Ornithoteuthis antillarum Adam, 1957

Introduction

Ornithoteuthis antillarum is known from the Atlantic Oceans. It appears to be a smaller species than its Pacific and Indian Ocean congener, O. volatilis, reaching 141 mm ML.

Characteristics

1. Arms
   1. Right arm IV hectocotylized.
      
      1. Nine large basal suckers followed by 14 smaller suckers beyond which no suckers exist, only a few pedicels; distal third of arm with large flattened, triangular pedicels folded over onto the ventral border (Voss, 1957).
         
      2. Midventral surface with honeycomb-like sculpturing with 4-5 longitudinal columns of depressions, 20-25 depressions in each column (Dunning, 1998).
         
   

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   Figure. Medial-side view (top) and oral view (bottom of the hectocotylus of O. antillarum. Drawing from Voss (1957, p. 375. Fig. 2b, c).
   

   2. Sucker dentition sexually dimorphic on all arms (Voss, 1957).
      1. Female with about 8 plate-like teeth proximally with teeth becoming more numerous and pointed in mid-arm.
      2. Male with large lateral plates in mid-arm.
         
         

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         Figure. Oral view of arm suckers of O. antillarum showing sexual dimorphism. Suckers from arm III, numbers indicate sucker number from proximal end of arm. Drawings from Voss (1957, p. 375, Fig. 2e-h).
         

   3. Proximal arms II suckers with different dentition between dorsal and ventral series (Voss, 1957).
      1. Dorsal series: Suckers 1-6 with single, large, pointed tooth distally with 1 or 2 small, plate-like teeth on each side.
      2. Ventral series: Suckers 1-5 with 2 small, medial teeth distally, with 2 small, plate-like teeth on each side.
         
      

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      Figure. Oral views of proximal 5 or 6 suckers of arms II from male O. antillarum showing different dentition between dorsal and ventral sucker series. Drawings modified from Voss (1957, p. 372, Fig. 1h,g).
      
2. Tentacles (Voss, 1957)
   1. Sucker-bearing region of club about half tentacle length.
   2. Large manus suckers with about 18-20 sharp, round,  curved teeth widely separated from one another.
   3. Dactylus suckers largest in ventral series, decreasing in size to dorsal series.
      
   

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   Figure. Oral view of the tentacular club of O. antillarum. Drawing from Voss (1957, p. 375, Fig. 2d).
   

   

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   Figure. Side-oblique view of a large club sucker ring of O. antillarum. Drawing from Voss (1957, p. 375, Fig. 2i).
   
3. Head
   
   1. Beaks: Descriptions can be found here: Lower beak; upper beak.
      
      
4. Funnel
   1. Folds in foveola and side pockets not always obvious (Voss, 1957).
      
   

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   Figure. Ventral views of the funnel groove O, antillarum showing foveola and side pockets. Left - Male. Right - Female. Drawings from Voss (1957, p. 372, Fig. 1b,c).

   

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   Ornithoteuthis antillarum. © Richard E. Young

   1. Photophores
      1. Three visceral photophores: Oval, anal photophore (right arrow below); posterior intestinal photophore (middle arrow below); posterior visceral strip photophore (left arrow below).
      2. One oval, ocular photophore on the ventral surface of each eyeball.
      3. Sexual dimorphism not clear. Some photophores may be more distinct in females (see Voss, 1957).
         
      

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      Figure. Ventral view of the mantle cavity and visceral photophores of O. antillarum. Photograph by M. Vecchione.
      

      

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      Figure. Ventral views of the ocular photophore of O. antillarum. Left - Drawing from Voss (1957, p. 372, Fig. 1f). Right - Photograph by M. Vecchione.
      

   2. Measurements and count (Voss, 1957)
      

      Sex	Male	Female
      Mantle length	94	97
      Mantle width	19	19.5
      Head width	19	22.5
      Fin length	49	52
      Fin width	45	47
      Length, arm I	41	33
      arm II	49	43
      arm III	51	43
      arm IV	46	37.5
      Tentacle length	79	78
      Club length	29	26.5

Behavior

O. antillarum has been observed from submersibles feeding with its arms folded dorsally in a modified "J-posture" at a depth of 684m in the Bahamas: it can be recognized from submersibles by its long tail. A video of O. antillarum swimming can be seen here.

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Figure. In-situ side view of O. antillarum in a J-posture. ©

Life History

Based on statolith increments representing daily growth lines, O. antillarum from the tropical central-east Atlantic (off the Gulf of Guinea) reach a maximum age of 182 days indicating a life span of about 6 months in both sexes (Arkhipkin, et al. 1998). Growth curves are sigmoidal with growth decreasing at the onset of maturation; this squid appears to be a multiple spawner frequently producing egg masses of less than 1500 eggs over a period of probably 1.5-3.0  months (Arkhipkin, et al. 1998).

Mean size of mature females was 100.39 mm ML (SD = 1.60) and 88.31 for mature males (SD = 1.73); maximum size of females captured was 138 mm ML and the largest male about 120 mm ML (Arkhipkin, et al. 1998). Ripe eggs are small, ranging from 0.73-0.8 mm in maximum diameter (Arkhipkin, et al. 1998).

Distribution

Type locality: Basse-Terre (Guadelope Island), Antilles, West Indies.

Reported from tropical and subtropical waters of the North Atlantic. In the western Atlantic it is known from about 40°N to 40°S, and in he eastern Atlantic from 20°N to 25°S (Dunning, 1988). 

References

Arkhipkin, A. I., V. V. Laptikhovsky, Ch. M. Nigmatullin, A. V. Bespyatykh and S. A. Murzov. 1998. Growth, reproduction and feeding of the tropical squid Ornithoteuthis antillarum (Cephalopoda, Ommastrephidae) from the central-east Atlantic. Sci. Mar., 62: 273-288.

Dunning, M. C. 1998. A Review of the systematics, distribution, and biology of the arrow squid genera Ommastrephes Orbigny, 1835, Sthenoteuthis Verrill, 1880, and Ornithoteuthis Okada, 1927 (Cephalopoda: Ommastrephidae). Smiths. Contr. Zool., No. 586: 425-433.

Voss, G.L. 1957. Observations on Ornithoteuthis antillarum adam, 1957. An ommastrephid ssquid from the West Indies. Bulletin of Marine Science of the Gulf and Caribbean, 7(4):370-378.