 The common stingray has been reported to reach a width of 1 @.@ 4 m ( 4 @.@ 6 ft ) and a length of 2 @.@ 5 m ( 8 @.@ 2 ft ) , though a width of 45 cm ( 18 in ) is more typical . The flattened pectoral fin disc is diamond @-@ shaped and slightly wider than it is long , with narrowly rounded outer corners . The leading margins of the disc are almost straight and converge on a pointed , slightly protruding snout ; the trailing margins of the disc are convex . The eyes are smaller than the spiracles ( paired respiratory openings ) , which are placed closely behind . There are 28 – 38 upper tooth rows and 28 – 43 lower tooth rows ; the teeth are small and blunt , and arranged into flattened surfaces . There are five papillae ( nipple @-@ like structures ) across the floor of the mouth . 
