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Two new species of ancient moles identified at the Gray Fossil Site
The Gray Fossil Site in Gray, Tennessee preserves a one-of-a-kind ancient ecosystem nearly five million years old. Many scientific studies have explored the larger fossil animals at the site, including rhinos, alligators, and red pandas, but recently there has been increased focus on the tiny creatures.
A new study published in the journal Palaeontologia Electronica is the first to analyze the fossil moles of the Gray Site. By comparing fossil bones and teeth with other living and extinct mole species, the researchers identified four different types of extinct moles, including two species that are entirely new to science.
The research was conducted by Danielle Oberg, doctoral student at the University of Arkansas and alumnus of ETSU’s paleontology Master’s program, and Dr. Joshua Samuels, associate professor in the ETSU Department of Geosciences and curator at the Gray Fossil Site & Museum.
“Mole species are usually tied to environmental conditions and soil types,” says Oberg. “This many species at one site is quite special.”
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A fossil humerus (upper arm bone) of the new mole species, Parascalops grayensis. Mole arm bones are specially adapted for their digging lifestyles and can be very useful in distinguishing species. Scale bar: 2mm. Image by Josh Samuels.
Moles are excellent diggers and voracious predators, contributing to their ecosystems by aerating the soil and feeding on tiny animals. The moles identified in this study represent a variety of lifestyles from digging to swimming, revealing a unique and diverse ancient community.
The two new species identified in this study are Parascalops grayensis, a relative of the hairy-tailed moles that still dig through the soil of East Tennessee today, and Magnatalpa fumamons, a relative of modern-day desmans, which are aquatic predators found today only in Europe and Asia. This is the oldest known record of hairy-tailed moles in the world and the first known record of desmans in eastern North America.
The other two moles the researchers identified, Neurotrichus and Mioscalops, have also never been found in this part of the world before, and both lived more generalized lifestyles. Modern-day Neurotrichus (also called shrew-moles) are adept at digging, swimming, and climbing. Altogether, this ancient mole community includes a combination of species and lifestyles unlike anywhere else.
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The lower jaw of a fossil shrew-mole, Neurotrichus. These teeth are well-suited for eating insects and other small creatures. Scale bar: 1mm. Image by Josh Samuels.
“We have four different moles at the Gray Fossil Site, and the lifestyles of those moles are very different,” says Samuels. “This discovery helps improve our understanding of small predators living here in the Appalachian region about five million years ago.”
Many of these mole bones and teeth are less than a centimeter in length. They were recovered thanks to the Gray Fossil Site & Museum’s policy to screenwash all excavated sediments from the site and to the efforts of the many volunteers and students who sort through the ancient sediment to extract tiny fossils.
“It feels amazing to describe and name a new species, and I got to do it twice in one paper,” says Oberg. “I am excited for the dedicated team of wet-screeners and pickers to find even more material for us to publish on.”
Oberg and Samuels 2022. Fossil moles from the Gray Fossil Site, TN: Implications for diversification and evolution of North American Talpidae. Palaeontologia Electronica. https://doi.org/10.26879/1150
