Two Student Scientists Discover a 309-Million-Year-Old Species and Name It After Their Mothers

Two young student scientists at Chicago’s Field Museum have helped identify a previously unrecognized species that lived about 309 million years ago—and gave it a deeply personal name.

Allison Sefcovic and Payton Kohlberg, who worked through the museum’s Women in Science internship program, studied a remarkably well-preserved fossil from Mazon Creek in Illinois. Their research showed that the specimen, which had previously been classified as Amphibamus grandiceps, actually represented a distinct species.

A Fossil With Remarkable Detail

The newly named species, Jeanerpeton mazonensis, was an early relative of modern amphibians. Scientists describe it as a small, squat animal that would have lived in the swampy river-delta environment of what is now Illinois.

The fossil preserves unusual details, including scales on the back, tiny bones along the belly and even impressions of the animal’s eyes. Such preservation is possible because sediments at Mazon Creek could rapidly cover plants and animals, helping preserve delicate features that normally disappear during fossilization.

A Name With a Family Connection

The species name has a special meaning for the two researchers. Both Sefcovic’s and Kohlberg’s mothers are named Jean, so the students chose Jeanerpeton, meaning “Jean’s crawler from Mazon Creek,” to honor them.

The discovery also highlights how important museum collections can be. The fossil had been found decades earlier by an amateur collector and donated to the Field Museum. It was only after the students and researchers examined it more closely that its anatomical differences became clear.

Encouraging the Next Generation of Scientists

For Sefcovic and Kohlberg, the project was more than the identification of an ancient animal. Both were participants in the Field Museum’s Women in Science program, which encourages young women to explore careers in science and museums.

Kohlberg said that before joining the research group, she knew little about paleontology. Working directly with the fossil gave her greater confidence to take on an unfamiliar scientific field.

The researchers’ study, published in the Journal of Vertebrate Paleontology, adds another piece to the story of how early four-legged animals diversified hundreds of millions of years ago.

Sources

• Field Museum — “Mother of amphibians: New species of proto-amphibian described by two student scientists, named in honor of their moms” — September 24, 2026.
• Journal of Vertebrate Paleontology — “Jeanerpeton mazonensis, gen. et sp. nov.: A new, exceptionally preserved, late Carboniferous amphibamiform from the Mazon Creek Lagerstätte, Illinois” — published online September 24, 2026.
• PEOPLE — “Students Discover a 309-Million-Year-Old Creature Was Actually a New Species, and Name It After Their Moms” — September 29, 2026.