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Gonatus onyx: Description continued

Tsunemi Kubodera, F. G. Hochberg, and Richard E. Young
  1. Arms
    1. Arm formula: II=III=IV>I
    2. Armature in four series: arms I-III with 2 medial series of hooks (replaced by suckers at arm tips) and 2 marginal series of suckers; arm IV with suckers only.
    3. All arm suckers with similar dentition: Ca. 12-13 pointed teeth distally grading to smooth region proximally.
    4. Suckers of medial series of arms IV largest, followed by marginal suckers of arms IV, then the marginal suckers of arms III.
    5. 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. Side and oral views of arm armature of G. onyx 69 mm GL. Left - Large hook and inner ring of a large marginal sucker of arm III. Right - Inner ring of large medial series sucker (left) and of large marginal sucker (right) of arm IV. Drawings from Young (1972).

  2. Tentacles
    1. Primary locking-apparatus with 4-6 thick ridges, each with medial sucker and alternating knobs.
    2. Largest suckers of ventral-marginal series with 10-12 teeth on distal 2/3 of inner ring; teeth are more broadly spaced than teeth on arm suckers. These suckers about same size as largest arm III suckers.
    3. 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. Side and oral views of club armature of G. onyx 69 mm GL. A - Central hook. B - Inner ring of largest sucker of ventral marginal zone. C - Inner ring of sucker from the middle of the dactylus, ventral series. D - Inner ring of a sucker taken one-fifth of the tentacle length from the base of the club.  Drawings from Young (1972).

    4. Dorsal margin of tentacular stalk with series of alternating suckers and pads along most of stalk length; distal few suckers each with additional small, thick ridge.
    5. Ventral margin of tentacular stalk with single series of suckers along most of stalk length. Number of suckers in ventral series ca. 70-115% of those in dorsal series.
  3. Measurements and counts
    Character/Station no. 7279 8117 7279 8117
    8112 7394 
    Sex - Female - - - -
    Gladius length
     59 98 55 67 72 50
    Mantle width
     15 21 12 15 17 11
    Fin Length 25 - - 25 28 -
    Fin width 42 52 38 41 37 34
    Arm length, I
     26 40 25 29 30 24
    Arm Length, II 32 47 27 36 36 27
    Arm Length, III 31 49 31 36 37 27
    Arm Length, IV
     30 47 30 35 35 26
    i/2 Arm I, sucker count*
     28 30 26 27 28 25
    i/2 Arm II, sucker count* 30 31 29 28 31 26
    i/2 Arm III, sucker count* 30 30 28 27 31 29
    i/2 Arm IV, sucker count* 35 34 34 32 35 36
    Tentacle length 41 66 44 67 66 39
    Club length 12 16 12 15 13 11
    Club sucker count
     194 181 184 174 172 171
    Stalk sucker count (SSC), dorsal series 75 45 65 66 69 61
    SSC, ventral series
     71 45 60 54 65 48
    SSC, medial region 12 3 1 1 5 2
About This Page

National Science Museum, Tokyo, Japan

F. G. Hochberg
Santa Barbara Museum of Natural History, Santa Barbara, California, USA

University of Hawaii, Honolulu, HI, USA

Page: Tree of Life Gonatus onyx: Description continued Authored by Tsunemi Kubodera, F. G. Hochberg, and Richard E. Young. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

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