Helicocranchia

1. Arms
2. Tentacles
   1. Clubs with suckers only.
   2. Tentacular stalks with two series of suckers and pads nearly to stalk base.
3. Funnel
   1. Funnel valve absent.
   2. Funnel organ: Dorsal pad with 3 slender papillae.
   3. Funnel extremely large.
4. Mantle
   1. Tubercles absent from funnel-mantle fusion.
5. Fins
   1. Fins paddle shaped.
   2. Fins insert on short rostrum-like structure of the conus of gladius which projects dorsally in advance of mantle apex (photographs). Toll (1882) suggests that the solid extension of the conus is not a true rostrum but was evolved independently for this peculiar support of the fins.
6. Photophores
   1. Single ocular photophore. (Difficult to detect in some species.)
   2. Arm-tip photophores absent.

Vernacular Names: Piglet squid

The distribution of Helicocranchia pfefferi from Hawaiian waters shows a clear pattern of ontogenetic descent with squid occurring in progressively deeper water as they get larger. Diel vertical migration does not seem to occur in this species. The dominance of nighttime captures for young stages is a result of the low sampling effort in shallow depths during the daytime and doesn't indicate the daytime absence of small squid at these depths. Figure.

In the Atlantic Lu and Clarke (1975) show a similar vertical distribution pattern for Helicocranchia pfefferi. Most captures at less than 30 mm ML were made between 100 and 200 m. Around 30 mm ML an ontogenetic descent began although their largest specimen (49 mm ML) was taken between 300 and 400 m. Presumably the size/depth trend would continue for larger individuals.

Geographical distribution

Species occur throughout the world's tropical and subtropical oceans and, in the Atlantic Ocean, in north temperate waters (Voss, 1992).

The large funnel is present in the paralarva and makes generic identification of paralarvae easy. There is a near absence of an optic stalk making the eyes nearly sessile. Figure 

With increased age and depth of occurrence, Helicocranchia, becomes reddish in color probably as they start to mature sexually. Near sexual maturity many cranchiids apparently lose their tentacles. The insitu ROV images on the right below show that loss of tentacles is, indeed, normal.