Opisthoteuthis calypso Villanueva, Collins, Sanchez and Voss 2002

Introduction

Many reports of Opisthoteutis agassizii from the eastern Altlantic exist. Recently many of these have been shown to belong to a separate species, Opisthoteuthis calypso (Villanueva, et al., 2002).

Characteristics

1. Arms
   image info

   Figure. Oral view of Opisthoteuthis calypso paratype, mature male, 35 mm ML, from Villanueva, et al., 2002.

   1. Arms subequal.
   2. Arms I in males without increased robustness.
   3. Female: Typically 7th sucker largest.
   4. Suckers number 47-58 on each arm in adults.
   5. Males with two fields of enlarged suckers present; largest sucker diameter of distal field equal or (typically) exceeds that of proximal field.
   6. Proximal field with greatly enlarged suckers only on arms III, other arms with slightly enlarged suckers of which suckers of arms IV are most enlarged. Number of enlarged suckers 2-6 (usually 4) that lie within sucker positions 4-9 with largest usually sucker 7.
   7. Distal field with greatly enlarged suckers on all arms but sligtly larger on arms III and IV. Number of enlarged suckers 2-3 (rarely 4) that lie within sucker positions 23-29 with largest usually sucker 26.
   8. Single web nodule on ventral margin of all arms; arises opposite sucker 24-27 (males) or 22-23 (females).
   9. Cirri short; maximum length 5 mm in largest octopods.
   10. First cirrus appears between suckers 1 and 4 but usually between 1 and 2.

Comments

More details of the description of Opisthoteuthis calypso can be found here.

Opisthoteuthis calypso differs from all members of the genus (where males are known) in having greatly enlarged proximal field suckers only on arms III.

Life History

Males reach a larger size than females (Males: total length to 482 mm, weight to 5400 g. Females: total length to 342 mm, weight to 1650 g). Mature males with 15-103 (ave. - 42) sperm packets in reproductive tract. Oviducal eggs range from 5.1 to 7.5 mm.

Distribution

Type locality: 43°35'N, 02°16'W, Cantabric Sea, Bay of Biscay. Distribution: Eastern Atlantic Ocean and Mediterranean Sea (Villanueva et al., 2003). This species typically occurs on muddy bottoms at depths from 365 m (S.E. Atlantic) to 2208 m (Mediterranean Sea).

References

Villanueva, R., Collins, M., Sanchez, P. and N. Voss. 2002. Systematics, distribution and biology of the cirrate octopods of the genus Opisthoteuthis (Mollusca, Cephalopoda) in the Atlantic Ocean, with description of two new species. Bulletin of Marine Science 71(2):933-985.