The pelvic fin is anterior to the tail fin. Its caudal or tail fin is forked. These include logo lights, which illuminate the company logo on the tail fin. Many of these locomotory modes incorporate multiple combinations of pectoral, pelvic and tail fin movement. Squadron markings usually go on the tail fin. River dolphins have two flippers and a tail fin. The logo is a white crane on a red vertical tail fin. Later variants moved one of the top fuselage turrets aft of the tail fin. The tail fin is square in shape. When swimming, whales rely on their tail fin propel them through the water. The flippers, dorsal fin, tail fin and back are a dark grey. A novel feature is that the flight deck is built into the tail fin. Most importantly, the fossil preserves the soft tissue outline of a tail fin. The fish's body tapers down its length, ending with a large tail fin. The extensive dorsal and anal fins may merge or nearly merge with the tail fin.