Graceful shark

Description

Contrary to its common name,the graceful shark's spindle-shaped body has been described as "tubby".The wedge-like snout is short and pointed.The eyes are rather large and circular,and equipped with nictitating membranes (protective third eyelids).The mouth has short,indistinct furrows at the corners and contains 31–33 upper and 29–33 lower tooth rows.The upper teeth have a single narrow cusp with serrated edges,upright at the center of the jaw and becoming more oblique on the sides.The lower teeth are similar to the upper teeth,but more upright and slender.The five pairs of gill slits are fairly long.The pectoral fins are falcate (sickle-shaped) and taper to pointed tips;their leading margins measure about a fifth as long as the total length in sharks over 80 cm (31 in) long.The first dorsal fin is high and broad,with a pointed apex and a concave trailing margin;its origin lies roughly over the insertion (the rear of the fin base) of the pectoral fins.The second dorsal fin is relatively large and located about opposite the anal fin,which is about of equal size.There is no ridge between the dorsal fins.The caudal fin has a well-developed lower lobe and a ventral notch near the tip of the upper lobe.This species is bronze above and white below,which extends onto the flanks as a pale stripe.The pectoral fins,dorsal fins,lower caudal fin lobe,and sometimes the pelvic fins usually have black tips,while the upper caudal fin lobe darkens towards the trailing edge and the anal fin may be completely light.The fin markings tend to fade with age.The maximum known length is 1.7 m (5.6 ft)