Note

Walvisteuthis rancureli: Description of the Holotype

Richard E. Young, Michael Vecchione, Kotaro Tsuchiya, and K.S.R. Bolstad
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Click on an image to view larger version & data in a new window
  

Figure. Illustrations of the holotype of Walvisteuthis rancureli. Left - Dorsal view. Right - Ventral view. Photographs by R. Young.


Introduction

Okutani described Onykia rancureli primarily from four squid taken from the stomach of a lancet fish (Alepisaurus ferox) caught in the tropical Indian Ocean. He examined additional material from over the South Pacific as well and considered it the same species as the type series. He also considered that specimens described as Onykia sp. Rancurel (1970) from fish stomachs belonged to this species. The species described by Okutani was so different from other species of Onykia that the minor differences seen among the specimens he examined, presumably, were considered unimportant. The following description is mostly taken from the original but clarifications based on the examination of the holotype are included.

Description

  1. Arms
    1. Arms with broad dorsal protective membranes and long trabeculae (see arrows).
    2. Ventral protective membranes and trabeculae short.
    3. Suckers lack distal fleshy swelling.
    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. Dorsal view of mid-region of arms II and III of W. rancureli, holotype. The shape of the horny rings of the suckers was completely destroyed apparently by the stomach acid of the predator. White arrows point to trabeculae of the protective membrane. Photograph by R. Young.

  2. Tentacle
    1. Stalk with a aboral carina.
    2. Carpal locking apparatus with 9 suckers.
    3. Club with two series of hooks: 25 hooks on the left club and 24 on the right. The apparent single series in the drawing to the left is an artifact of the poor condition of the club.
    4. Largest hooks in ventral series on club are numbers 4 and 5 from the proximal end.
    5. The terminal pad has seven to nine small suckers.
    6. A few marginal suckers are present proximally on the club on either side.
    7. 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 views of tentacular club of W. rancureli. Top - Drawing from Okutani, 1981. Bottom - Photograph by R. Young of the holotype.Very little remains of the shape or precise size of the hooks due, apparently to the stomach acid of the predator.

  3. Head
    1. In the type series, the number of occipital folds is unclear but at least two are present on the holotype.
    2. Beaks
      1. Upper beak with an acute jaw angle; hood "moderately" apart from the crest; rostrum gently curves.
      2. Lower beak with "moderately" distinct wing fold hides obtuse jaw angle; hood short and close to crest; crest narrow; lateral wall ridge extends halfway between crest and inner posterior corner.
      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 views of beaks of W. rancureli. Drawings from Okutani, 1981.

    3. Radula
      1. Lateral tooth 2 is smaller than the rhachidian or lateral tooth 1. The unusual radula (see below) was not available for us to check.
      2. 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. Radula of W. rancureli. Drawing modified from Okutani, 1981.

  4. Funnel
    1. Funnel groove without typical V-shape. Presumably this is an artifact resulting from the squid's residence in the stomach of its predator.
    2. 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 head and funnel of W. rancureli, holotype. Photograph by R. Young.

  5. Gladius
    1. Minute, cap-like rostrum.
    2. Widest point two thirds GL from anterior end.
    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 view of the posterior end of the gladius of W. rancureli. Drawing from Okutani, 1981.

  6. Measurements

  7. Holotype Paratype Paratype
    Sex F F F
    ML, mm 68 43.5 57.6
    MW, % ML 42.5 48.5 41.7
    Head W, % ML 36.8 40.0 35.6
    Fin L, % ML 47.1 38.4 46.9
    Fin W, % ML 105.3 97.5 100.2
    Arm I, % ML 72.4 52.9 67.7
    Arm II, % ML 86.5 69.0 78.8
    Arm III, % ML 90.0 69.9 81.6
    Arm IV, % ML 82.2 - 77.4
    Club L, % ML 42.6 39.5 42.2

Comments

The lateral tooth 2 on the radula is the smallest tooth in Okutani's material but ranks second in size in Rancurel's 1970 description of W. rancureli (his Onykia sp.) from the South Pacific. The radula illustrated by Rancurel is very similar to that of W. youngorum from Hawaiian waters.

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. Radula of W. rancureli. Drawing from Rancurel, 1970.

Okutani (1981) states that the holotype is a female. We were unable to identify nidamental glands or a penis.

Distribution

The type locality is a fish captured at 07°51'S, 88°02.5'E in the tropical central Indian Ocean. Other squid in the type series came from fish captured at 09°15'S, 83°45'E, 09°21'S, 81°42'E, 11°16.2'S, 109°29.5'E in the tropical central and eastern Indian Ocean.

References

Okutani, T. 1981. Two new species of the squid genus Onykia from the tropical Indian Ocean (Cephalopoda, Onychoteuthidae). Bull. Nat. Sci. Mus., Tokyo, Ser. A. 7: 155-163.

Rancurel, P. 1970. Les contenus stomacaux d'Alepisaurus ferox dans le Sud-ouest Pacifique (cephalopodes). Cah. O.R.S.T.O.M., ser. Oceanogr., 8: 3-87.

About This Page


University of Hawaii, Honolulu, HI, USA


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


Tokyo University of Fisheries, Tokyo, Japan


EOS Research Institute, Auckland University of Technology, New Zealand

Correspondence regarding this page should be directed to K.S.R. Bolstad at

Page: Tree of Life Walvisteuthis rancureli: Description of the Holotype Authored by Richard E. Young, Michael Vecchione, Kotaro Tsuchiya, and K.S.R. Bolstad. 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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