A newly identified amphibian species dating back 309 million years has been named Jeanerpeton mazonensis, honoring the mothers of its discoverers, both named Jean. The fossil was found in the region now known as Chicago, in sediment deposits from the Mazon Creek fossil site.

Student paleontologists Allison Sefcovic and Payton Kohlberg uncovered the specimen, which exhibits characteristics comparable to a salamander with a squat, frog-like body structure. Jeanerpeton mazonensis lived well before the era of the dinosaurs and is considered an ancestor of modern amphibians.

The species name translates to "Jean’s crawler from Mazon Creek," highlighting both the personal connection behind the naming and the geological context. Mazon Creek is notable for its exceptional preservation of prehistoric life, capturing fine details of organisms that inhabited a swampy river delta. In this case, the fossil shows evidence of scales on the back and belly ribs, as well as delicate features such as toe pads and body outlines, providing important insights into the anatomy of early amphibians.

The specimen was initially donated to the Field Museum in Chicago, where it was briefly examined but misclassified before being reanalyzed by Sefcovic and Kohlberg. Their work has brought renewed attention to the fossil, clarifying its place in the evolutionary record.

Jeanerpeton's discovery helps fill gaps in the understanding of amphibian evolution during the late Carboniferous period and underscores the scientific value of the Mazon Creek fossil beds, which continue to yield unique and informative specimens that illuminate the biodiversity of prehistoric ecosystems.