Paleontologists have described a previously unrecognized genus and species of hadrosaurid dinosaur from a partial bone found in Texas, the United States.

Life restoration of Aquilarhinus palimentus, a hadrosaurid dinosaur from the Aguja Formation. Image credit: David Breguet / CC BY-SA 4.0.

The newly-identified dinosaur species roamed our planet during the Campanian age of the Late Cretaceous epoch, between 75 and 72 million years ago.

Scientifically named Malefica deckerti, the ancient creature was around 5 m (16 feet) in length.

It belonged to Hadrosauridae, a large family of plant-eating dinosaurs common in the Late Cretaceous of Europe, Asia, and North America.

Popularly known as duck-billed dinosaurs, they received their name from their broad, flattened, elongated snouts and their toothless beaks.

“Hadrosaurid dinosaurs were among the most diverse and widespread large terrestrial herbivores of the Late Cretaceous, with nearly 65 species recovered from every Mesozoic continental landmass except Australia, Madagascar, and the Indian sub-continent,” said Universitat Autònoma de Barcelona paleontologist Albert Prieto-Marquez and his colleague Jonathan Wagner.

“These animals possessed complex, interlocking dental batteries optimized for chewing, hypertrophied nasal passages and a wide variety of supracranial crests.”

Their phylogenetic analysis placed Malefica deckerti within the Hadrosauridae family but outside the major hadrosaurid group Saurolophidae.

“Much is known about phylogenetic relationships and character evolution among Saurolophidae, a clade generally identified as ‘derived’ hadrosaurids,” the paleontologists said.

“Much less is known of the diversity and evolution of the early-diverging branches of Hadrosauridae, the outgroups to Saurolophidae.”

The partial left maxilla of Malefica deckerti was found in the Aguja Formation near Bruja Canyon in Big Bend National Park, southwestern Texas, the United States.

“Malefica deckerti is the third hadrosaur named from the Aguja Formation,” the researchers said.

“The species is represented solely by a relatively well-preserved but incomplete isolated left maxilla.”

“The maxilla is the structural keystone of the hadrosaurid facial skeleton, and often expresses morphology specific to genera, sometimes to species.”

The discovery of Malefica deckerti contributes to a better understanding of the evolutionary transition between outgroup non-hadrosaurid hadrosauroids and saurolophid hadrosaurids.

“The recognition of Malefica deckerti adds to our growing understanding of the diversity of taxa at the ‘base’ of the hadrosaurid tree,” the scientists said.

“Although the material is fragmentary, the new species from Texas indicates that basally-branching hadrosaurids were also distributed in southern Laramidia, in addition to Appalachia and Eurasia, evidencing the widespread occurrence of these early hadrosaurid lineages in the northern hemisphere spanning the uppermost Santonian through the Upper Maastrichtian.”

“It was from this grade that the great diversity of Saurolophidae evolved, and with this new species we can better trace the evolution of the features of the saurolophid radiation.”

Source: sci.news