Robust body; snout very short and broad; eye small, round; mouth wide, transverse, a little behind tip of snout; five long gill slits, last three over pectoral fin; two dorsal fins, first over pelvics, second and smaller fin over anal; tail fin almost symmetrical, with large lower lobe; tail base flattened, with large keel that continues forward as crest along body and over gill slits, with two more crests above along body.
Dark, with prominent white spots.
Size: 12 m (old visual records to 21 m).
Habitat: pelagic in nearshore and offshore waters.
Depth: 0-240 m.
This species is distributed worldwide in tropical and subtropical seas, including throughout the eastern Pacific.