Mantle narrow, conical, tapering into thin tail. Head wider than mantle. Fin heart-shaped, tapering posteriorly, its length more than 50% ML. Six-seven pairs of large tentacular suckers, rings without especially enlarged teeth. Carpal group of suckers short. Fixing apparatus weakly developed, without knobs. Funnel pit with foveola with longitudinal skin ridges and weakly developed side pockets.
Photophores in mantle cavity: one round near anus (large), one oval near beginning of gut (small), and one narrow strip of luminous tissue from the latter to very end of the body. One elongate photophore on ventral side of eyeball. ML up to 30 cm.
Larvae: proboscis short, 1/4-1/2 (rarely to 3/4) ML, thick, longer than arms in very early larvae, then equal or shorter. Two lateral suckers on tip are up to 2 times larger than others. Proboscis beginning to split early, at ML approx. 4-4.5 mm, finishing at approx. 5-6 mm. Arms of 3rd and 4th pairs beginning to develop at ML approx. 1.5 and 2.5-3 mm. Anterior (anal) gut photophore yellowish, developed at ML 3-3.5 mm, posterior photophore whitish and developed at approx. 8 mm, eyeball photophores at ML 4-4.5 mm, visceral luminous strip in juveniles >30 mm. Larval mantle with many large brown chromatophores. Early larvae may wholly retract into mantle.
Two close species, distinguishable only by adult males: a tropical Atlantic Ornithoteuthis antillarum and its Indo-Pacific counterpart Ornithoteuthis volatilis (Sasaki, 1915). Both reported off Namibia (O. antillarum by Laptikhovsky, 1989; O. volatilis by Villanueva and Sánchez, 1993). These nerito-oceanic species live mostly in midwater over the slope and seamounts (or not far from these), and near the bottom.