $1,500 from the Delaware Valley Paleontological Society and involving scientists from the state museum in Trenton, Drexel University and the Academy of Natural Sciences, has yielded “lots of good stuff.”
Wednesday, the team “took out of the ground the entire top shell of a big sea turtle.” The shell, Schein said, is “three feet across.”
More importantly, it is both “very well preserved” and “almost 100-percent complete.”
Thursday, the ground yielded the brain case of a mosasaur — a giant swimming komodo dragon.
“If there was ever a real life sea monster, this was it,” Schein suggested.
Sixty-five million years ago, South Jersey was a shallow sea home to fish, sharks, birds, sea turtles, crocodiles and mosasaurs.
The skeletons are headed first to Drexel and eventually to the state museum for study and possible display.
Such sites in the past have yielded the first substantially complete dinosaur skeleton — known as Hadrosaurus foukii. That skeleton was unearthed in Haddonfield and turned over to the Academy of Natural Sciences.
Mosasaur fossil found in Mantua Township marl pit | via NJ.com