Panopeus herbstii, also known as the black-fingered mud crab, black-clawed mud crab, Atlantic mud crab or sometimes common mud crab, is a species of true crab, belonging to the infraorder Brachyura, and is the largest of the mud crabs. Panopeus herbstii are found along the western edges of the Atlantic Ocean in areas of North America, Central, and South America. Typically Panopeus herbstii feed on molluscs such as clams. Their conservation status is not marked but they are at risk due to habitat destruction and climate change along with ocean acidification.