Pectoral fin of the megamouth shark, <i>Megachasma pelagios</i> (OCA-P 20110301).

<p>(<b>A</b>) External morphology of the ventral (left) and dorsal (right) surfaces of the pectoral fin. White boxes represent the sites used for sampling of skin tissues for histological studies. (<b>B</b>) Skeletal structure of the ventral side of the pectoral fin (left) and the dorsal side of the basal cartilages (right). ms, mesopterygium; mt, metapterygium; pt, protopterygium; rd, radial.