A telltale jaw fragment unearthed from a 75 million-year-old rock formation in Big Bend, Texas, has led to the identification of a new dinosaur species, Leptorhynchos gaddisi.
The species is a feathered dinosaur about the size of a turkey with a bird-like, toothless beak, part of a group called Caenagnathids. Nicholas Longrich, the Yale University paleontologist who helped make the identification, said that the differences that set apart this species—named Leptorhynchos for its little jaw—were subtle.
The new species had a narrow jaw and a rounded chin, and Longrich said although the differences are slight from fossils found excavated further north, they clearly indicated this was a new species. Beak shape in birds, such as finches or albatrosses, are indicators of separate species biologically fine-tuned to take advantage of different food sources. Longrich can’t tell what kind of plant this dinosaur would have eaten from the jaw fragment.
The fossils were unearthed by a team of Texas fossil collectors; Longrich helped them make sense of the find, and they reported the new species in the Bulletin of the Peabody Museum of Natural History. By extrapolating from other closely-related species, Longrich, the son of an art teacher, also made a careful rendering of the new species. Related fossils indicated the creature would have had feathers, but been unable to fly, for example. But Longrich admits that he’s taking an educated guess when deciding how to draw some specific characteristics, such as how long its shins were.
Small dinosaurs are a particular interest of Longrich, who said they are often overlooked, and provide a view of the broad spectrum of animals that existed during prehistoric times. He took the discovery of the new species as an excuse to reevaluate the number of species in the group.
Longrich said that he thinks there is more diversity that’s yet to be described. While he was going a collection of turtle beak specimens recently, he found one that he thinks was misclassified, and is in fact another Caenagathid.
“I was trying to figure out if there was an interesting project to be done on turtle beaks, and because I’d just done this paper, I had the image of these animals fresh in my mind, so when I ran across one of these things I instantly knew what it was,” Longrich said.
That work will be described in an upcoming paper.