A new "evil spirit" buck-toothed dinosaur recently unearthed in New Mexico represents an evolutionary link between the world's oldest known carnivorous dinosaurs and later meat-loving dino species from the Jurassic, according to new research.
The dinosaur, named Daemonosaurus chauliodus (evil spirit buck-toothed reptile), is described in the latest issue of the Proceedings of the Royal Society B.
The dinosaur lived about 205 million years ago in what is now Ghost Ranch, N.M., which inspired the animal's spooky name. During the Late Triassic, this site was a dinosaur paradise with warm weather and seasonal rainfalls. The other animals there at the time, such as the predatory Coelophysis bauri dinosaur, could not have missed Daemonosaurus' distinctive "grin."
"Daemonosaurus has an unusually short snout with few teeth in the upper jaw and those projecting large front teeth in the upper jaw," lead author Hans-Dieter Sues told Discovery News, adding that the dinosaur probably measured about four to five feet in length.
Sues, curator of vertebrate paleontology at the Smithsonian's National Museum of Natural History, and his colleagues discovered the dinosaur's remains, which consist of a fossilized skull and neck.
The scientists' analysis of the remains determined that the dinosaur was part old-school Triassic with some more advanced features associated with later Jurassic dinosaurs.
The more Triassic-linked features of Daemonosaurus include its small opening in the snout between the nostril and the eye socket. It also showed more primitive bones related to the air sacs of a bird-like lung system. These later became more developed in dinosaurs.
Evil Spirit's specialized teeth, however, reveal that it was a more advanced dinosaur than its earlier relatives. As time went on, carnivorous dinosaurs, like the famous Tyrannosaurus rex, evolved longer snouts with even more teeth, complex openings in the snout, and limbs that were more bird-like.
The oldest known dinosaurs walked or ran on their hind legs and included early predatory species like Herrerasaurus. They existed in what are now Argentina and Brazil approximately 230 million years ago. Due to a gap in the fossil record, some paleontologists doubted these early dinosaurs were bipedal carnivores, but Daemonosaurus strengthens the argument that they were theropods and helps to fill in the evolutionary gap.
Although the weather was good for dinosaurs in Late Triassic New Mexico, the new findings suggest this place was very much a dino-eat-dino world.
"Daemonosaurus probably preyed on, and was preyed upon, by the more advanced Coelophysis," Sues said. "In addition, there were large non-dinosaurian predators, including a large early crocodylian relative and a large phytosaur."
Randall Irmis, curator of paleontology at the University of Utah, told Discovery News, "This discovery is exciting for several reasons. First, paleontologists had long thought that the only dinosaur species preserved in the Coelophysis Quarry was Coelophysis bauri itself; this is the first conclusive evidence of other dinosaurs from this world-famous deposit."
"Secondly," he added, "as the authors state, Daimonosaurus is important because it preserves characters that bridge the gap between very basal and early theropods such as Herrerasaurus and Eoraptor, and later theropods such as Tawa and Coelophysis."
All of the paleontologists are puzzled by Evil Spirit's "unusual" skull shape and teeth, which they say are unique among meat-loving dinosaurs. Future research may reveal what ecological roll these distinctive traits may have played during Daimonosaurus' lifetime.
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