Gonatus
Tsunemi Kubodera, F. G. Hochberg, Richard E. Young, and Michael VecchioneThis tree diagram shows the relationships between several groups of organisms.
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close boxIntroduction
Gonatus, the most speciose genus in the family, has its highest diversity in the high North Pacific. These squids reach a maximum length of 39 cm ML.
Diagnosis
A gonatid ...
- with one or more hooks in median line on tentacular club.
Characteristics
- Arms
- Hooks in two medial series on arms I-III.
- Tentacles
- Tentacles present in subadults.
- Tentacular club with one or more hooks in median line; one greatly enlarged.
- Proximal locking-apparatus of club with suckers and knobs medial to 4-6 large ridges and grooves, and usually several smaller ones.
- Head
- Radula with 5 teeth in transverse row.
- Mantle
- Mantle tissue muscular or flabby depending on species.
- Fins
- Fins sagittate, drawn out posteriorly into a short tail.
- Photophores
- Ocular photophores present only in G. pyros.
Comments
Many of the species characteristics are found on the tentacles. The tentacles are complex and for descriptive purposes the club and stalk are divided into various zones, regions and series as follows:
Figure. Oral view of the club and distal stalk of G. californiensis showing the terminology (much of it color coded) used in describing the tentacle. Drawing modified from Young (1972).
The following table compares some characteristics of subadult species of Gonatus. The most useful character states are indicated in bold-red. The table doesn't separate all species.
Species / Character | Habitat | Ocular light organs | Proximal club hooks | Distal club hook | Medial suckers of tentacular stalk | Suckers on club | Club suckers of dorsal- and ventral marginal zones merge proximally. | Arm II< III length | Club length |
G. antarcticus | Antarctic waters | No | Yes | Yes | 120-140 | 250-315 | No | 40-50% ML | 16-17% ML |
G. berryi | North Pacific | No | Yes | Yes | 0-2 | 159-181 | No | 60-70% GL | 30-37% GL |
G. californiensis | North Pacific | No | Yes | Yes | 40-80 | 215-270 | No | 46-53% GL | 17-24% GL |
G. fabricii | North Atlantic | No | Yes | Yes | 38-109 | 155-229 | No | 53-59% GL | 12-20% GL |
G. madokai | North Pacific | No | Yes | Yes | Many | ? | Yes | 90% ML | 20% ML |
G. middendorffi | North Pacific | No | No | Yes | Few | ? | No | 50% ML | 10% ML |
G. onyx | North Pacific | No | No | No | 0-27 | 160-200 | No | 48-54% GL | 20-25% GL |
G. oregonensis | North Pacific | No | Yes | Yes | 70 | 295-370 | No | 59-63% ML | 21-30% ML |
G. pyros | North Pacific | Yes | Yes | Yes | 50-125 | 151-184 | No | 60-70% GL | 20-25% GL |
G. steenstrupi | North Atlantic | No | Yes | Yes | 75-165 | 190-225 | No | 50-70% GL | 20-36% GL |
G. ursabrunae* | North Pacific | No | ? | ? | ? | ? | ? | 42-56% ML | 13-25% ML |
*Known only from juveniles but with distinctive relative sucker sizes on arms and club dactylus.
Behavior
The tip of the tail (see arrow below) in Gonatus spp. is loosely attached to the mantle. The photograph below shows the fins apparently separating from the mantle tip. Although not visible in the photograph, transparent integument does extend between the tip of the mantle and the fins. The tip of the fins can also curve ventrally beneath the mantle tip. Presumably this unusual flexibility of the tip of the fins enables an enhanced role for the fins in maneuvering.Life History
Brooding of egg masses in G. onyx (Seibel et al., 2000) [suspected in G. fabricii (Bjorke et al., 1997)] occurs in deep water. Such brooding behavior, rare in oceanic squids, may prove to be characteristic of all members of the genus and perhaps the entire family. The long brooding period demanded by cold temperatures in deep water and its resulting slow population turnover rate, presumably is offset, in evolutionary time, by low egg mortality in the vast, dark, lowly populated bathypelagic environment (see Seibel, et al., 2000). For more information on brooding behavior, go to the G. onyx page.
References
Nesis, K. N. (1982). Abridged dey 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.
Okutani, T. and M. R. Clarke (1992). Family Gonatidae Hoyle, 1886. P. 139-156. In: Sweeney, M. J., C. F. E. Roper, K. M. Mangold, M. R. Clarke and S. V. Boletzky (eds.). "Larval" and juvenile cephalopods: a manual for their identification. Smiths. Contr. Zool., No. 513.
Seibel, B. A., F. G. Hochberg, and D. B. Carlini. 2000. Life history of Gonatus onyx (Cephalopoda: Teuthoidea): deep-sea spawning and post-spawning egg care. Marine Biology 137 (3): 519-526.
Seibel, B. A., B. H. Robison and S. H. D. Haddock. 2005. Post-spawning egg care by a squid. Nature 438: 929.
About This Page
National Science Museum, Tokyo, Japan
F. G. Hochberg
Santa Barbara Museum of Natural History, Santa Barbara, California, USA
Richard E. Young
University of Hawaii, Honolulu, HI, USA
National Museum of Natural History, Washington, D. C. , USA
Page copyright © 2012 , F. G. Hochberg, Richard E. Young, and
Page: Tree of Life Gonatus Authored by . Tsunemi Kubodera, F. G. Hochberg, Richard E. Young, and Michael Vecchione. 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.
- Content changed 10 November 2012
Citing this page:
Kubodera, Tsunemi, F. G. Hochberg, Richard E. Young, and Michael Vecchione. 2012. Gonatus http://tolweb.org/Gonatus/19767/2012.11.10 in The Tree of Life Web Project, http://tolweb.org/
. Version 10 November 2012 (under construction).