Often found in bulk-bagging aisles of grocery stores. One of the largest archignathids, P. gigantis was at first considered to be a species complex, but the various oral groove sizes are currently being split into different taxons. The oral groove depth for P. gigantis is measured at 15 mm. Recently, specimens have been observed attached to bags holding catfish, and bags holding robotic kitty-litter machines, signaling a dramatic shift in life habits.