Note

Magnoteuthis magna: Description continued

Richard E. Young and Michael Vecchione
  1. Arms
    1. Arms with thick, undulating protective membranes.
    2. Large suckers may occupy mid-regions of arms (most apparent on arms II) but sucker pattern probably variable.
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Oral view of selected arm suckers of Mg. magna, 160 mm ML, immature male, showing relative size along and between arms. White numerals refer to sucker number from arm base. Photographs by R. Young.

  2. Tentacles
    1. Club length ca. 70-80% of tentacle length.
    2. Base of club long, tapers gradually.
    3. Club suckers minute (0.05 mm) with smooth inner rings.
    4. Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Oral and lateral views of the elongate basal region of the tentacular club of Mg. magna, 160 mm ML, 39°59'N, 67°20'W, as the sucker-bearing region narrows as it loops around this twisted and damaged tentacle. Photograph by R. Young

      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. The extreme proximal end of the tentacular club of Mg. magna, 111 mm ML. The sucker-bearing region has broken up into a series on small patches (groups of red dots). Proximal direction is to the left. Photograph by R. Young.

      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Oral view of the mid-region of the tentacular club of Mg. magna, 160 mm ML.  Photograph by R. Young.

    5. Tentacle not completely surrounded by suckers even at tip.
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Aboral views of the tips of the tentacular club of Mg. magna. Left - 160 mm ML. Right - 111 mm ML. Photographs by R. Young.

    6. Protective membranes present but very low.
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Aboral-lateral views of segments of the club of Mg. Magna, 111 mm ML, showing protective membrane. Left - More proximal. Right - More distal. Photographs by R. Young.

  3. Head
    1. Eyelid with anterior optic sinus.
    2. Olfactory organ on short stalk wider than sensory dome.
    Click on an image to view larger version & data in a new window
    Click on an image to view larger version & data in a new window

    Figure. Mg. magna, 111 mm ML. Left - Lateral view of eye showing optic sinus. Right - Olfactory organ. Photographs by R. Young.

  4. Funnel
    1. Funnel pocket absent.

  5. Fins (Joubin, 1920)
    1. Fin length (without tail) 66% of ML.
    2. Fin width 79% if ML (without tail); assumming a 20 mm tail the FW becomes 71% of ML
    3. Fin width 120% of fin length (without tail).

  6. Tubercules
    1. Skin tubecules absent.

  7. Photophores
    1. Photophores absent.

  8. Pigmentation
    1. Arms with dense chromatophores aborally, epithelial pigmentation orally.
    2. Head, funnel, mantle and fins with dense chromatophores.
    3. Most pigment beyond oral region in chromatophores.
    4. Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Segments of arm II of Mg. magna, 111 mm ML. Left - Aboral view showing pigmentation and keel. Right - Lateral view showing the abrupt change in pigmentation from chromatophores (aboral half) to epithelial pigment (oral half). Groove on left side of photograph is an artifact. Photograph by R. Young.

  9. Measurements
    Source Joubin, 1920 Dive 3750  13°07'S, 09°02'W  39°59'N, 67°20'W 
    Sex Unknown Imm. female  Imm. female  Imm. female 
    Mantle length 160 111  70  160 
    Mantle width 54 --  15   
    Head length 42 --  --   
    Head width 43 27  --  30 
    Eye diameter    15.8  --  22 
    Fin length (without tail) 105 
    68  43  90 
    Fin width 127 71  51  96 
    Tail length    15  18 
    Arm I, length 80 52  33  70- 
    Arm II, length 105 69  42  86 
    Arm III, length 82 58  44  73 
    Arm IV, length 172 124  100  147 
    Arm I, sucker no. 135 --  --   
    Arm II, sucker no. 120, --  --   
    Arm III, sucker no. 112 --  --   
    Arm IV, sucker no. 109 --  --   
    Tentacle length 480 200  300  265 
    Club length 390 157  202  200 

Comments

The color of most of the photographs above have been artificially changed slightly and lightened to see details. Actual color is very deep, bright red.

About This Page


University of Hawaii, Honolulu, HI, USA


National Museum of Natural History, Washington, D. C. , USA

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