Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis

Mink Frogs (Rana septentrionalis) are a unique ranid species restricted to Canada and the northern edge of the United States, from northern Minnesota to northern Maine. They are a member of the Aquarana clade that includes Green Frogs (R. clamitans), American Bullfrogs (R. catesbeiana), and four other species. Despite being relatively common where present, the biology of this species has been poorly studied and little in particular is known about its breeding and development from fertilization through overwintering as larvae. Critically, the species' representation in museum collections is limited in general, but particularly at early life stages. Here we report on our initial efforts to describe larval Mink Frog development by inducing breeding of wild-caught adults in the laboratory, then sampling tadpoles from fertilization until the subsequent spring. Specimens, including tissue samples, adult specimens of both sexes, an entire laboratory-induced egg mass, and a captive-bred larval series are available in the Yale Peabody Museum of Natural History. Our approach here demonstrates that Mink Frogs can be captive bred for use in laboratory experiments, and our work provides a novel larval series from egg mass to metamorphosis for this secretive, understudied species.