‘Significant’ 94M-year-old marine reptile fossil found in Utah

KANAB, Utah — A set of fossils found in southern Utah over a decade ago is now believed to be the oldest mosasaur fossil ever uncovered in North America, and it’s helping paleontologists better understand the evolution of the marine reptile that once existed in the age of the dinosaurs.

The fossils were discovered in Glen Canyon National Recreation Area near its border with the Grand Staircase-Escalante National Monument all the way back in March 2012, according to the Bureau of Land Management.

Scott Richardson, a trained volunteer at the time, was helping University of North Florida paleontologist Barry Albright look for fossils of underwater creatures from the late Cretaceous Period at the time. That’s when Richardson came across multiple small skull fragments and vertebrae on a shale slope.

Teams from the Bureau of Land Management and National Park Service joined in the effort, helping unearth almost half of the fossil specimen over the next two field seasons. What they did recover they brought back to the bureau’s Kanab lab for review.

They were able to quickly determine that they had uncovered a large mosasaur fossil from about 94 million years ago. Mosasaurs were underwater reptiles that existed up until about 66 million years ago, according to Encyclopedia Britannica.

But with the help of Michael Polcyn, a paleontologist at Southern Methodist University, the team was able to confirm the fossils discovered near Lake Powell are the oldest of their kind ever found on the continent. Their findings were published in Cretaceous Research this month.

“Mosasaurs from younger rocks are relatively abundant, but mosasaurs are extremely rare in rocks older than about 90 million years. Finding one that preserves so much informative data, especially one of this age, is truly a significant discovery,” said Alan Titus, a paleontologist for the Bureau of Land Management, and the co-author of a study, in a statement Friday.

The finding could help researchers better understand how the species evolved with time.

The researchers point out that mosasaurs were descendants of Komodo dragon-like land creatures before growing fins and shark-like tails that helped them dominate in the water. These early mosasaurs started out at about 3 to 5 feet in length, but some eventually evolved into behemoths exceeding 50 feet.

As part of the study, researchers used micro-CT scans and computer reconstruction models to help show how the creature improved blood supply to the brain as it evolved over time. Polcyn explained that the adjustments they saw is something similar to what was known about the evolution of whales.

“(The finding) sheds light on long-standing questions regarding the relationship of some early-branching mosasaurid species,” he said in a statement. “But (it) also provides new insights into the evolution and antiquity of a novel cranial blood supply seen in a particular group of mosasaurs.”

Several researchers from across the globe also participated in the study.