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Pyroteuthis Hoyle, 1904

Richard E. Young and Katharina M. Mangold (1922-2003)
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Pyroteuthis contains three species.
taxon links [up-->]Pyroteuthis addolux [up-->]Pyroteuthis serrata [up-->]Pyroteuthis margaritifera [down<--]Pyroteuthidae Interpreting the tree
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Containing group: Pyroteuthidae

Introduction

Members of Pyroteuthis are similar in appearance to those of Pterygioteuthis except that they are larger as adults and tend to have broader heads.

Brief diagnosis:

A pyroteuthid ...

Characteristics

  1. Arms
    1. Arm hooks in two series.
    2. More than 13 hooks/arm.
    3. Arms IV with >16 hooks.
    4. Right arm IV hectocotylized; toothed plate absent.
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      Figure. Side view of a lateral arm of P. addolux. Photograph by R. Young.

  2. Tentacles
    1. Tentacular club with one series of hooks and three series of suckers on manus.
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      Figure. Oral (top), oral (middle) (preserved) and side (bottom) (live) views of a P. addolux club showing the presence of a single series of hooks in the proximal portion of the club.

  3. Photophores
    1. Eyeball without a lidded photophore.
    2. Six or seven separate photophores in tentacular stalk.
    3. Three anterior abdominal and small branchial photophores.

  4. Oviducts.
    1. Both present; right may be reduced.

Comments

The major differences between the species lie in:

  1. the arrangement of tentacular photophores.
  2. the form of the hectocotylus.
  3. the shape of the hooks on the hectocotylus.

Discussion of Phylogenetic Relationships

P. addolux is more similar to P. serrata than to P. margaritifera in the arrangement of tentacular photophores and in the structure of the hectocotylus (Riddell, 1985).

Behavior

The quick, brilliant bioluminescent flashes observed in Pterygioteuthis spp. have not been seen in Pyroteuthis spp. This is not surprising since comparable photophores in Pyroteuthis are either absent (lidded ocular photophore) or less specialized (branchial photophores). However, we have seen P. addolux produce a peculiar, long-duration flash where all tentacular photophores, among others, glow for up to 4 or 5 seconds. We call this the Y-pattern display since the photophores are aligned in a pattern of this shape. All of the photophores involved have not been clearly identified but include four tentacular photophores and some ocular and visceral organs. To produce the Y-pattern, the tentacles are held straight and rigid at angles of approximately 45° to the body axis. This behavior is illicited when the squid is distrubed without direct physical contact. When physical contact is involved (i.e., squid touched or grabbed), the same photophores seem to be involved but the tentacles undulate instead of being held rigid.

Pyroteuthis addolux has been shown in the laboratory to counterilluminate (i.e., use bioluminescence to match the dim downwelling light and thereby eliminate the squid's silhouette) (Young and Roper, 1977). The photophores involved were, apparently, the ocular and anal organs.

Distribution

Species of Pyroteuthis are found throughout most of the tropical and temperate regions of the world's oceans but they are apparently absent from the Tropical Eastern Pacific (Nesis, 1982).

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This map shows the general localities (white circles) where Pyroteuthis has been captured. Areas where pyroteuthids, other than members of this genus, have been captured are represented by yellow crosses. (Records are listed here).

References

Nesis, K. N. 1982/87. Abridged key to the cephalopod mollusks of the world's ocean. 385+ii pp. Light and Food Industry Publishing House, Moscow. (In Russian.). Translated into English by B. S. Levitov, ed. by L. A. Burgess (1987), Cephalopods of the world. T. F. H. Publications, Neptune City, NJ, 351pp.

Riddell, D. J. 1985. Enoploteuthidae of the New Zealand Region. Fisheries Research Bulletin. New Zealand Ministry of Agriculture and Fisheries, No.27: 1-52.

Young, R. E. and C. F. E. Roper (1977). Intensity regulation of bioluminescence during countershading in living midwater animals. Fish. Bull., U.S., 75: 239-252.

Title Illustrations
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Scientific Name Pyroteuthis addolux
Location Hawaiian waters
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © 1996
About This Page


University of Hawaii, Honolulu, HI, USA

Katharina M. Mangold (1922-2003)
Laboratoire Arago, Banyuls-Sur-Mer, France

Page: Tree of Life Pyroteuthis Hoyle, 1904. Authored by Richard E. Young and Katharina M. Mangold (1922-2003). 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:

Young, Richard E. and Katharina M. Mangold (1922-2003). 2009. Pyroteuthis Hoyle, 1904. Version 29 December 2009 (under construction). http://tolweb.org/Pyroteuthis/19748/2009.12.29 in The Tree of Life Web Project, http://tolweb.org/

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