Giant salamander fossil unearthed at Gray Fossil Site

JOHNSON CITY, Tenn. (WJHL) — Researchers at the Gray Fossil Site have discovered the remains of a giant salamander that once called prehistoric Appalachia home.
According to a news release from East Tennessee State University (ETSU), the giant plethodontid salamander was strong-jawed and possessed a powerful bite.
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The species, Dynamognathus robertsoni, was about 16 inches long, making it one of the largest salamanders to ever exist in the area.
In the present day, Northeast Tennessee and all of Southern Appalachia are teeming with a wide variety of salamanders. Among those, researchers say, are dusky salamanders, a stream-dwelling species that measures about seven inches long at their largest. Dusky salamanders are related to Red Hills salamanders, a large species that lives underground with a worm-like body and small limbs.
'Finding something that looks like a Red Hills salamander here in East Tennessee was a bit of a surprise,' Assistant Collections Manager Davis Gunnin stated in the release. 'Today, they're only found in a few counties in southern Alabama, and researchers thought of them as a highly specialized dead-end lineage not particularly relevant to the evolution of the dusky salamanders. Discovery of Dynamognathus robertsoni here in Southern Appalachia shows that these types of relatively large, burrowing salamanders were once more widespread in eastern North America and may have had a profound impact on the evolution of Appalachian salamander communities.'
Guinn described Dynamognathus robertsoni as 'the largest plethodontid salamander and one of the largest terrestrial salamanders in the world.'
Assistant Collections Manager Shay Maden said the name of the newly discovered salamander comes from its bite and also pays homage to the volunteer who found the first specimen at Gray Fossil Site.
'This group of salamanders has unusual cranial anatomy that gives them a strong bite force, so the genus name – Dynamognathus – Greek for 'powerful jaw,' is given to highlight the great size and power of the salamander compared to its living relatives,' Maden said.
As for 'robertsoni,' that name comes from Gray Fossil Site volunteer Wayne Robertson. According to ETSU, Robertson discovered the first specimen of the salamander and has sifted through more than 50 tons of soil containing fossils since 2000.
Guinn, Maden and other researchers from the Gray Fossil Site and ETSU published their findings in the journal Historical Biology. The other authors included:
Director and Professor of Geosciences Dr. Blaine Schubert
Head Curator and Associate Professor of Geosciences, Dr. Joshua Samuels
Museum Specialist Keila Bredehoeft
Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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