A University of Wisconsin-Parkside professor is part of an excavation in the heart of the Dallas-Fort Worth metroplex that has yielded a treasure trove of fossils dating from 96 million years ago.

Biological sciences associate professor Chris Noto is the lead author on the project, where paleontologists have partnered with a dedicated team of local volunteers on the Texas project.

Now, a new species discovered at the site is being named in honor of one of the citizen scientists, Arthur Sahlstein.

Dubbed the Arlington Archosaur Site, the area is undergoing rapid residential development, and paleontologists have been working with local volunteers and fossil enthusiasts to excavate the site over the last decade.

“The AAS wouldn’t be the success that it is if it weren’t for the small army of dedicated volunteers donating their time, energy, expertise and resources,” Noto said. “It is only fitting that we honor one of our most valuable and prolific members.”

Sahlstein co-discovered the Arlington Archosaur Site in 2003 and brought it to the attention of paleontologists. He has remained a fixture at the site ever since, discovering numerous fossils including an unusual jaw from a small crocodyliform (a distant crocodile relative), now named Scolomastax sahlsteini.

“The discovery of the site 16 years ago was a watershed moment that launched an amazing period of personal and academic discovery,” Sahlstein said. “I am very humbled to have this ‘Little Nipper’ carry my name. This partnership will be a model for future major excavations.”

Second new species

This isn’t the first time the team has named a new species for one of the site volunteers. In 2017, another new crocodyliform, this one a 20-foot-long top predator, was named Deltasuchus motherali after Austin Motheral, who was just 15 years old when he uncovered the fossils that would eventually bear his name.

The name Scolomastax means “pointed jaw” in Greek, referring to its tapered, V-shaped mandible. The 1- to 2-meter long new species is named in the current issue of the journal Anatomical Record.

“People sometimes think that crocs haven’t changed much since the age of dinosaurs, but that just isn’t true,” said paper co-author Stephanie Drumheller-Horton, from the Department of Earth and Planetary Sciences at the University of Tennessee.

“This little croc has several weird features that make us think it ate hard prey items and maybe even plants. We don’t have anything like it alive in the world today.”

But Scolomastax is important in other ways, too.

“This new species belongs to an extinct group of crocs called paralligatorids”, said Alan Turner, an associate professor at Stony Brook University and a co-author on the study.

“They have an extensive fossil record during the Cretaceous period in Asia but remain less well-known in North American deposits. Scolomastax is important in part for expanding our knowledge of this intriguing group.”

Former inland sea

The landscape where Scolomastax lived also differed greatly from modern day.

In the mid-Cretaceous, the heart of North America was covered in a shallow inland sea, cutting the continent in two. The Arlington Archosaur Site represents a rare assemblage from the eastern land mass, known as Appalachia.

It would have appeared not unlike the Mississippi River delta 96 million years ago, with warm, swampy conditions and a variety of organisms living across land and water.

Scolomastax and several other species of crocodyliform would have lived side by side with a diverse assemblage of dinosaurs, turtles, amphibians, mammals, fish, invertebrates and plants, several of which are also new species awaiting description.

Work at the site is supported in part by the National Geographic Society, who provided a grant to complete field work at the site, and the Perot Museum of Nature and Science in Dallas, which curates all the fossils found at the site and organizes the many volunteers who work there.

Currently excavations at the AAS are on hiatus as the research team works on describing the thousands of specimens that have already been discovered.

“The site has not ceased to give up its secrets,” Sahlstein said.

This project was also featured in National Geographic.

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