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Onykia (Onykia) robsoni (Adam, 1962)

Michael Vecchione, Richard E. Young, and Kotaro Tsuchiya
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Containing group: Onykia

Introduction

Adults of O. robsoni reach a length of 470 mm ML. This species apparently has the broadest distribution of any member of the genus.

Diagnosis

An Onykia ...

Characteristics

  1. Tentacles
    1. Club with 13-16 pairs of hooks.
      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 tentacular clubs of O. robsoni, 260 mm ML. Photograph by D. Stevens.

      Scanning electron micrographs of the hooks can be found here.

  2. Head
    1. Beaks: Descriptions can be found here: Lower beak; upper beak.

  3. Mantle
    1. Covered with fleshy, irregular warts.
      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. Ventral view of the mantle of O. robsoni showing skin warts. Photograph by D. Stevens.

  4. Fins
    1. Sagittate shape.
    2. Length 53-62% of ML at 156-370 mm ML.
    3. Width 51-70% of ML at 156-370 mm ML.

  5. Gladius
    1. Rostrum ventral length 23-36% of GL; triangular in cross-section.

Comments

The above data is from Kubodera et al., 1998. This species is very similar to O. robusta in the shape of the fins but is separated by the structure of the skin (i.e., warts vs ridges), and the fewer pairs of club hooks (13-16 vs 16-18).

Additional features of the description are found here.

Nomenclature

Onykia aequatorialis (Thiele, 1920) was described from the equatorial Atlantic at 18°07'W. Kubodera, et al., 1998, examined a spent female of O. robsoni from Bermuda that was very similar to O. aequatorialis which caused them to question the validity of the latter. Since the holotype has been lost and there are no distinguishing features in the type description, they designated O. aequatorialis a nomen dubium.

Life History

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Figure. Ventral view of a young O. robsoni, 260 mm ML. Photograph by D. Stevens.

 

Distribution

The type locality is off Angola at 16° 36'S, 11°20'E. This species occurs north of the southern subtropical convergence, off southwestern Australia, New Zealand and southern Africa and it is indistinguishable from specimens taken from the Gulf of Mexico and off Bermuda in the North Atlantic (Kubodera, et al., 1998). It is also reported off the southwestern coast of South America.

Other Names for Onykia (Onykia) robsoni (Adam, 1962)

References

Adam, W. 1962. Cephalopodes de l’Archipel du Cap-Vert, de l’Angola et du Mozambique. Memorias da Junta de Investigacoes do Ultramar, series 2, 33: 9-64.

T. Kubodera, U. Piatkowski, T. Okutani and M.R. Clarke. 1998. Taxonomy and Zoogeography of the Family Onychoteuthidae (Cephalopoda: Oegopsida). Smithsonian Contributions to Zoology, No. 586: 277-291.

Title Illustrations
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Scientific Name Onykia robsoni
Reference Kubodera, T., U. Piatkowski, T. Okutani and M.R. Clarke. 1998. Taxonomy and Zoogeography of the Family Onychoteuthidae (Cephalopoda: Oegopsida). Smithsonian Contributions to Zoology, No. 586: 277-291.
View Dorsal
Scientific Name Onykia (Onykia) robsoni
Location S.W. Chatham Rise near New Zealand at 4421'S, 17532'E
Comments Caught in bottom trawl at 685-700 m depth.
Acknowledgements National Institute of Water & Atmospheric Research (NIWA)
Specimen Condition Fresh
Identified By Darren Stevens
Sex Female
Life Cycle Stage Mature
View Dorsolateral
Size 885 mm ML, 11100 g weight
Collector NIWA
Image Use creative commons This media file is licensed under the Creative Commons Attribution License - Version 3.0.
Copyright ©
About This Page


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


University of Hawaii, Honolulu, HI, USA


Tokyo University of Fisheries, Tokyo, Japan

Page: Tree of Life Onykia (Onykia) robsoni (Adam, 1962). Authored by Michael Vecchione, Richard E. Young, and Kotaro Tsuchiya. 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.

Citing this page:

Vecchione, Michael, Richard E. Young, and Kotaro Tsuchiya. 2011. Onykia (Onykia) robsoni (Adam, 1962). Version 20 March 2011 (under construction). http://tolweb.org/Onykia_%28Onykia%29_robsoni/19975/2011.03.20 in The Tree of Life Web Project, http://tolweb.org/

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