Dig of the Week: Mosasaur Discovery in Texas

MOSASAUR FOSSIL-A Mosasaur Skull Fossil discovered in Dawson, Texas, on display at the Corpus Christi Museum of Science and History


By Carla Charter

Imagine a carnivorous ocean lizard which looked like a crocodile with flippers, could be up to 50 feet long and had the speed of a shark or whale. This creature, the Mosasaur, actually lived 85 million years ago toward the end of the cretaceous period. “It was the T-Rex of the Ocean.” according to Thomas Vance, Biology Professor at Navarro College. “We believe the flippers were an adaptation for the marine type creature. It was a foil used for stabilization and to get through the water and swim.

A partial fossil of this impressive creature was recently uncovered in Texas, the fourth such Mosasaur discovery in Navarro County. “A property owner in West Corsicana area came across it while taking a walk through his field and came across some rocks.  He was curious about the type of rock so he brought it to me at the college. It was identified as the Vertebrae of a Mosasaur., which was a this one was 25-30 feet in length if it had been complete,” Vance, who was the Mosasaur dig site director, said.

“We were not able to recover the complete skull but we did recover parts of the cranium and lower jaw.” The fossil eroded from the side of a hill. the bones all water tumbled the bones and   they were broken up and stacked. from the water current.

Also discovered were a couple of shark teeth from a small shark. “We are not sure if that was the last meal of the Mosasaur or whether the shark was a scavenger of the Mosasaur after it died,” said Vance.

So how does a sea reptile end up in Texas.  “At that point in geological history there was an inland sea from the Gulf of Mexico through Texas and the Great Plains and onto Canada toward the Arctic Ocean. These oceans raised and lowered through geological time,” Vance explained.

“We began work in the summer of 2017 and also 2018. The site was excavated by volunteers including students and members of the Dallas Paleontological Society. They are planning on reopening the site next year for several weeks to finish up the excavation,” he explained.

Once the excavation is complete the Mosasaur bones will probably be donated to Southern Methodist University to be used as a lab tool, Vance stated. More information on the Dallas paleontological Society can be found at www.dallaspaleo.org