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Planctoteuthis oligobessa Young 1972

Richard E. Young and Clyde F. E. Roper
The holotype is deposited in the Santa Barbara Museum of Natural History, Santa Barbara, California.
Containing group: Planctoteuthis


Planctoteuthis oligobessa is a small species (maximum size = 76 mm ML). It can be separated from subadults of other members of the genus by the small fins and few suckers on arms IV. Little is known of its biology.


A Planctoteuthis with ...


  1. Arms
    1. 2-4 suckers on each arm IV.
    2. Arm lengths: Arms I: 32-39% of ML (subadults); arms I: 24-25% of ML (adults); arms III: 47-61% of ML (subadults). arms IV: 121-135% of ML (subadults); arms II-IV 29-39% of ML (adults).
    3. Large arm suckers with 25-35 small, narrow, blunt teeth on distal 3/4 of ring.

      Figure. Oral view of large arm suckers of P. oligobessa, 27 mm ML. A-D - Suckers from arm I-IV respectively.

  2. Tentacles
    1. Clubs bilaterally symmetrical in shape.
    2. Club length 12-18% of ML.
    3. Suckers without teeth on inner ring.
    4. Clubs without keels.

      Figure. Oral views of club sucker and club, 27 mm ML. Drawings from Young (1972).

  3. Funnel
    1. Locking apparatus with slender antitragus consisting of a single lobe.

      Figure. Funnel locking apparatuses of P. oligobessa. Left - 27 mm ML. Drawing from Young (1972). Right - Subadult, off Southern California.

  4. Fins
    1. Length 23-33% of ML.
  5. Measurements
      Paratype Paratype Holotype
    Sex -- -- Female
    Mantle length 34 34 76
    Mantle width 11 11 28
    Fin length 7 8 14
    Fin width 12 -- --
    Length, arm I 12 11 19
    Length, arm II 15 15 27
    Length, arm III 18 16 29
    Length, arm IV 46 41 30
    Club length* 6 4 --
    Arm IV sucker count (left / right) 3 / -- 3 / 2 2 / 3
    *Without carpus


Individuals taken in trawls invariably show a broken gladius at the posterior end of the fin. The existence of a long and decorative tail was not known until this ROV photograph taken by the Monterey Bay Aquarium Research Institute was obtained at 32° 52.29 N, 131° 17.49 W. The ventrally bulging eyes identify it as Planctoteuthis and the locality strongly suggests that it is P. oligobessa. The function of the tail is unknown although Vecchione et al. (1992) noted that the tail of Chiroteuthis (see Chiroteuthidae page) causes the young squid to resemble certain siphonophores suggesting protective mimicry.

Figure. Lateral view, insitu, apparently of P. oligobessa, taken by a remotely operated vehicle (ROV) off California, © MBARI 2001 http://www.mbari.org/rd/midwater


This species was originally described as Valbyteuthis oligobessa. ValbyteuthisPlanctoteuthis (Young, 1991).

is now placed in the synonomy of

Life history

Paralarval stages are unknown.

The holotype is a gravid, mated female with mature ovarian eggs of 1.5 mm in diameter. Spermatangia were found within the ovary. Fertilization, apparently, is internal.


Vertical distribution

The vertical distribution of P. oligobessa off southern California extends from 700 - 1200m (the maximum depth of the trawling program). The highest capture rate occurred in the 1100-1200 m zone and this species was one of the deepest living cephalopods taken in this program (Roper and Young, 1975). There is no difference between daytime and nighttime distributions.

Geographical distribution

P. oligobessa has been described only from the waters off southern California and northern Baja California; Nesis (1982/87) indicates that the distribution extends to Indonesian waters.


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.

Roper, C. F. E. and R. E. Young. 1975. Vertical distribution of pelagic cephalopods. Smithsonian Contributions to Zoology, 209: 1-51.

Vecchione, M., B. H. Robison, and C. F.E. Roper. 1992. A tale of two species: tail morphology in paralarval Chiroteuthis (Cephalopoda: Chiroteuthidae). Proceeding of the Biological Society of Washington 105(4): 683-692.

Young, R. E. 1972. The systematics and areal distribution of pelagic cephalopods from the seas off southern California. Smithson. Contr. Zool., No. 97: 159pp.

Young, R. E. (1991). Chiroteuthid and related paralarvae from Hawaiian waters. Bull. Mar. Sci., 49: 162-185.

Title Illustrations
Scientific Name Planctoteuthis oligobessa, Planctoteuthis oligobessa (2)
Location Pacific Ocean off California
Comments note the long arms IV and the strong ventral protrusion of the eyes from the head (1)
Reference Young, R. E. 1972. The systematics and areal distribution of pelagic cephalopods from the seas off southern California. Smithson. Contr. Zool., No. 97: 159pp
Creator C. McSweeny
Specimen Condition Dead Specimen
Sex f (2)
Life Cycle Stage subadult, mature (2)
View Ventral
Size 23 mm ML, 76 mm ML (2)
Type holotype (2)
Copyright © Richard E. Young
About This Page

Richard E. Young

Dept of Oceanography
University of Hawaii
Honolulu, Hawaii 96822

Citing this page:

Young, Richard E. and Roper, Clyde F. E. 1999. Planctoteuthis oligobessa Young 1972. Version 01 January 1999 (under construction). http://tolweb.org/Planctoteuthis_oligobessa/19496/1999.01.01 in The Tree of Life Web Project, http://tolweb.org/

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