Spiny butterfly ray

Description

The spiny butterfly ray has a very broad,lozenge-shaped pectoral fin disk much wider than it is long,with concave front margins and abruptly rounded corners.The snout is short and blunt.The teeth have high,conical cusps,numbering 98–138 rows in the upper jaw and 78–110 rows in the lower jaw.In both jaws there are 10–12 functional tooth rows with each dental band occupying 70% the width of the jaw.There is a tentacle-like structure on the inner posterior margin of each spiracle.The tail is short and slender,measuring a quarter the disk width,with upper and lower fin folds.There are one or more serrated spines at the base of the tail. The skin is naked in juveniles and subadults,while adults develop a patch of denticles on the center of the disk.The coloration is dark brown above,sometimes with small lighter or darker spots and blotches in a marbled pattern,and white below.Juveniles have pale crossbars on the tail.The maximum reported size is 2.2 m (7 ft 3 in) disk width in the northwest Atlantic,though there are unsubstantiated reports of rays over 4 m (13 ft) off West Africa.The maximum published weight is 60 kg (130 lb)