Ommastrephidae
Martina A. Compagno Roeleveld
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close boxIntroduction
Members of the Ommastrephidae are small (about 10 cm ML) to large (about 100 cm ML), muscular squids that are often the dominant large squids in oceanic and, occasionally, neritic waters. A number of species are fished commercially.
Diagnosis
An oegopsid squid ...
- with an inverted T-shaped groove in each funnel locking-apparatus.
- with a paralarva distinguished by the presence of fused tentacles.
Characteristics
Ommastrephidae (from Roeleveld, 1988):- Funnel locking-cartilage with an inverted T-shaped groove.
- Paralarvae with fused tentacles.
- Arms with biserial suckers.
- Tentacular clubs with quadraserial suckers (club dactylus with eight sucker series in Illex).
- Buccal connectives attach to dorsal borders of Arms IV.
- Distinctive, slender gladius.
- Subcutaneous, visceral and ocular photophores present.
- Suckers of dactylus of tentacular club in four series.
- Enlargement of ventral protective membrane of hectocotylus distally. Hectocotylus possesses pores or their derivatives.
- Photophores absent.
- Suckers of dactylus of tentacular club in eight series.
- Absence of protective membrane distally on hectocotylus
- Photophores absent.
- Suckers of the dactylus of tentacular club in four series.
- Trabeculae of ventral distal flange of hectocotylus thickened.
Nomenclature
A list of all nominal genera and species in the Ommastrephidae can be found here. The list includes the current status and type species of all genera, and the current status, type repository and type locality of all species and all pertinent references.
Discussion of Phylogenetic Relationships
The relationships presented here are from the phylogenetic study by Roeleveld (1988). The relationships are based on a number of different structures but rely heavily on the structure of the hectocotylus. The lack of known relationships among outgroups makes rooting of the tree difficult. Not all workers agree with the subfamial placement of genera (e.g. Nesis, 1982/7; Wormuth, et al., 1998).
Life History
All species in the Ommastrephidae have a characteristic paralarva, the rhynchoteuthion, which has tentacles fused into a long proboscis.
image info Figure. Ventral view of a rhynchoteuthion paralarva of Ommastrephes bartramii, four-day old hatchling, off Hawaii. Photograph by Y. Sakurai).
image info Figure. An 18 mm (total length) squid that was captured, photographed and subsequently released by Alberto Villari at Messina. This appears to be a young ommastrephid, perhaps Todarodes . At this stage the proboscis of the rhynchoteuthion has split into two separate tentacles.
References
Roeleveld, M. A. 1988. Generic interrelationships within the Ommastrephidae (Cephalopoda). P.277-314. In: M. R. Clarke and E. R. Trueman (eds.). The Mollusca. Vol. 12. Paleontology and Neontology of Cephalopods. Academic Press, N.Y., 355pp.
Wormuth, J. 1998 Workshop deliberations on the Ommastrephidae; a brief history of their systematics; and a review of the systematics, distribution and biology of the genera Martialia Rochebrune and Mabille, 1889, Todaropsis Girard, 1890, Dosidicus Steenstrup, 1857, Hyaloteuthis Gray, 1849, and Eucleoteuthis Berry, 1916. Smithson. Contr. Zool., No. 586:373-384..
