Opisthoteuthis mero: Description Continued

1. Suckers
   1. Suckers with simple sucker aperatures (drawing on right).
   

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   Figure. Suckers of O. mero, cut longitudinally, sucker from proximal field (left), sucker from distal field (right). Drawings from O'Shea (1999).

2. Eyes
   1. Large.
3. Funnel
   1. Funnel organ V-shaped.
4. Fins
   1. Anterior lobes apparently absent in preserved specimens.
5. Gill
   1. Gills with 7 (rarely 6) lamellae.
   2. Lamellae 3 and 4 with common afferent vessel at base.
      
      
6. Optic lobes and nerves
   1. Optic lobe kidney-shaped.
   2. 3-5 optic nerve bundles pass through/by white body.
   

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   Figure. Optic lobe, white body and optic bundles of O. mero, female, 37 mm ML. Drawing from O'Shea (1999).

7. Digestive system
   1. Radula absent.
   2. Digestive gland bilobate.
   3. One pair of large salivary glands on buccal mass.
   4. Intestine about twice esophagus length.
   

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   Figure. Side view of digestive tract of O. mero, male, 35 mm ML. Drawing from O'Shea (1999).

8. Beaks
   1. Upper beak without teeth; with weak lateral wall fold.
   2. Lower beak with two weak lateral wall folds.
   

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   Figure. Side views of upper beak (left) and lower beak (right) of O. mero. Drawings from O'Shea (1999).

9. Male reproductive system
   1. Spermatophore glands complex and accessory-gland complex nearly equal in size.
   2. Accessory gland 3 dominates accessory-gland complex.
   3. Penis poorly developed (triangular, lappet-like).
   

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   Figure. Male reproductive tract of O. mero, 45 mm ML. Drawings from O'Shea (1999).

10. Female reproductive system
    1. Large ovarian eggs 7.2 x 4.9 mm.
    2. Proximal oviduct about 3 times longer than distal oviduct.
    

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    Figure. Female reproductive system of O. mero, 76 mm ML. Drawings from O'Shea (1999).

11. Shell
    1. Shell solid.
    2. Saddle with outer surface concave and inner surface convex.
    3. Fin insertion area marked by 2 well-developed shoulder blades.
    

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    Figure. Shell dorsal (top) and posterior views (bottom) of O. mero. Drawings from O'Shea (1999).

12. Pigmentation
    1. Areolar spots on dorsal surfaces of mantle, head and all arm bases; 6-11 spots on head and each arm I, 6-12 spots on head and each arm II, 6-9 spots on each arm III and IV.
    2. Areolar spots larger and fewer in juveniles.
    3. Dorsal surfaces red to light purple.
    4. Margin of eye, outer margins of fins and cirri, pale white.
    5. Oral surfaces of arms and web darker purplish-red; distal surfaces fade to pink.
    6. Suckers and sucker aperatures, pale yellow.
       
       
13. Measurements
    1. Measurements and counts can be found here.

Comments

The above description is taken from O'Shea, 1999.

References

O'Shea, Steve. 1999. The Marine Fauna of New Zealand: Octopoda (Mollusca: Cephalopoda). NIWA Biodiversity Memoir 112: 280pp.