Abstract
We investigated the use of the pelvic fins for locomotion along the bottom in the little skate, Leucoraja erinacea by video recording locomotor behavior of skates both in the field and in captivity and by examining various anatomical preparations of their pelvic fins. An external notch or concavity in the lateral margin of the pelvic fins partially separates each fin into anterior and posterior lobes. The skeletal elements and musculature of the anterior lobe are highly modified and comprise a functionally distinct appendage (the crus) that possesses three flexible joints. Locomotion of skates along the bottom is almost always due to the exclusive activity of the crura of the pelvic fins pushing off the substrate synchronously to generate thrust. The skate then glides through the water a short distance as the crura are repositioned for the next thrust phase. This type of thrust and glide locomotion is called punting. We conclude that punting is a significant form of locomotion suited to the benthic lifestyle of skates.