1. Arms
   1. Dorsal protective membranes of arms II and III greatly enlarged (ca. 2X) relative to their ventral protective membranes, and with long, well-defined trabeculae.
   2. Suckers lack distal fleshy knob (see Onychoteuthis).
      

      Figure. Oral view of proximal regions of arms II (upper) and III of W. rancureli, Hawaii, 65 mm ML, male. Photograph b R. Young.

2. Tentacular club
   1. A few marginal suckers present in subadults, presumably lost in adults.


3. Occipital region
   1. 3 occipital folds; large occipital membrane from fold 3 extends dorsally and curves to join occipital crest without forming a distict fourth fold. Olfactory organ lies at posterior end of fold no. 2.


4. Head
   1. Beaks: Descriptions can be found here: Lower beak; upper beak.
      
   2. The margins of the funnel groove are straight and define a sharply pointed V-shape.
      

      Figure. Ventral view of head and funnel of W. rancureli, Hawaii, 65 mm ML, male. Photograph by R. Young.

5. Fins
   1. Oval with large anterior lobes; not drawn-out posteriorly (see Title illustration). The apical fin-angle is approximately 180°.


6. Photophores
   1. Absent. Note, in the photograph above, that the eye which has popped outside the eyelid, has no photophores on its ventral surface.


7. Gladius
   1. Short, blunt rostrum directed perpendicular to tip of gladius.
   2. Gladius visible in dorsal mid-line except at posterior tip of mantle.
      

      Figure. Lateral view of the posterior end of the gladius of W. rancureli showing rostrum, Hawaii, 37 mm ML. Photograph by R. Young.

Comments

The above description is based on specimens captured in Hawaiian waters.

Additional features of the description can be found here.