When Neurides Martins wiped the sediment off the tiny tooth, she knew she had found something special.
This tooth was the first piece of a new dinosaur species and an unusual one. About the size of a Great Dane, about 90 million years ago, the carnivore would have been walking two legs upright in the desert, resting its weight on just one long toe, the middle toe of three.
Nearly 50 years ago paleontologists found mysterious footprints in the area, but so far no one knew what creature they had made. While his three functioning toes make the new species a theropod dinosaur, such as Tyrannosaurus Rex because of this rare anatomy, it essentially functions as if it were a monodactyl or one-toe adaptation still common in Brazil was not recorded dinosaurs.
Named Vespersaurus paranaensis for the city and state in which it was found. The dinosaur is also the first in the Paraná region of Brazil and the most complete and best preserved theropod dinosaur ever found in Brazil. Martins and colleagues described the dinosaur and its environment on June 26 in the journal Scientific Reports .
Finding a Foot
At less than an inch in length, this first tooth was easily overlooked, but Martins, historian and director of the Brazilian Paleontological Museum in Cruzeiro do Oeste, believed that the 440-pound block from rock and dirt in which she had found the tooth contained more. A month later, Martins discovered the unusual foot of the dinosaur, which confirmed its unique way of moving and hunting.
"I was very happy, very excited," says Martins.
Vespersaurus paranaensis is a member of the Noasaurinae group of theropod dinosaurs. It measured about 5.2 feet in length and stood at about 2.6 feet high. It was considered a small, dinosaur living in the desert and had pneumatic bones ̵
With a length of about six inches, his foot was critical to understanding the new species. The two toes flanking the middle toe had large, knife-like claws that were probably used to catch and cut prey, possibly lizards and pterosaurs.
For Luiz Eduardo Anelli, a paleontologist who was not involved in the discovery or description of the Vespersaurus paranaensis it is the feet of the dinosaur that make it such a fascinating find. For real monodactyls, he says, the extra toes were lost in the course of evolution, as in horses and old kangaroos .
"The kangaroo became a monodactyl to jump while the horse was able to enlarge his toes. Agility and speed, which make it easier to escape predators and to travel long distances," he says for the same reasons as possible explanations for the new dinosaurs that also run on toe.
"Monodactyly reveals so much, including the anatomical diversity of these animals, that reflects their different ways of life," he says. "Dinosaurs made adjustments to dig caverns, glide, climb, swim, fish, open furrows in the ground for their eggs, run, fly. They were extraordinary animals. "
While Brazil had already confirmed some 40 million years ago that some 40 different dinosaur species roamed the country, the southern state of Paraná, where the museum is located in a city of only 20,000 people had never made such a discovery. The paleontological excavation site in Cruzeiro do Oeste had already discovered other types of fossils, including bones of a Gueragama sulamericana lizard and several individuals of the pterosaur species Caiuajara dobruskii first concrete indication that a dinosaur got a foothold here.
And with 40 percent of the entire skeleton, the Vespersaurus paranaensis expert has already delivered an extraordinary amount of new information. For Martins, however, the discovery is just the beginning.
"We could still find more new species – which I expect and imagine – and more information, more details about our dinosaur," she says. "We still have much to learn, even if we only look at the same block. We were able to describe our dinosaur and confirm that it is a unique species in the world, but that does not mean we're done. Our work continues. "