In a remarkable discovery, two interns at Chicago’s Field Museum have identified a new species that dates back approximately 309 million years. The creature, named Jeanerpeton mazonensis, is a proto-amphibian that boasts remarkably preserved features, including impressions of its eyes, scales, and unique “belly ribs.”
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Allison Sefcovic and Payton Kohlberg, who played pivotal roles as co-lead authors of the study, decided on a personal tribute for the species’ name, drawing inspiration from their mothers, both named Jean. The full name, Jeanerpeton mazonensis, translates to “Jean’s crawler from Mazon Creek,” referencing the renowned fossil site in Illinois where the specimen was originally uncovered.
The fossil, which resembles a squat, chubby salamander or frog, was initially discovered by an amateur collector who later donated it to the Field Museum. Initially misclassified as Amphibamus grandiceps—an already well-known ancient amphibian—the true nature of this specimen was only revealed upon closer examination. The research team found sufficient distinct anatomical characteristics to classify it as its own species, as detailed in a study published in the Journal of Vertebrate Paleontology.
Misclassifications in the fossil record are not unusual; scientists occasionally group poorly understood specimens together into what is termed a “waste bin taxon.” This classification remains provisional until detailed analysis can clarify the fossils’ identities. Cam So, a postdoctoral researcher at the Field Museum and co-author of the study, explained, “Jeanerpeton is one of those species. We now have enough evidence to support it as an anatomically distinct animal.”
The fossil provides an exceptionally detailed glimpse into a creature that inhabited the earth during the Carboniferous period. Mazon Creek, at that time, was a swampy river delta, where sediment covered dead flora and fauna at a rapid pace, thus preserving intricate details that are often lost to time.
Sefcovic noted the exceptional condition of this fossil, stating, “In the fossil of Jeanerpeton, we can see some of the scales on its back and the tiny ‘belly ribs’ called gastralia. You can even see the eye impressions! It’s so cool to see.” These details are invaluable as they help scientists trace the characteristics associated with modern frogs and salamanders further back in evolutionary history.
The research project that led to this groundbreaking discovery stemmed from the Field Museum’s Women in Science internship programme, aimed at empowering young women to delve into scientific careers. Kohlberg, who had little background in paleontology prior to joining the Mann Lab at the museum, reflected on the positive impact of her experience.
She remarked, “My experience at the Field and in the Women in Science program has made me more confident in my abilities to try something new.” For Kohlberg, venturing into an unfamiliar scientific project initially felt daunting; however, the practical knowledge gained through the experience taught her that confidence can be built through perseverance and hard work.
“It is scary to take on a project when you feel like you don’t know as much as you should,” she shared, adding, “but I learned with my practical experience that it is possible to overcome that fear with hard work.”
With their successful identification of Jeanerpeton mazonensis, Sefcovic and Kohlberg not only contribute to the field of paleontology but also inspire a new generation of female scientists. Their journey reflects the potential for discovery that lies within the realm of science, where every step taken can lead to significant findings that enhance our understanding of the history of life on Earth.