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.
Ommastrephid squids are among the strongest swimmers in the Cephalopoda. Some are commonly known as "flying squid" due to their ability to glide over the ocean surface as seen in the photographs.
Figure. A squid, presumably Ommastrephes bartramii, gliding over the sea surface near Japan. Left - The original photograph by Geoff Jones. Right - Enlarged and enhanced (by Geoff Jones) reproduction of the squid. Note the spread fins and the spread arms with extended membranes that apparently aid gliding. © Geoff Jones
An oegopsid squid ...
- with an inverted T-shaped funnel/mantle locking-apparatus.
- with fused tentacles in paralarvae.
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.
- Funnel/mantle locking-apparatus with an inverted T-shape.
Figure. Frontal views of the funnel/mantle locking apparatus. Left - Funnel component of Illex illecebrosus. Middle - Mantle component of Illex illecebrosus. Photographs by M. Vecchione. Right - Opened mantle cavity showing the funnel/mantle locking apparatus of Todaropsis eblanae. Drawing from Naef (1921-23).
- Funnel adductor muscles
- Thick lateral funnel-adductor muscles connect lateral edges of funnel with head near its ventral surface. [These muscles are not homologous with the more superficial muscles of the Sepioidea which bear the same name.]
- Paralarvae (rhynchoteuthion stage) with fused tentacles (=proboscis).
The proboscis begins to split at the base usually around 3-4 mm ML. The split gradually increases until the proboscis has split completely in half to form the two tentacles at about 7-10 mm ML. The proboscis increases in size as the paralarva grows but at about 6 mm ML the proboscis begins to shrink in absolute size until the tentacles are formed. The small newly formed tentacles appear to be initially non-functional (poorly formed suckers) but grow rapidly (see Wakabayashi et al., 2002).
- 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 with primary conus.
Figure. Ventral view of the gladius of Todarodes sagittatus, immature, 120 mm ML. Drawing from Naef (1921-23).
Comparison of subfamilies:
|Photophores present1||Dactylus suckers||Funnel- groove foveola3||Funnel- groove side pockets3||Distal protective membranes on hectocotylus||Carpal locking apparatus2|
|Ommastrephinae||Yes||4 series||Yes||Yes||Ventral membrane enlarged subdistally||Present except Ornithoteuthis|
|Todarodinae||No||4 series||Yes/No||No||Ventral membrane with thickened trabeculae||Absent|
- MASDEA (1997).
Evolution and Systematics
Discussion of Phylogenetic Relationships
Although the family is very well characterized, placement of species with genera and subfamilies has, in some cases, been controversial. These controversies have often revolved around the importance of absence of a character (e. g., absence of foveola and side pockets from the funnel groove of Todaropsis, a feature shared with Illex) which, without adequate polarization, could be interpreted as a synapomorphy, a symplesiomorphy, or a convergent loss.
Figure. Phylogenetic tree of the Ommastrephidae. The three basal branches represent the three subfamilies. Figure based on Roeleveld (1988).
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). The latter authors place Todaropsis next to Illex in the Illicinae.
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:215
Specimens with Barcodes:204
Species With Barcodes:21
- Subfamily Illicinae
- Subfamily Ommastrephinae
- Genus Dosidicus
- Genus Eucleoteuthis
- Genus Hyaloteuthis
- Genus Ommastrephes
- Genus Ornithoteuthis
- Genus Sthenoteuthis
- Subfamily Todarodinae
- Genus Martialia
- Genus Nototodarus
- Genus Todarodes
- Genus Todaropsis
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