Fossil Plants Provide Clues to Changing Environments of Tennessee’s Past | News

The Gray Fossil Site in Gray, Tennessee is famous for preserving remnants of a 5 million year old Appalachian ecosystem. Not only do these fossils include a variety of ancient animals like rhinos, mastodons, and pandas, but they also include a forest of ancient plants. And that list of plants is now a little longer thanks to a pair of recent studies identifying two extinct plant species from the Gray Fossil Site that are entirely new to science.

The last million years on Earth have been marked by dramatic climatic and environmental changes, but few fossil sites are known in the eastern United States where paleontologists can investigate this period. The Gray Fossil Site, which is overseen by the Don Sundquist Center of Excellence in Paleontology at East Tennessee State University, is one of those few, so these two new plants help to better understand how this part of the world has changed. time.

The first of the new species is named Corylopsis grisea, a member of the witch hazel family. The species name, grisea, comes from the Latin word for the color “grey”, named in honor of the gray fossil site.

Modern species of Corylopsis, commonly known as winter hazels, are shrubs and trees native to East Asia. This new species, identified from fossil seeds, thus joins a growing list of extinct plants from the Gray Fossil Site with close relatives living in modern Asia.

“In the past, the floras of the continents of the northern hemisphere were more connected than they are today,” says Dr. Elizabeth Hermsen, co-author of new studies and researcher at the Paleontological Research Institution of Ithaca. , New York. “This connection has been facilitated by a warmer global climate, land bridges in the North Atlantic and North Pacific regions, and in some regions more precipitation than today.” Over time, environmental changes led to some plants disappearing in some areas while they survived in others.

Until this study, all Corylopsis fossils from North America were over 30 million years old, so scientists thought these plants had disappeared from the continent by then. But the discovery of this new species in Gray reveals that Corylopsis hung on much longer. The warm forest environment of the gray fossil site may have been a safe haven for plants like Corylopsis, even though most of the continent has become uninhabitable for them.

The second new plant species is named Cavilignum pratchettii. In this case, the genus, Cavilignum, and the species, pratchettii, are new, making them the first extinct plant genus identified at the Gray Fossil Site.

Caviligne is a bit mysterious. It is a flowering plant, probably a shrub or woody tree, but with only fossilized endocarps (the hard center of the fruit, like the pit of a cherry) to work on, researchers are unable to identify what could be his living relatives.

“It is certainly possible that it could represent a previously unknown family of flowering plants,” says Hermsen. “However, it’s also possible that Caviligne is related to a modern plant species, but we just don’t have enough information to make the connection yet.”

The species name, pratchettii, is in honor of the late British fantasy author Sir Terry Pratchett, a decision taken by the study’s first author, Caroline Siegert of the Department of Environmental and Plant Biology at the University of Ohio.

“I’ve been a fan of his work since I was a kid and grew up alongside one of his main characters, Tiffany Aching,” says Siegert. “It felt like a fitting tribute to an incredible man who inspired me to be brave and smart with the characters he created.”

The two new plants add to a developing picture of the gray fossil site as an ancient ecosystem full of surprises. As researchers continue to study the site’s extinct plants and animals, they’re piecing together the story of how this part of the world has changed over time and how life in Appalachia has responded.