Scientists named the 300-million-year-old Fedexia strieglei as a gesture of thanks to the FedEx shipping company, which owns the land where the fossils were found, said study co-author Dave Berman of the Carnegie Museum of Natural History in Pittsburgh.
The 2-foot-long (0.6-meter-long) creature is also named for University of Pittsburgh geology student Adam Streigel, who mistook fossils of Fedexia's teeth for ancient fern leaves when he picked them up on a 2004 field trip.
A later excavation found two vertebrae and a well-preserved skull that clearly shows Fedexia's taste for meat: The animal had two large canine-like teeth at the front of its mouth as well as tusks anchored to the roof of its mouth, which helped the amphibian dismember prey.
"It's obvious when he bit down on something, he could really hold on to it," Berman said. "It would provide a crushing blow to the animal."
"FedEx" Fossil Amphibian Among First Landlubbers
Fedexia likely hunted smaller amphibians and 5-inch-long (13-centimeter-long) giant cockroaches that scuttled through the steamy coal swamps of the late Pennsylvanian period, 318 to 299 million years ago.
At the time, what's now Pennsylvania was practically on the Equator, said Berman, whose research appears today in the journal Annals of Carnegie Museum.
The world was also shifting toward a drier state. Glaciers were expanding, tying up moisture; sea levels were dropping; and drier, high-elevation environments were expanding.
For many water-dependent amphibian species, the brief episode of climate change meant sink or swim.
But the fossils show that Fedexia had adapted to become one of the first successful vertebrate landlubbers, Berman said. (Related: "Oldest Land-Walker Tracks Found—Pushes Back Evolution.")
For instance, Fedexia had tough, pebbly skin like that of modern-day newts (see a picture of a warty newt).
This would have prevented the Pittsburgh amphibian from drying out and from sustaining injuries such as cuts and scratches, Berman said, allowing the animal to live for longer periods on land.
Though dinosaurs stole the limelight when they came along 70 million years later, the new find is one reason the Age of Amphibians—as the Pennsylvanian period is also called—should be just as interesting to people, especially those living in the eastern U.S., Berman added.
"Here's what was inhabiting areas right out your back door."