Grimpoteuthis tuftsi Voss & Pearcy, 1990

Introduction

G. tuftsi is known only from the type description which is based on seven specimens captured in bottom trawls during a study of the fauna of the continental slope and the Tufts and Cascadia Abyssal Plains in the Northeastern Pacific. The largest individual has a total length of 475 mm.

Characteristics

1. Web
   1. Web formula variable, generally ABCDE.
   2. Web nodule at midpoint of each arm, ventral side.
   3. Web nodule near but not at end of web.
   4. On dorsal arm margin web extends nearly to arm tip.
   

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   Figure. Oral view of arms, web and suckers of G. tuftsi. Drawing from Voss and Pearcy (1990).

2. Suckers and cirri
   1. Arms I each with 63-75 suckers.
   2. Maximum sucker diameter 2.5 - 5.3% of ML.
   3. Suckers united by thin transparent web or membrane along oral surface of arms.
   

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   Figure. Lateral view of suckers and cirri of G. tuftsi, male, 93 mm ML. Note weak membrane between suckers. Drawing from Voss and Pearcy (1990).

   4. First 6-7 suckers small, then gradually increase to maximum diameter at about level of nodule.
   

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   Figure. Oral view of left arm I of G. tuftsi, male, 93 mm ML. Drawing from Voss and Pearcy (1990).

   5. Sexual dimorphism absent.
   6. First cirri between suckers 5-7.
   7. Cirri long, maximum length 1.5-3.5 x largest sucker diameter.
   8. Cirri extend to arm tip.
   

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   Figure. Right arm I of G. tuftsi enlarged from oral view of arms above. Drawing from Voss and Pearcy (1990).

3. Shell
   1. U- or rounded V-shaped with a hint of central bend in saddle (i.e., weak W-shaped).
   2. Somewhat constricted at posterior end.
   3. Wings taper to thin, flat, straplike, truncated tips.
   

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   Figure. Dorsal (left) and ventral (right) views of shell of G. tuftsi, male, 72 mm ML. Drawing from Voss and Pearcy (1990).

Comments

The above description is taken from Voss and Pearcy (1990). More details of the description of G. tuftsi can be found here.

G. tuftsi can be separated from all other members of the genus by the transverse groove in the outer surface of the shell saddle. This groove gives the shell a weak W-shape which is somewhat similar to but not as strong as in species of Luteuthis. Among other Pacific species, G. tuftsi differs from:

• G. abyssicola by features of the shell (presence of shoulder blades, transverse groove and non-expanded wings).
• G. bathynectes in having a transverse groove on the external surface of the shell saddle, no sexual dimorphism in sucker shape, more elongate gills, longer cirri, presence of enlarged suckers near web nodules and presence of a radula (Voss and Pearcy, 1990).
• G. hippocrepium in having a transverse groove on the external surface of the shell saddle and shell shoulder blades.
• G. innominata in having a transverse groove on the external surface of the shell saddle and no median ridge, more suckers (63-75 vs 50-60), longer cirri (1.5-3.5x vs 1x), and, possibly, a shorter gill (half-orange vs semi-sepioid vs).
• G. meangensis in having a transverse groove on the external surface of the shell saddle.
• G. pacifica in having more suckers (63-75 vs 52).

Nomenclature

O'Shea (1999) suggested that G. tuftsi might be a Luteuthis; however Collins (2003) after examining the holotype of G. tuftsi, concluded that this species should remain in Grimpoteuthis.

Distribution

L. tuftsi is known only from the Tufts Abyssal Plain off Oregon, USA. Type locality: 45°05.2'N, 134°43.4'W, 3900 m.

References

Collins, M. A. 2003. The genus Grimpoteuthis (Octopoda: Grimpoteuthidae) in the North-east Atlantic, with descriptions of three new species. Zool. Journ. Linnean Soc., 139: 93-127.

O'Shea, Steve. 1999. The Marine Fauna of New Zealand: Octopoda (Mollusca: Cephalopoda). NIWA Biodiversity Memoir 112: 280pp.

Voss, G. L. and W. G. Pearcy. 1990. Deep-water octopods (Mollusca: Cephalopoda) of the Northeastern Pacific. Proc. Calif. Acad. Sci. 47: 47-94.