Gonatus oregonensis Jefferts 1985

Introduction

Gonatus oregonensis is known only from young squid of 46 mm ML or less and has only been reported from the general region of the type locality. 

Diagnosis

A Gonatus with ...

• more than 4 sucker series throughout club dactylus.
  

Characteristics

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Figure. Ventral view of Gonatus oregonensis, holotype, 39 mm ML. Photograph by R. Young.

1. Arms
   1. Arm lengths 59-63% of the ML at 46 mm ML.
      
   2. Number of suckers in proximal half of each arm IV at 46 mm ML = 47.
      

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      Figure. Oral view of arm III and arm III sucker of G. oregonensis, 46 mm ML. Drawings from Jefferts (1985).
      

2. Tentacles
   1. Tentacular club 21-30% of ML.
   2. Club dactylus with 7-8 irregular series at proximal end, decreasing to 5 or 6 series at the end of the dactylus.
   3. Club ventral-marginal zone with 4-5 series of suckers in central region; medial suckers ca. one-half diameter of suckers of marginal series (holotype).
   4. Club dorsal-marginal zone with 3-4 irregular series dorsal to large central hook (holotype).
   5. Club medial zone with large central hook; medium (ca. half size of central hook) distal hook and proximal series with usually 4 small hooks followed proximally by usually 2 suckers (46 mm ML).
   6. Total number of suckers (excluding terminal pad and medial zone) on tentacular club: 295-370.
   7. Median region of tentacular stalk between marginal series with ca. 70 scattered suckers (46 mm ML); in 24 mm ML squid stalk suckers in 6, somewhat irregular, alternating rows.
   

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   Figure. Oral views of the tentacle and some club suckers of G. oregonensis, 46 mm ML. Top  - Tentacle and dactylus sucker. Middle - Tentacular club (enlargement from above drawing). Bottom -  Proximal hooks and suckers of the medial zone of the tentacular club (enlargement from above drawing). Drawings from Jefferts (1985).

   

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   Figure. Oral view of the tentacle of G. oregonensis, holotype, preserved. Photograph by R. Young.

3. Photophores absent

Comments

The above description, except for photographs and characters annotated with "holotype", is taken from Jefferts (1985). More details of the description can be found here.

Jefferts finds G. oregonensis similar to G. californiensis but differing in fin size, number of club suckers and distribution of suckers on the dactylus.

We have compared the holotype side by side with two specimens of G. californiensis of about the same size as the holotype.  The two species are very similar but the differences noted by Jefferts seem to hold true. We have also noted that the arm hooks of G. oregonensis are distinctly larger than those of the G. californiensis examined. However, until larger specimens are found and intraspecific variation is better understood, the validity of this species must retain an element of doubt.

Life History

1. Arm hooks develop at 24-30 mm ML.
2. Central and distal club hooks develop at 24-30 mm ML.
3. Proximal club hooks develop at 35-39 mm ML; sucker nearest the central hook is the first of proximal series to become a hook.

Distribution

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Figure. Distribution of G. oregonensis. Dark pink area indicates known range. Chart modified from Okutani, et al. (1988). 

References

Jefferts, K. 1985. Gonatus ursabrunae and Gonatus oregonensis, Two New Species of Squids from the Northeastern Pacific Ocean (Cephalopoda: Oegopsida: Gonatidae). Veliger, 28(2):159-174.

Okutani, T., T. Kubodera and K. Jefferts. 1983. Diversity, distribution and ecology of gonatid squids in the subarctic Pacific: A review. Bull. Ocean Res. Inst., Univ. Tokyo, No. 26 (1):150-192.