Grimpoteuthis challengeri Collins 2003

Introduction

Grimpoteuthis challengeri is a large abyssal species recently described from the Porcupine Abyssal Plain in the N. E. Atlantic with one record from the N. W. Atlantic (Collins, 2003).

Characteristics

1. Arms and web
   

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   Figure. Oral view of arms and web of C. challengeri, male, 58 mm ML, holotype. Drawings from Collins (2003).

   1. Arms long, subequal in length.
   2. Web extends 2/3 of arm length; extends farther on dorsal arms.
   3. Web formula: A>B>C>D>E.
   4. Single web nodule prominent on ventral side of each arm; located at sucker 34 (arm I), 30 (arm II), 28 (arm III) or 27 (arm IV).
   

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   Figure. Oral view of arm I of C. challengeri, holotype. Drawing from Collins (2003).

   5. Sucker count 63-72.
   6. Suckers cyclindrical, height similar to diameter (diameter 4.6% of head width).
   7. Maximum sucker diameter between suckers 30 and 38.
   8. Suckers more deeply embedded in in arms of females.
   9. Cirri long (mean maximum cirrus length from all individuals - 13.7% of head width).
   10. First cirri between suckers 4 and 7.
   

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   Figure. Lateral view of suckers and cirri of C. challengeri. Left - Female, 70 mm ML. Right - Male, holotype. Drawings from Collins (2003).

2. Shell
   1. Robust U-shape with nearly parallel outer walls of lateral wings.
   2. Inner and outer surfaces of saddle convex.
   3. Lateral wing terminates in two lobes.
   

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   Figure. Lateral (left), dorsal (middle) and ventral (right) views of the shell of C. challengeri, male, 75 mm ML. Drawings from Collins (2003).
   

Comments

Among other Atlantic species, Grimpoteuthis challengeri differs, where known, in having slender rather than broad gill lamellae. In addition it differs from:

• Grimpoteuthis boylei in the absence of a depression on the outer surface of the shell saddle, the absence of posterior salivary glands, egg size (13 mm vs 18-20 mm) and the number, form and arrangement of the suckers (Collins, 2003).
• Grimpoteuthis discoveryi in the shape of the shell wing (wing ends in one vs two lobes), the sucker number (63-72 vs 56-61), smaller sucker size in males (mean sucker diam./head width of 4.8 vs 6.4), longer cirri (2.5x in males, 3.5x in females vs 1.2x and 1.6x), generally 8 gill lamellae vs generally 7, and the presence of a radula (Collins, 2003).
• G. megaptera in the longer cirri (2.5x in males, 3.5x in females vs 2.0x) (Collins, 2003). This poorly known species cannot be reliably separated from G. challengeri.
• G. plena in the greater number of suckers (63-72 vs 55-60) and the longer cirri (2.5x in males, 3.5x in females vs 1.2-1.6x) (Collins, 2003).
• G. umbellata in the form of the gill lamellae (see aove), smaller sucker diameter (1.3 mm vs 2.2mm at arm I length near 100mm) and longer cirri (2.5x in males, 3.5x in females vs 1.2x) (Collins, 2003).
• G. wuelkeri in having generally 8 gill lamellae vs 6 or 7, a shell without a ridge on the outer surface of the saddle, longer cirri (2.5x in males, 3.5x in females vs 2.5x and 1.2x), no posterior salivary glands and a greater deph distribution (>4000 m vs <2100 m) (Collins, 2003).

Life History

Distribution

The type locality is Porcupine Abyssal Plain at 48°56'N, 15°45'W, and a depth of 4828-4838 m. This species is known only from the type locality and from an unknown locality somewhere in the Northwest Atlantic (Collins, 2002).

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.