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Discoteuthis discus Young and Roper 1969

Richard E. Young
Containing group: Discoteuthis

Introduction

Discoteuthis discus is most easily separated from its congeners by the arrangement of photophores and the structure of the funnel locking-apparatus.

Diagnosis 

A Discoteuthis ... 

Characteristics


  1. Arms
    1. Arms weak, approximately subequal and 60-85% of ML.
    2. Large arm suckers with few low, broad, rounded teeth mostly on distal margin.
    3.  image info

      Figure. Oral views of large arms suckers of D. discus, 45 mm ML. Left to right - Sucker of arms I-IV respectively. Drawing from Young and Roper (1969).

  2. Tentacles
    1. Dactylus with suckers in four series throughout.
    2. Medial suckers on manus of club globular relative to D. laciniosa (inner ring height ca 60% of diameter compared to 35% of diameter).
       image info  image info

      Figure. Left - Side views of large manus suckers from D. discus (45 mm ML) and D. laciniosa (56 mm ML, paratype). Right - Oral views of a large sucker from manus and a much smaller sucker from the dactylus of D. discus, 45 mm ML, showing dentition. Drawings from Young and Roper (1969).

    3. Largest club suckers with numerous low, flattened or rounded teeth around entire inner ring.
       image info

      Figure. Oral view of the tentacular club of D. discus, 53 mm ML, holotype. Drawing from Young and Roper (1969).

  3. Funnel
    1. Locking-apparatus with diagonally positioned groove.
       image info

      Figure. Frontal view of the funnel locking-apparatus of D. discus, 45 mm ML. Drawing from Young and Roper (1969).

  4. Mantle
    1. Free anterior margin of mantle smooth (i.e., flaps lacking).
  5. Photophores
    1. At least 4 organs on margin of eyelid.
    2. One dark, round organ on ventral surface near posterior tip of mantle.
    3.  image info

      Figure. Ventral view of posterior tip of mantle and fins of D. discus, 53 mm ML, holotype. Drawing modified from Young and Roper (1969).

  6. Gladius
    1. Conus absent.
    2.  image info

      Figure - Ventral view of the gladius of D. discus, 53 mML, holotype, with cross-sections shown above. Drawing from Young and Roper (1969).

Life History

The smallest known D. discus is 16 mm ML (Young and Roper, 1969). At this size, the fins are about 60% of the ML and reach 98% of the ML in squid of 45 mm ML. Mature individuals are not known.

Distribution

The type locality is off Ghana, West Africa (03 deg 50'M. 02 deg 37'W) in the tropical East Atlantic. This species is known from the tropical and subtropical Atlantic and the central North Pacific (M. Seki, pers. comm.).

References

Young, R. E. and C. F. E. Roper. 1969. A monograph of the Cephalopoda of the North Atlantic: The family Cycloteuthidae. Smithsonian Contributions to Zoology No. 5:1-24.

Title Illustrations
Scientific Name Discoteuthis discus
Location Off West Africa, 4?N, 3?W
Reference from Young, R. E. and C. F. E. Roper. 1969. A monograph of the Cephalopoda of the North Atlantic: The family Cycloteuthidae. Smithsonian Contributions to Zoology No. 5:1-24.
View Ventral
Size 53 mm ML
Type holotype
Copyright © Richard E. Young
About This Page

Richard E. Young

Dept of Oceanography
University of Hawaii
Honolulu, Hawaii 96822
USA

Citing this page:

Young, Richard E. 1999. Discoteuthis discus Young and Roper 1969. Version 01 January 1999 (under construction). http://tolweb.org/Discoteuthis_discus/19625/1999.01.01 in The Tree of Life Web Project, http://tolweb.org/

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Discoteuthis discus

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