Under Construction

Cycloteuthis Joubin, 1919

Cycloteuthis sirventi Joubin, 1919

Richard E. Young
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
Cycloteuthis contains one recognized species.
Containing group: Cycloteuthidae

Introduction

Cycloteuthis sirventi is easily distinguished from species of Discoteuthis by the general shape which includes a tail. Maximum known size is 480 mm ML (Clarke, 1986). This is probably the most common member of the family but, nevertheless, little is known of its biology.

Brief diagnosis:

A cycloteuthid ...

Characteristics

  1. Arms
    1. Large suckers from arm III with ca. 20 low, truncate teeth (larger distally) around entire margin.
      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
      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 view of inner ring of large arm suckers of C. serventi. Left to right - Suckers from arms I - IV respectively. Drawing from Young and Roper (1969).

  2. Tentacles
    1. Suckers nearly equal in size across manus of club.
    2. Suckers from club manus with ca. 20 teeth, pointed distally and truncated proximally.
      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
      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. Left - Oral view of tentacular club of C. serventi, 42 mm ML.  Drawing from Young and Roper (1969).

      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 suckers of C. sirventi. Left - Manus sucker with outer ring intact. Middle - Manus sucker showing inner ring only. Right - Dactylus sucker showing inner ring only.Drawings from Young and Roper (1969).

  3. Head
    1. Beaks: Descriptions can be found here: Lower beak; upper beak.

  4. Mantle
    1. Tail present.

  5. Fins
    1. Fins large, oval, length about 80% of ML in subadults.

  6. Photophores
    1. Large photophore on ink sac.
    2. Irregular series of small photophores apparently at edge of iris; large photophore on ventral surface of eyeball.
      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 the visceral nucleus of C. serventi. Drawing from Young and Roper (1969).

  7. Gladius
    1. Gladius with a secondary conus.
      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

      Ventral view of the gladius of C. sirventi. Drawing from Young and Roper (1969).

Nomenclature

A second species, Cycloteuthis akimushkini Filippova, 1968, has been described. This description was based on a very large specimen and apparent differences between this species and C. sirventi may be due to size effects alone. This species is considered to be a synonym of C. sirventi at present.

Life History

C. serventyi has a very distinctive paralarva. The second arms are very long and a thick, transparent dermal layer is present in the integument. Each eye is on a stalk but, unlike many cranchiids, the optic lobe is attached to the central brain and long retinal nerves connect it to the eye.

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 and dorsal views of a paralarva of C. serventyi, 8.1 mm ML, Hawaiian waters. The scale bar is 1 mm. Drawings by R. Young.

Other Names for Cycloteuthis sirventi Joubin, 1919

References

Clarke, M. R. 1986. A Handbook for the Identification of Cephalopod Beaks. Clarendon Press, Oxford. 273 pp.

Filippova, J. A. 1968. A new species of the genus Cycloteuthis. Malacol. Rev., 1: 119-124.

Nesis, K. N. 1982. 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.

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
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
Scientific Name Cycloteuthis sirventyi
Location off Florida
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.
Size 42 mm ML
About This Page


University of Hawaii, Honolulu, HI, USA

Page: Tree of Life Cycloteuthis Joubin, 1919. Cycloteuthis sirventi Joubin, 1919. Authored by 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:

Young, Richard E. 2016. Cycloteuthis Joubin, 1919. Cycloteuthis sirventi Joubin, 1919. Version 29 August 2016 (under construction). http://tolweb.org/Cycloteuthis_sirventi/19620/2016.08.29 in The Tree of Life Web Project, http://tolweb.org/

edit this page
close box

This page is a Tree of Life Leaf Page.

Each ToL leaf page provides a synopsis of the characteristics of a group of organisms representing a leaf at the tip of the Tree of Life. The major distinction between a leaf and a branch of the Tree of Life is that a leaf cannot generally be further subdivided into subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

close box

Cycloteuthis sirventi

Page Content

articles & notes

collections

people

Explore Other Groups

random page

  go to the Tree of Life home page
top