ALBUQUERQUE, N.M. — New Mexico is home to a new dinosaur species. Not only that, but the discovery is changing the timeline of when dinosaurs were walking around North America.

“This is a discovery literally decades in the making,” said Dr. Anthony Fiorillo, New Mexico Museum of Natural History and Science executive director.

A fossil found in southwestern New Mexico is part of the skull of a new species of Tyrannosaurus rex.

“This confirmed this is a new species and I was excited to actually invite other researchers and continue this project on a larger scale,” said Sebastian Dolman, lead author on the project.

Several scientists over decades have studied it and revealed their findings Thursday morning.

“This fossil was originally found by members of the public, it wasn’t found by scientists of paleontologists like me and these were people that lived in Las Cruces who were boating on Elephant Butte reservoir,” said Dr. Spencer Lucus, co-author of the project. “This was in 1983. They landed on the eastern shore of the lake and a big chunk of this jaw here was laying on the ground.”

The species is called Tyrannosaurus mcraeensis and predates any other T. rex specimen in the world by about five million years – making Tyrannosaurus mcraeensis an older cousin to the T. rex we all know.

“But it turns out in the years since we’ve – not just us – but we’ve found volcanic ash beds in the rocks that have this fossil, and we were able to get numerical ages and with those numerical ages now, we can be pretty sure that the fossil is 72 to 73 million years old,” Lucus said.

An artist’s rendition shows what the dinosaur may have looked like – standing at 40 feet tall and 12 feet long. Scientists say the differences are small, like slight variations in the jaw bones, but it’s enough to make New Mexico home to an important dinosaur discovery.

“Science is a process. With each new discovery, it forces us to go back and test and challenge what we thought we knew,” Fiorillo said.

The public can go see the fossil on display at the New Mexico Museum of Natural History and Science.