Discovery of Cambarus sp. C (Decapoda: Astacidea: Cambaridae) in New Jersey and Extreme Eastern Pennsylvania

Cambarus sp. C is a poorly understood group of morphologically similar crayfishes whose range extends along North America's Atlantic Slope from South Carolina northward to Pennsylvania. In Pennsylvania, C. sp. C occurs in the lower Delaware River basin west of Philadelphia but has never been found to the east of the city. In October 2024, during ongoing surveys of eastern Pennsylvania, we discovered C. sp. C in tributaries of the lower Delaware River east of Philadelphia. One of the tributaries flows into the river from Pennsylvania (Bucks County), while 2 others flow into the river from New Jersey (Mercer County). Herein, we describe these collections, which expand the range of C. sp. C by ∼45 km to the east and add a new crayfish species to New Jersey and possibly Pennsylvania, improving our understanding of the crayfish fauna of the mid-Atlantic region of North America.