Skin lesions caused by Dermophthirius penneri (Monogenea : Microbothriidae) on wild-caught blacktip sharks (Carcharhinus limbatus)

Skin lesions caused by the ectoparasite Dermophthirius penneri Benz, 1987 ( Monogenea: Microbothriidae) on 2 wild-caught blacktip sharks (Carcharhinus limbatus) from the northern Gulf of Mexico were studied using light and sca nning electron microscopy. Grossly. lesions appeared as multifocal, well-de marcated, ovoid or irregularly shaped, light gray patches of skin. Scanning electron microscopy of lesions revealed gaps between placoid scales appare ntly created by drtachment and loss of placoid scales, rotated and tilted p lacoid scales with blunt distal tips and shallow ridges, and a frayed epith elium that covered some placoid scales and filled some spaces between placo id scales. Light microscopy of lesions revealed epithelial hyperplasia acco mpanied by dermal infiltrates of moderate numbers of loosely arranged lymph ocytes interposed between collagen bundles in the superficial layers of the stratum compactum. This report provides the first details of microborhriid skin lesions on wild sharks. Our results indicate that D. penneri caused c hronic skin lesions not associated with bacterial infection or severe. debi litating, skin disease in the studied sharks.