The Status and Distribution of the Devil Crayfish, Lacunicambarus diogenes (Decapoda: Cambaridae) in Pennsylvania

Lacunicambarus diogenes (Devil Crayfish) is perhaps the most imperiled crayfish in Pennsylvania. Despite its broad distribution across the Atlantic Coastal Plain, Devil Crayfish have only been collected on 2 occasions in Pennsylvania over the past century, both in the heavily urbanized southeastern portion of the state within the Philadelphia metropolitan area. This urban development led to the presumed extirpation of Devil Crayfish in Pennsylvania until a 2017 collection of 5 specimens from a single population in Neshaminy State Park was reported. Despite this rediscovery, the status of the species in Pennsylvania remained unknown, pending a thorough survey targeting the species. Herein, we report the results of a survey for Devil Crayfish throughout southeastern Pennsylvania. From 2021–2024, we surveyed 105 sites but found just 2 individuals: 1 at the original 2017 rediscovery site and another at Croydon Woods Nature Preserve. Both locations also harbored invasive Procambarus clarkii (Red Swamp Crayfish) from nearby burrows. Further, we conducted a land-use analysis incorporating historical records from Pennsylvania, New Jersey, and the Washington, DC, area, which revealed that even in urbanized settings, Devil Crayfish persists primarily in forested and wetland habitats, underscoring the importance of conserving greenspaces in urbanized regions. Our findings suggest a dire outlook for Devil Crayfish in Pennsylvania, highlighting the urgent need for conservation action.