North Texas dino had tough armor, keen sense of smell

A prehistoric skull found 24 years ago by a teenager in Fort Worth is now helping scientists understand the brain functions of a North Texas native. Pawpawsaurus campbelli lived 100 million years ago and was identified in 1996 by Yuong-Nam Lee, then a doctoral student at Southern Methodist University.

Lee and Louis Jacobs, a paleontologist at SMU, have co-authored a new paper that used CT imaging to study the brain of Pawpawsaurus. It's the first time we've seen inside the Pawpawsaurus skull, as few studies have been done on the endocranial anatomy -- scientist-speak for brain and skull -- of its biological family.

This North Texas dino is named for the Paw Paw Formation, a geological feature where fossils are found in Texas. It lived on the shores of an inland sea that stretched from the Gulf coast to the Arctic. Think the Narrow Sea from Game of Thrones. Dallas is somewhere around Valyria. Arizona is Dorne.

Pawpawsaurus was a herbivore with armored plates on its back and eyelids, but without the clubbed tail characteristic of its younger cousin, Ankylosaurus. It didn't have the stable vision of Ankylosaurus that helped it wield the clubbed tail. And although Pawpawsaurus had impressive sensory ability compared to its contemporaries, it was still less-evolved than Ankylosaurus.

Younger cousins always get the cool stuff, right?

Jacobs said large nostrils that look "like a trumpet bell" and wide air passages helped Pawpawsaurus smell predators, look for food or find mates.

"It's not the largest that occurs in armored dinosaurs, but it's bigger than most dinosaurs," Jacobs said.

The CT scan also showed a unique inner ear structure similar to today's crocodiles. The ear, combined with the large nasal passages, would have allowed Pawpawsaurus to amplify low frequency sounds.

"Once you can see inside the brain, that opens a whole new world," Jacobs said.