 The large and broad pelvic fins have convex margins and originate beneath the pectoral fins . Adult males have stubby claspers . There is a single rounded dorsal fin positioned over the pelvic fins . The short and thick tail has a skin fold running along either side and terminates in a large triangular caudal fin with rounded corners , which is almost symmetrical above and below . The soft skin is completely devoid of dermal denticles . This species varies from yellowish brown to dusky brown above ; parts of the tail 's upper surface are yellowish . The underside is white to yellow with brown fin margins . It grows up to 38 cm ( 15 in ) long and 26 cm ( 10 in ) across , though individuals of this size are rare . 
