With two red dorsal fin crests up to 1 meter high and ribbon-like silvery body up to 8 meters in length. Distinguished by the dorsal fin rays until end of abdomen fewer than 82; abdominal vertebrae 34 to 37; in complete adult specimens, total vertebrae count, 113 to 122 and total dorsal fin rays, 333 to 371; total gill rakers on first gill arch in large fish, 47 to 60; in adults, anteriormost part of dorsal fin with 2 crests: first dorsal fin crest with 3 to 6 rays united by fin membranes and second dorsal fin crest with a single elongated and ornamented ray and not united by membrane to other dorsal fin rays (Ref. 92949). Other diagnostic characters: pelvic fin with a single elongated ray and with more than 3 membranous appendages; caudal fin small, reduced (Ref. 41299). Cristophore (new term) present and supports the first dorsal fin crest; pelvic fin with a single permanent, extremely elongate and ornamented ray; 11-14 pectoral-fin rays, with a horizontally-oriented base, allowing the fin to be vertically-oriented when adpressed against the body; all large fish lacking a caudal fin, but in the young, principal rays number 3-4 (usually 4), may be extremely elongate, and the tip rarely with ornament; lacking procurrent rays; highly elongate body, with no anal fin; total dorsal fin rays in complete specimens (significantly less in individuals of approx. max. TL of 1.5 m), 3 33 to 449 and total vertebrae 113 to 163; approx. max. length of largest specimens, 8 m (all autotomized); stomach characterized with an elongate postabdominal caecum extending to end of body; muscle masses compartmentalized by a complex system of connected intermuscular septa; with up to three dorsal horizontal septa and three ventral horizontal septa in addition to the horizontal, vertical, and transverse septa common to most teleosts; as a result of autotomy, the posterior part of the adult body (including most large juveniles) terminating in a healed-over stump or terminus (new term); still, many specimens found with fresh (with a ragged appearance very different from a healed termini) incomplete self-amputations of the posterior part of the body, notably not consistent with shark bites. Toothless jaws or with only some tiny vestigial teeth (Ref. 92949).