Overview

Brief Summary

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 ...

  • with one series of hooks on club manus.
  • with more than 13 hooks on each arm.

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Comprehensive Description

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.

      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.



      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.

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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).

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).

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Ecology

Habitat

Depth range based on 29 specimens in 1 taxon.
Water temperature and chemistry ranges based on 16 samples.

Environmental ranges
  Depth range (m): 31 - 2075
  Temperature range (°C): 2.243 - 25.407
  Nitrate (umol/L): 0.011 - 38.940
  Salinity (PPS): 34.050 - 35.045
  Oxygen (ml/l): 2.397 - 5.686
  Phosphate (umol/l): 0.154 - 2.810
  Silicate (umol/l): 1.411 - 133.928

Graphical representation

Depth range (m): 31 - 2075

Temperature range (°C): 2.243 - 25.407

Nitrate (umol/L): 0.011 - 38.940

Salinity (PPS): 34.050 - 35.045

Oxygen (ml/l): 2.397 - 5.686

Phosphate (umol/l): 0.154 - 2.810

Silicate (umol/l): 1.411 - 133.928
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Life History and Behavior

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.

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Evolution and Systematics

Evolution

Discussion of Phylogenetic Relationships

View Pyroteuthis Tree

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).

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
Specimen Records: 11
Specimens with Sequences: 10
Specimens with Barcodes: 10
Species: 3
Species With Barcodes: 3
Public Records: 1
Public Species: 1
Public BINs: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Barcode data

Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

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Wikipedia

Pyroteuthis

Pyroteuthis is a genus of squid in the family Pyroteuthidae. It is differentiated from the genus Pterygioteuthis by size, head shape and behaviour. Species within the genus are separated by the arrangement of tentacular photophores; the shape of the hectocotylus, and the shape of the hectocotylus hooks. With the exception of the Tropical Eastern Pacific, the genus is circumpolar in tropical and temperate oceans. The species P. addolux is the only member to occur in the North Pacific.

Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

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