Angulomastacator is a type of duck-billed dinosaur that lived during the Late Cretaceous period, around 76.6 million years ago. It was discovered in the Aguja Formation found in Big Bend National Park, Texas.
The name Angulomastacator means “bend chewer.” This name refers to the unique shape of its upper jaw and the region where the dinosaur was found, known as the Big Bend area.
Scientists only have one known fossil of Angulomastacator. This fossil is a part of the upper jaw called the maxilla. What makes it special is that it has a distinct curve, unlike any other known hadrosaur dinosaur, which were typically flat. This might indicate that Angulomastacator was a unique dinosaur that evolved specifically in its environment.
Angulomastacator belonged to a group of dinosaurs known as hadrosaurids, which were herbivores. They had sets of teeth that grew in layers and could keep eating plants continuously as they chewed with them.
The first suggestion that there were Lambeosaurinae, a subgroup of hadrosaurs that Angulomastacator belongs to, in Texas was made by paleontologist Kyle Davies in 1983. A more complete specimen was found later by a research team, and it was identified and named in 2009 by Thomas Lehman and Jonathan Wagner.
The unique features of Angulomastacator suggest that the dinosaurs living in the Aguja Formation had distinct characteristics that set them apart from those in other areas, such as Alberta and Montana. This highlights the rich diversity of life that existed millions of years ago in what is now the Texas region.