Larvae are known as Doratopsis sagitta Chun, 1908. This species is usually cited as the only member of a separate family, Grimalditeuthidae, but belongs to Chiroteuthidae according to Young (1992) because larvae are chiroteuthid-like. Mantle narrow-conical, soft, gelatinous, transparent, tapering into long tail. Fin round or transverse-oval. Behind it another fin located on conus of gladius, approximately equal in length but heart-shaped; broken off in most subadult and adult specimens. Head long and narrow. Funnel in adult squids fused with mantle, head not fused with it in nuchal region. Arms long, thin, subequal in length, with 2 rows of suckers except at very ends. Sucker stalks grow out of centre of thick three-topped tubercle. One elongate dark photophore on end of each arm. Tentacles present only in larvae, then resorbing, usually only stalk bases remaining in juveniles, lacking in adults. Gladius very thin, with long conus. ML up to 23 cm.
Larvae transparent, with long "snout" (arm-crown pillar) and even much longer septate neck. Transverse line of dark chromatophores on ventral side of snout immediately ahead of eyes. Fins petaloid. Funnel not fused with mantle. Funnel cartilage bottle-shaped, mantle cartilage nose-like. Arms 1st-3rd very short, 4th pair much longer than others. Third arm developed later than 1st-2nd, at ML approx. 4-5 mm, but soon (at approx. 15 mm) becoming equal to 2nd. Tentacles well developed, club short, keeled, with 4 rows of suckers (2 in very early larvae); suckers on distal part of stalk in 3 diagonal rows. Transition to juvenile stage occurring at ML approx. 10-15 mm, but fusion of funnel to mantle and disappearance of tentacles occurring much later, between 20 and 40 mm (without second fin).