(Rüppell, 1844)
Mantle narrow, cup-like, with acute tail. Fins in larvae and juveniles tongue-shaped or oval, in adults semicircular, not joined and not reaching mantle end. Arms rather long and very strong, all pairs, incl. 4th, bear hooks in 2 rows, almost to tips. Tentacles long, thin; club elongated, not widened, in larvae with 1 row of large and 3 of small suckers; in adults with 1 central row of 3-5 hooks and 2 rows of suckers (suckers of ventral row located between hooks). Gladius caudally narrowed into acute needle.
Photophores: 10 in the mantle cavity (2 large near anus; 3 closely spaced at level of brachial hearts; 2 on sides near gill bases; 2, next to each other, at the level of stomach; and 1 very small ventrally on the conus of gladius); 12 on ventral and caudal parts of the eyeball (small and large, of different structure, located in strict order, some large ones with green metallic glitter); 6 or 7 under skin on tentacular stem. Photophores in mantle cavity begin to develop at ML approx. 5 mm, all developed at ML 20 mm. First eye photophores appearing in early larvae (ML 2-3 mm). Their distribution, as well as the semicircular fins, acute tail end, and 2 rows of suckers/hooks on 4th arms, are characteristic for larvae and juveniles. In freshly caught larvae 2 pink patches: at base of tentacle and at base of club. Egg size 1.0-1.3 mm. ML up to 5 cm.
This species represented by series of local forms of subspecific, or may be even specific rank: Pyroteuthis addolux Young, 1972, and Pyroteuthis serrata Riddell, 1985.