The potentials and limitations of two taxa of terrestrial snails (polygyraspp. And euglandina rosea) as a source material for the radiocarbon dating of indigenous shell mounds and middens in florida, usa

•Terrestrial gastropod shells provide a potential alternative material for radiocarbon dating on archaeological sites where preferred materials are lacking, but their accuracy for dating varies by taxon and environment.•We compare radiocarbon dating results from paired archaeological samples of reference materials with the shells of two terrestrial snail taxa—Polygyraspp. (flat coil snails) and Euglandina rosea (rosy wolf snails)—from the Cockroach Key archaeological site, in Tampa Bay, an open-water estuary on the western coast of the Florida Peninsula, USA.•In one-third of the total 12 pairings, we found no statistically significant difference at the 95% probability level; for the other pairings, differences between snail shell dates and the reference dates ranged from decades to several centuries.•The results suggest that both taxa have the potential to yield reliable radiocarbon dates, although not without complications.•Future study should be directed to the dating of snail specimens of known-age from the pre-bomb (pre-1950) or bomb peak (1969–1973) eras may be able to determine whether the shell carbonates are in isotopic equilibrium with the atmosphere.