A big find in Big Bend

Fossils discovered by a University of Texas graduate student in Big Bend National Park in West Texas 35 years ago are those of a new species of duck-billed dinosaur, scientists announced this week.

The findings about the fossils — now being examined at the University of Texas, where they have remained since their discovery — were published in an article in the Journal of Systematic Paleontology.

Lead author Albert Prieto-Marquez, along with Jonathan R. Wagner and Thomas Lehman, said a few physical characteristics of the fossils allowed them to determine that the dinosaur, dubbed Aquilarhinus palimentus, had been previously unknown.

Duck-billed dinosaurs, also known as hadrosaurids, were the most common herbivorous dinosaurs at the end of the Mesozoic era, which began about 252 million years ago and ended 66 million years ago. Lehman, now a Texas Tech University professor, first discovered the fossils in the 1980s, but researchers were only recently able to determine the unique attributes that identified the animal as a new species.

BE THE FIRST TO KNOW: When big news breaks, we send Breaking News emails. Click to sign up

“The bones were badly weathered and stuck together, making them impossible to study,” Big Bend National Park said in a Facebook post Monday. “Research in the 1990s revealed two arched nasal crests thought to be distinctive of the Gryposaurus genus. At that time, the peculiar lower jaw was recognized, but it wasn’t until recent analysis that researchers came to realize that the specimen was more primitive than Gryposaurus and all other saurolophid duck-billed dinosaurs.”

The name "Aquilarhinus" comes from the Latin word for eagle, "aquila," and the Greek word for nose, "rhinos." "Palimentus" is a combination of the Latin words for "shovel" and "chin."

Prieto-Marquez told the American-Statesman he believes the animal is not only an early example of duck-billed dinosaurs but also is evidence that a wide variety of variations of the dinosaur likely stemmed from a common ancestor. Researchers said that, based on the reconstructed skull lengths of about 2 feet, the animal they studied was smaller than other duck-billed dinosaurs, which scientists say ranged in size from about 10 to 40 feet in length.

“The front of the jaws meet in a U-shape to support a cupped beak used for cropping plants. The beak of some species is broader than others, but there was no evidence of a significantly different shape (and therefore likely a different feeding style) until Aquilarhinus was discovered,” the National Park Service said on Facebook. “The lower jaws of Aquilarhinus meet in a peculiar W-shape, creating a wide, flattened scoop.”

Researchers found that the dinosaur would have scooped up loose aquatic plants from marshes where the Chihuahuan Desert in northern Mexico and West Texas lies today.

Matthew Brown, director of vertebrate paleontology collections at UT's Jackson School Museum of Earth History, said the remains of Aquilarhinus palimentus are among 1.5 to 2 million fossils housed at the facility, which is the main repository for fossils found in Texas. Even before Big Bend was a national park, UT researchers sent paleontologists there to hunt for fossils. Discoveries of new species or important findings about existing species are not uncommon in the paleontology community. He said new major findings from UT are published every couple of months.

Prieto-Marquez said he plans to continue to search and study throughout Big Bend to learn more about the evolutionary journey of duck-billed dinosaurs.

“We are looking at other slices of time, other rocks,” he said. “We are identifying new hadrosaurids, new species, kind of looking at their diversity through time from 80 million years up to about 75 million years in time.”