Opisthoteuthis chathamensis: Description Continued

1. Suckers
   1. Suckers with well-developed muscualr suction pad and wall ring; small simple aperature (drawings on right).
   

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   Figure. Suckers of O. chathamensis cut in half in various planes: sucker no. 6 (left) and sucker no. 26 (right). Drawings from O'Shea, 1999.

2. Eyes
   1. Large.
      
      
3. Funnel
   1. Funnel organ V-shaped.
      
      
4. Fins
   1. Fins long, 53-64% of ML
   2. Fins without anterior lobe.
      
      
5. Gills
   1. 6-8 primary lamellae, innermost and outermost reduced insize.
   2. Lamellae 3-5 on outer demibranch with common afferent vessel at base.
      
      
6. Optic lobe
   1. Optic lobe kidney shaped.
   2. 2-5 optic bundles arise from optic lobe.
   

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   Figure. Optic lobe, white body and optic stalks of O. chathamensis. Drawing from O'Shea, 1999.

7. Digestive system
   1. Radula absent.
   2. Salivary glands absent.
   3. Digestive tract with bilobed digestive gland.
   4. Intestine about 1.5 times length of oesophagus.
   

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   Figure. Digestive tract of O. chathamensis. Drawings from O'Shea, 1999.

8. Beaks
   1. Upper beak (left) with strong lateral-wall fold.
   2. Lower beak (right) with two weak lateral-wall folds.
   

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   Figure. Side views of upper (left) and lower (right) beaks of O. chathamensis. Drawings from O'Shea, 1999.

9. Male reproductive system
   1. Accessory gland 1 dominates accessory gland complex..
   2. Penis well developed.
   

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   Figure. Male reproductive system of O. chathamensis. Photograph from O'Shea, 1999.

10. Female reproductive system
    1. Proximal portion of oviducal gland about half size of distal portion.
    2. Distal oviduct short.
    

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    Figure. Female reproductive system of O. chathamensis. Drawing from O'Shea, 1999.

11. Shell
    1. U-shape.
    2. Solid.
    3. Saddle with single outer groove, convex inner margins.
    4. Wings short, taper to acute points.
    5. Muscle insertion points marked by two small prominences.
    

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    Figure. Shell of O. chathamensis, full view (above), view of wing (below), male, 42 mm ML. Drawings from O'Shea, 1999.

12. Pigmentation
    1. Areolar spots on dorsal surfaces of mantle, head and all arm bases; mature animals with 7-10 spots on head and each arm I, 5-7 spots on head and each arm II, 3-5 spots on each arm III and 1-5 spots on each arm IV.
    2. Oral surface of arms and web deep maroon, suckers paler, cream colored.
    3. Dorsal surfaces of head and arms purplish-red.
    4. Ventral surface of mantle, dorsal surfaces of fins, orbit, web margin and tips of arms free from web paler, translucent to cream colored.
       
       
13. Measurements
    1. Measurements and counts can be found here.

References

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