 The fins ( especially the dorsal , pectoral , and pelvics ) of the sicklefin lemon shark are more falcate ( sickle @-@ shaped ) than those of the otherwise very similar American lemon shark . The first dorsal fin is positioned closer to the pelvic than the pectoral fins . The second dorsal fin , nearly equal to the first in size , is located over or slightly forward of the anal fin . No ridge is seen between the dorsal fins . The pectoral fins are long and broad , originating below the space between the third and fourth gill slits . The anal fin has a strong notch in the rear margin . The precaudal pit ( a cavity just forward of the caudal fin ) is oriented longitudinally . The large dermal denticles are overlapping and bear three to five horizontal ridges each . The coloration is a plain yellowish brown or gray above and lighter below , with more yellow on the fins . This species attains a maximum known length of 3 @.@ 8 m ( 12 ft ) , though it typically does not exceed 3 @.@ 1 m ( 10 ft ) . 
