In a region of Montana known for a 1960s fossil discovery that forever altered paleontologists’ concepts of dinosaurs, Michael D’Emic may have unearthed the bones of three new species — one a mammal, another a crocodile and the third a dinosaur.
“What’s really cool about the site is we’re getting a big picture of the ecosystem,” D’Emic said in a telephone interview from his home in Stony Brook, N.Y., where he teaches anatomical sciences at Stony Brook University. “We’re finding stuff that died in a flood, and a few seasons before, all collected in one area.”
D’Emic is waiting to collect more bones from the specimens before he names or describes the new fossils.
“He doesn’t want to say anything until he knows more,” said Greg Liggett, paleontologist for the Bureau of Land Management in Billings.
In 1964 in the same region of the Bighorn Basin, south of Billings, John Ostrom of Yale University discovered the deadly curved talon of a dinosaur later named deinonychus, or “terrible claw” — a smaller, feathered version of the fierce velociraptors made popular in the movie “Jurassic Park.” Ostrom’s research into the dinosaur’s skeletal structure was the first to relate the animals more closely to birds than lizards and to defy earlier concepts of dinosaurs as slow and stupid.
“It kind of started us on the whole dinosaur revolution of the past 50 years,” Liggett said.
Liggett, who oversees the granting of permits to dig on BLM lands in his region, said the layer of rock D’Emic has targeted to chisel into is not as readily accessible in other parts of the continent.
“I’m working one of the few sites still producing a lot of material, but logistically it’s difficult,” D’Emic said.
It was in 2007 that D’Emic found his first bone within five minutes of hammering into the 103-million-year-old, 100-yard-wide flood deposit of hardened mud and sand. At the time, he was just trying to get a sample of the rock so it could be dated. Since then, D’Emic has unearthed about 300 bones from a variety of species of varying quality during five summer digs.
“Some are in bad shape, but they’re giving us an idea of the ecosystem at the time,” he said, a period before the great dinosaur extinction of 65 million years ago.
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Two overarching concepts have come to light during D’Emic’s research. First is that most of the bones are from young dinosaurs. One is a bone from an acrocanthosaurus (high-spined lizard), which was the fourth-largest meat-eating dinosaur of that period. Similar to the later and more well-known tyrannosaurus rex, acrocanthosaurus was a dinosaur that would grow to 35 feet long and weigh up to six tons. Another fossil found was from a roughly 10-year-old Sauroposeidon (earthquake god lizard), a juvenile long-necked, plant-eating dinosaur that would grow to about 80 feet as an adult.
What was unusual about these two finds, in addition to them being juveniles, is that fossils of the dinosaurs had never been found so far north before. Previous fossils from the same species were particular to Texas and Oklahoma, more than 1,000 miles to the south.
“The interesting story emerging is that the ecosystem was really homogenous from north to south,” D’Emic said.
At that time, 103 million years ago, much of Eastern Montana was flooding or underwater as the Arctic Ocean pushed southward along the eastern edge of the Rocky Mountains to eventually connect with the Gulf of Mexico.
“It was just before a period of strong sea level rise, almost the highest ever for North America,” D’Emic said. “The animals were living in a time of really dramatic sea level rise diminishing their habitat.”
The theory about the fossilized bone bed is that a flood washed the scattered remains of many dinosaurs downriver into a low floodplain, where everything was buried helter-skelter under mud and sand. The flood deposited a number of different fossils — fish, freshwater snails, clams, five types of dinosaurs and a couple of crocodiles — all densely packed together.
“So everything is a jumble,” D’Emic said. “It’s very important everything is mapped very carefully. So once we have a lot of information you can figure out which animal is which.”
Because the site is so large and chiseling into the rock takes so long, Liggett said D’Emic could work the site for many years to come — possibly his entire life — and never run out of fossils to unearth.
“I love it out there,” D’Emic said. “I’ve made good friends in the area. I’ll keep coming back as long as there are fossils.”