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Illex oxygonius Roper, Lu & Mangold 1969

Michael Vecchione, Clyde F. E. Roper, and Richard E. Young
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Containing group: Illicinae

Introduction

Illex oxygonius has the most restricted distribution of the four Illex species. Since its distribution includes a region of overlap between I. illecebrosus and I. coindetii, the possibility exists that I. onygonius could represent a hybrid of these two species (Roper, et al., 1998).

Characteristics

  1. Arms
    1. Normal (non-hectocotylized) arms
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      Figure. Oral view of arm III of I. oxygonius, holotype, 207 mm ML. Drawing from Roper, et al. (1969).

       

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

      Figure. Oral view of large arm-sucker-rings of I. oxygonius, hologype, 207 mm ML.  Drawing from Roper, et al. (1969).

    2. Hectocotylus (either left or right arm IV)
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        Figure. Oral view of the distal end of the hectocotylus of I. oxygonius, holotype, 207 mm ML. Drawing from Roper, et al. (1969).

      1. Hectocotylized arm longer and more robust than opposite arm in fully mature animals.
      2. Distal hectocotylized portion of arm IV (HA3) moderately long, about 29% (24%-32%) of total arm length; 3 knobs and 2 slightly flattened papillae proximal to well-developed lamellae in dorsal row.
      3. Basal portion (HAb) of hectocotylized arm 4% of total arm length.
      4. Proximal portion (HA1) with 7 pairs of normal suckers.
      5. Middle portion (HA2) with sucker diameters reduced in size by about 1/4 on both rows; oral surface of arm constricted slightly between HA1 and HA2, but with no distinct reduction of arm musculature between normal and reduced sucker areas; rows normally separated; trabeculae not modified as fringed lobes.
      6. 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. Generalized diagram of an Illex hectocotylus defining the terminology used. Drawing modified from Roper, et al., 1998.

  2. Tentacles
    1. Club-sucker rings of largest distal medial manal suckers smooth, without crenulations or notches.
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      Click on an image to view larger version & data in a new window

      Figure. Oral view of the tentacular club of I. oxygonius, holotype, 2007 mm ML.  Drawing from Roper, et al. (1969).

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

      Figure. Oral view of a  sucker ring of a large, medial manal sucker from the midregion of the tentacular club of I. oxygonius, holotype, 207 mm ML. Drawing from Roper, et al. (1969).

  3. Head
    1. Head-width index high, 20.7 (19-23) in mature males, 17.8.
    2. Beaks: Descriptions and photographs can be found here: Lower beak; upper beak.
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      Figure. Side view of the upper (left) and lower beak (right) of I. oxygonius, paratype, 205 mm ML, male.  Drawing from Roper, et al. (1969).

  4. Funnel
    1. Funnel/mantle locking-apparatus
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      Figure. Frontal views of the funnel (left) and mantle components (right) of the funnel/mantle locking-apparatus of I. oxygonius, holotype, 207 mm ML. Drawing from Roper, et al. (1969).

  5. Gladius:
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    Click on an image to view larger version & data in a new window

    Figure. Ventral view of the gladius of I. oxygonius, paratype, 176 mm ML, male. Drawing from Roper, et al. (1969).

  6. Fins
    1. "Fin angle in mature males acute, 25°-35°, occasionally 40°; fin width equal to fin length" Roper, et al., (1998)
      .
  7. Reproductive structures
    1. Spermatophore: "Spermatophore cone at oral end of cement body, funnel-shaped, with sides equal, broadly triangular in outline; oral tube relatively broad; aboral neck moderately short, narrow" (Roper, et al., (1998).
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      Click on an image to view larger version & data in a new window

      Figure. View of a spermatophore (center) of I. oxygonius showing an enlargement of the oral end (top) and the central region (bottom). Drawing from Roper, et al. (1969).

    Life History

    Spawning grounds, season, eggs, and paralarvae are unknown at present. Food is also unknown, but presumed to be crustaceans and fishes.

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    Figure. Ventral view of the cut-open mantle cavity of I. oxygonius. The nidamental glands are very large. White spermatangia are attached to the mantle walls and near an oviduct opening. Photograph by M. Vecchione.

    Distribution

    Type locality - Western North Atlantic off Key West, Florida at 24°13'N, 81°58'W.

    Geographical distribution. I. oxygonius is found only in the western North Atlantic from off New Jersey (about 40°N) south to the Straits of Florida and the Gulf of Mexico but limits not well defined (Roper et al., 1998).

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

    Figure. Distribution chart of all four species of Illex; modified from Roper et al. (1998).

    Vertical distribution. Found over shelf and upper slope waters at depths of 50-555m (Roper et al., 1998).

    References

    Roper, C.F.E., C.C. Lu, and K. Mangold. 1969. A New Species of Illex from the Western Atlantic and Distributional Aspects of Other Illex Species (Cephalopoda: Oegopsida). Proceedings of the Biological Society of Washington, 82:295-322.

    Roper, C.F.E., C. C. Lu, and M. Vecchione. 1998. Systematics and distribution of Illex species; a revision (Cephalopoda, Ommastrephidae). In: Voss, N.A., et al. (eds.) Systematics and Biogeography of Cephalopods. Smithson. Contr. Zool. 586:405-423.

    Title Illustrations
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    Scientific Name Illex oxygonius
    Location Off Key West, Florida, western North Atlantic at 2413'N, 8158'W
    Reference Roper, C.F.E., C.C. Lu, and K. Mangold. 1969. A New Species of Illex from the Western Atlantic and Distributional Aspects of Other Illex Species (Cephalopoda: Oegopsida). Proceedings of the Biological Society of Washington, 82:295-322.
    Creator J. Schroeder
    Sex Male
    View Dorsal, ventral
    Size 207 mm ML
    Type Holotype
    Copyright ©
    About This Page


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


    Smithsonian Institution, Washington, D. C., USA


    University of Hawaii, Honolulu, HI, USA

    Page: Tree of Life Illex oxygonius Roper, Lu & Mangold 1969. Authored by Michael Vecchione, Clyde F. E. Roper, 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.

    Citing this page:

    Vecchione, Michael, Clyde F. E. Roper, and Richard E. Young. 2011. Illex oxygonius Roper, Lu & Mangold 1969. Version 13 January 2011 (under construction). http://tolweb.org/Illex_oxygonius/77446/2011.01.13 in The Tree of Life Web Project, http://tolweb.org/

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