Illex coindetii (Verany 1839)

Introduction

This species has the broadest distribution within the genus, being found found on both sides of the North Atlantic. It is common in the eastern North Atlantic and Mediterranean and it the target of commercial fisheries there.

Characteristics

1. Arms
   1. Hectocotylus (either left or right arm IV)
      

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      Figure. Oral view of the hectocotylus and selected suckers of I. coindetii. Upper arrows mark the divisions between the three divisions of the hectocotylus. Drawing modified from Naef (1921-23).

      1. Hectocotylus shorter than or equal to its opposite arm in length, always equal in thickness.
         
      2. Distal portion (HA3) about 25% (17-30%) of total arm length;  dorsal series starts with 1-2 proximal conical knobs followed by truncate lamellae; ventral series starts with 1-2 conical knobs followed by digitate papillae.
      3. Basal portion (HAb) about 13% (10-14%) of total arm length.
      4. Proximal portion (HA1) with 5 - 7 pairs of normal suckers increasing in size distally.
      5. Middle portion (HA2) with suckers about 1/2 diameter of proximal suckers; sucker series widely separated; conspicuous constriction between HA1 and HA2.
      6. Trabeculae distal to largest normal suckers (HA1) modified as fringed lobes.
         
         

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         Figure. Generalized diagram of an Illex hectocotylus defining the terminology used. Drawing modified from Roper, et al. (1998).
         

2. Tentacles
   
   1. Largest distal medial manal sucker-rings notched in distal half or all around.
      
      
3. Head
   1. Head-width index high, 19-26.
      
   2. Beaks: Lower beak with jaw edge long, wings long and wide, rostral width narrow, lateral wall short. Upper beak with hood long, shoulder smooth, rostrum long, wing short, jaw angle with small notch but no tooth, lateral wll short, crest curved .
      
      
4. Fins
   1. Fin angle > 50°.
      
      
5. Reproductive structures
1. Spermatophore: "Spermatophore cone at oral end of cement body, low, rounded triangle lens-shaped or diamond-shaped in outline; oral tube broad; aboral neck of cement body very short, broad, indistinct." (Roper, et al., 1998).

Distribution

Geographícal Distribution : Eastern Atlantic: 15°S to 60°N, Mediterranean and Black Sea. Western Atlantic: Caribbean Sea, Gulf of Mexico and southeast Florida; 1O°N to 27°N.

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Figure. Distribution chart of all four species of Illex; modified from Roper et al. (1998).

The squids are known to carry out diel vertical movements: they are associated with the bottom (usually muddy to silty grounds) during the day and disperse into the water column at night. They also migrate seasonally between deeper waters in winter and shallower waters in the summer.