Familia Xiphiidae


by I. Nakamura

Large, robust fishes, with elegantly streamlined bodies, characterized by elongation of the snout (premaxillae and nasals), to form a long flattened sword (round in cross-section in billfishes, Istiophoridae). Mouth large, teeth in adults absent; no gillrakers; gill membranes united to jugular anteriorly and free from each other posteriorly. No pelvic fins or pelvic girdle; 2 dorsal fins in adults the first beginning just behind the head, short, the second very small; anal fin separate in two parts in adults; a single horizontal keel on each side of caudal peduncle, caudal fin lunate. Scales absent in adults.
Epipelagic in tropical and temperate seas, in coastal as well as offshore waters, strongly migratory (but generally not forming schools), aggressive.

Genera 1.

Recent revisions: Nakamura, Iwai and Matsubara (1968), Nakamura (1985).