- Hooks in two medial series on arms I-III.
- 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.
Figure. Oral view of tentacular club of G. californiensis, 315 mm GL, immature female, preserved. Photograph of preserved club by R. Young.
- Radula with 5 teeth in transverse row.
- Mantle tissue muscular or flabby depending on species.
- Fins sagittate, drawn out posteriorly into a short tail.
- Ocular photophores present only in G. pyros.
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.
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