'Shovel-Billed' Dinosaur Roamed Texas 80 Million Years Ago | Paleontology

Aquilarhinus Palimentus Illustration

Aquilarhinus Palimentus Illustration

While sounding unusual, duck-billed dinosaurs - also known as hadrosaurids - were actually the most common herbivorous dinosaurs at the end of the Mesozoic Era.

The Aquilarhinus have lower jaws that meet in an odd W-shape that creates a wide, flattened scoop.

Some species have broader beaks, but until the Aquilarhinus was found, there was no evidence that showef hadrosaurids had beaks that varied in shape. Their front jaws meet in a U-shape to support a cupped beak they used to crop plants.

Aquilarhinus palimentus lived approximately 80 million years ago in what is now Texas.

However, it was not until this recent research - published to the Journal of Systematic Palaeontology - that researchers discovered the specimen was more ancient than Gryposaurus and the two major groups of duck-billed dinosaurs.

They were analyzed by paleontologists from Texas Tech University and the Institut Català de Paleontologia Miquel Crusafont, Barcelona, Spain.

"Its existence adds another piece of evidence to the growing hypothesis, still up in the air, that the group began in the southeastern area of the U.S", he said.

The jaw and characteristics of Aquilarhinus do not fit with those of the main group of duck-billed dinosaurs.

It became fossilised after dying and having some of its bones moved downstream by a water current and becoming lodged in vegetation. Then, over millions of years, the remains were covered in silt, fossilizing the bones in a type of sedimentary rock known as ironstone. The fact it is older suggests there might have been a greater number of lineages than previously recognised, and that they evolved before the great radiation that gave rise to the bewildering array of unadorned, solid and hollow-crested forms.

The main group of hadrosaurids called Saurolophidae commonly sported a bony cranial crests of varying shapes and sizes, but the Aquilarhinus, which is more primitive than the Saurolophidae, had a simpler a bony crest shaped like a humped nose. Researchers state that this discovery of crest in hadrosaurids further reinforce the hypothesis that the majority of the crests have a common ancestor with a simple humped nose.

Researchers are examining the fossils at the University of Texas at Austin.

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