Newly uncovered North Dakota fossils could stir T. rex vs. Nanotyrannus debate
Bowman area bone bed continues to yield wonders
BOWMAN, N.D. — Michael Kjelland, a hunter of dinosaur fossils, was hiking in western North Dakota about two years ago with his father, Mike Sr., prospecting for new finds when he noticed a promising patch of ground consistent with the Hell Creek Formation, a layer of geological material renowned for fossils.
Kjelland thought it would be a good spot to return to the next digging season, so he contacted the landowners and was given permission to do so.
That led to the discovery of a Triceratops skull that in turn became the subject of a Wall Street Journal documentary exploring the roles that various entities, including for-profit companies, universities, governments and nonprofit companies, play in the commercial fossil trade.
When it comes to that, Kjelland wears several hats: He is an assistant professor at Mayville State University as well as a cofounder of a nonprofit company called Fossil Excavators that focuses on the discovery and preservation of fossils, as well as on the environment and issues related to conservation.
Kjelland said the discovery and preservation part of his work came into play with the site near Bowman that produced the Triceratops skull — now known as "Skull X" — and this past summer yielded a number of additional fossils he said fall into the category of rare and significant.
This summer's finds included both adult Tyrannosaurus rex and juvenile Tyrannosaurus rex remains.
According to Kjelland, only a small number of juvenile T. rex bones have ever been found, and those were discovered in states outside of North Dakota.
Also found at the site near Bowman last summer were bones thought to be from Nanotyrannus lancensis, which some scientists say was a dwarf relative of T. rex that deserves its own species designation.
Others in the paleontology community dispute that, holding that such finds are simply juvenile examples of larger tyrannosaurid dinosaurs.
Kjelland said the discovery this past summer of a possible Nanotyrannus jawbone could bolster the case made by those who say the creature was a species separate from its much larger relatives.
He added one thing that may help settle the question is a planned CT scan of the jawbone that would hopefully detect teeth that haven't erupted yet, as jawbone tooth capacity could help clarify whether Nanotyrannus, "Nano" for short, is its own species.
The fossil discovered last summer believed to be from a Nano was given the name "Beautiful Nightmare," according to Kjelland. Whether the jawbone is from a Nanotyrannus lancensis or a juvenile T. rex, he said, it remains a big deal "because it's something that hasn't been found in North Dakota before and there are very few of these out there."
In addition to the jawbone, fossils from more than a dozen species were found last summer at the Bowman site, including:
- Triceratops (possibly parts belonging to Skull X).
- Amia (a fish).
- Borealosuchus (crocodile).
- Brachychampsa (alligator).
- Turtles (more than two species).
In addition, a femur was unearthed that is believed to have come from an Anzu wyliei, a prehistoric critter scientists nicknamed "the chicken from hell" for its size, as the birdlike creature may have weighed more than 400 lbs.
The discovery could further enhance the Anzu's already ferocious reputation, as the femur unearthed last summer is roughly twice the size of Anzu femurs that were previously found.
According to Kjelland, the latest find actually raises the question of whether the oversized femur belonged to an Anzu or a completely new species of oviraptorid dinosaur, a group of dinosaurs that had feathers and wings but could not fly.
Since removing fossils from the western North Dakota dig last summer, Kjelland has shared them with fellow dinosaur experts to get their opinions on what was found.
One of those experts was Peter Larson, president of the Black Hills Institute of Geological Research in Hill City, South Dakota, a private corporation specializing in the excavation and preparation of fossils, as well as the sale of both original fossil material and museum-quality replicas.
Larson said the haul was impressive.
"With T. rex, they've found quite a few teeth. They've found vertebrae. They've found a toe claw," Larson said, referring to some of last summer's discoveries.
When it comes to Nanotyrannus, Larson said, in addition to the upper jaw that was discovered last summer the fossil hunters also unearthed a tiny toe claw that could be from a Nanotyrannus or a juvenile T. rex.
Larson said bone beds like the one near Bowman formed in the distant past when rivers and streams carried remains downstream until the flow of water slowed because of something like a bend in the river.
At that point, bones and teeth would settle to the bottom in a concentrated area, according to Larson.
"They are digging in an old collection that was collected by an old stream channel," Larson said, referring to Kjelland and his fellow fossil hunters.
Many of the fossils Kjelland has uncovered come from the late Cretaceous period of geologic time around 66 million years ago, when it's believed an asteroid struck the earth, precipitating the widespread die-off of dinosaurs.