The pelvic fins are much smaller than the first dorsal fin. A fin servo system positions the fins. Its dorsal and anal fins are confluent with the rudimentary caudal fin. Sand sharks have a large second dorsal fin. The logo is a white crane on a red vertical tail fin. More derived forms had a nearly vertical symmetric tail fin. Basal species had a rather asymmetric or "heterocercal" tail fin. Squadron markings usually go on the tail fin. Most species have a dorsal fin. The end of the caudal fin is concave. They have one dorsal fin located near the caudal fin. They lack the caudal fin typical of fishes. It is a substitute for shark fin soup. The second dorsal fin is smaller than the first. The peduncle of the caudal fin is thick.