Berryteuthis magister (Berry, 1913)

Berryteuthis magister: Holotype (153mm ML, 295mm TL), collected at Puget Sound, Washington, U.S.A. Photo from Berry (1912).

Introduction

B. magister was designated by Berry (1913) based on two large specimens from Puget Sound, Washington. Berry (1912）gave a detailed description, drawings and photos of these specimens as a different form of Gonatus fabricii in his "Cephalopods of western North America". Later he obtaind a true G. fabricii from the Irish coast in the Atlantic and considered that the Puget Sound specimens represented a new species and named it  Gonatus magister. Naef (1921) placed this species in a new genus Berryteuthis based on Berry's description, characterized by having large fines (FL>1/2ML) and no hooks on the clubs. Until Pearcy and Voss (1964) described B. anonychus from off Oregon, B. magister was the sole species of the genus Berryteuthis.

Diagnosis

A Berryteuthis with ...

• length to 42-43 cm ML and weight to 2.2-2.6 kg.
• large hooks present in medial series of arms I-III in large individuals of both sexes.

Characteristics

1. Arms
1. Arms stout, of moderate length (<60% ML), slightly unequal, II,III>I, IV.
   
2. Arm III = 62% ML.
3. Arm IV comprising 4 rows of suckers.
   
4. Arms I-III with 2 median rows of hooks and 2 marginal rows of suckers with long trabeculae.
   
   image info
   

   Figure. Armature of the arms of B. magister, holotype, 153 mm ML. Left - Side view of a hook from the distal region of arm III. Right - Oral-oblique view of the basal region of arm III. Drawings from Berry (1912)

2. Tentacles
   1. Stout and rather short, TL<ML.
      
   2. Tentacular clubs broadly expanded with well marked narrow dactylus and aboral keel.
   3. Club without hooks, with numerous minute suckers; suckers in median portion of manus much larger than in marginal areas.
   4. Locking apparatus, consisting of a series of small pads and suckers, along the entire dorsal margin of the club manus.
      
   image info

   Figure. Aboral and oral views of the tentacular club of B. magister, holotype, 153 mm ML. Drawings from Berry (1912).

   image info

   Figure. Aboral and oral views of the tentacular club of B. magister, holotype, 153 mm ML. Note locking apparatus on the upper margin in the top photograph. Photographs by R. Young (19 May '06).

3. Head
1. Head large, as broad as or a little broader than mantle opening.
   
2. Funnel broadly conical, funnel organ with inverted V-shaped pad with two ovate lateral ones.
   
3. Beaks. Information on the beaks of B. magister can be found here.
   
4. Radula with 7 longitudinal rows of teeth, central tooth tricuspidate, first lateral teeth bicuspidate, second and marginal teeth unicuspidate, horn-like.
   
   image info
   

   Figure. Radula of B. magister. Drawing from Sasaki (1929).

4. Mantle
   1. Mantle cylindrical and broad (MW=30% ML).
      
      
5. Fins and tail
1. fins large rhomboidal, Fl>50% ML, FW>FL.
2. mantle without distinct tail.
   
   
6. Photophores
1. no photophores externally and internally.
   

Comments

B. magister has been reported widely from the west coast of Oregon, northward to Alaska Bay, Aleutian and Kurile Islands, including the Bering Sea and the Sea of Okhotsk, down southward to the Sea of Japan and northeastern Honshu, Japan. Individuals living in the northern area tend to grow larger in size and attain up to 38 cm ML. Those large individuals have a little different external morphology and bodily proportions as well as tentacular club structures from the holotype described from near the southeastern border of their distribution (see distribution map).

image info

Figure. Berryteuthis magister (28cm ML) collected off Erimo, Hokkaido. Photo by Kubodera (2005)

Recently, two sub-species under B. magister have been reported from off Hokkaido (B. magister nipponensis Okutani & Kubodera, 1987) and the Sea of Japan (B. magister shevtsovi Katugin, 2000). These sub-species came from the southwestern border of the distribution of B. magister.  This indicates that the speciation of this group would be advanced in the southern peripheral regions of both east and west of their distribution, including the holotype.

Life History

Morphological change with growth of B. magister was reported by Kubodera and Okutani (1981). Paralavae of B. magister between 7 - 16 mm ML can be identified by having a stumpy bell-shaped mantle with small fins, large head with short, thick and stout arms and stout tentacles with 8-10 longitudinal rows of densely beset small suckers on the proximal portion of the immature clubs which are covered with minute sucker buds without a large central sucker bud.

image info

Figure. Morphological change with growth of B. magister. A: ventral view of a 9 mm ML specimen, B: dorsal view of a 12 mm ML specimen, C: tentacle of B, D: ventral view of a 16 mm ML specimen, E: tentacle of D. Drawings from Kubodera and Okutani (1981).

Paralarvae can be identified by the dorsal-head chromatophore pattern which is Type I,1 (three tear-shaped chromatophores on each side plus one additional chromatophore in the midline of the head.); the mantle has 20-25 dorsal chromatophores (Jorgensen, 2006)

image info

Figure. Dorsal views of the chromatophores of a B. magister paralarva, 8.5 mm ML, Gulf of Alaska. Left - Head. Right - Paralarva. Drawing from Jorgensen (2006).

Distribution

The distribution of B. magister is reported widely from subarctic waters in the North Pacific. It is especially abundant near the bottom off  the continental shelf (deeper than 300m). B. magister is an important bottom trawl catch for Russian fisheries in the western Bering Sea and in the Sea of Okhotsk.

image info

Figure. Distribution of B. magister. Dark pink area indicates known range; light pink area indicates inferred range. Chart modified from Okutani, et al. (1988). 

References

Berry, S.S. 1912. A Review of the Cephalopods of Western North America. Bulletin of the Bureau of Fisheries, 30(1910):267-336.

Berry, S.S. 1913. Notes on some West American cephalopods. Proceedings of the Accademy of Natural Sciences of Philadelphia: 72-77.

Jorgensen, E. M. 2006. Identification, distribution and relative abundance of paralarval gonatid squids (Cephalopoda: Oegopsida: Gonatidae) from the Gulf of Alaska, 2001-2003. Journ. Molluscan Studies. In Review.

Kubodera, T. and T. Okutani, 1981. The systematics and identification of larval cephalopods from the northern North Pacific. Research Institute of North Pacific Fisheries, Special Volume, 131-159 pp.

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.

Sasaki, M. 1929. A Monograph of the Dibranchiate Cephalopods of the Japanese and Adjacent Waters. Journal of the College of Agriculture, Hokkaido Imperial University, 20(supplement):357 pages.