Cirroctopus antarctica (Kubodera & Okutani, 1986)

Introduction

Characteristics

1. Shell

   Kubodera and Okutani (1986) describe the shell as follows: "The [shell] is broadly U-shaped. both rami, particularly at postero-lateral portion, are widened The posteriormost connective of both rami seems to be weaker than the remaining area." The original drawing is seen below and a recent photograph of the same shell is seen on the right.

   

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   Figure. The shell of C. antarctica, paratype. Left - Drawing from Kubodera and Okutani, 1986. Right - Photograph by T. Kubodera.

2. Pigmentation

   The title photographs suggests that the oral surface of C. antarctica has the same odd pigmentation as C. glacialis.

3. Measurements and counts

   Characters: Measurements in mm	Holotype	Paratype
   Sex	?	Female
   Mantle length	91; 94	180
   Mantle width	95; 69	135
   Head width	45	100
   Fin length	80; 67	70
   Fin width	40; 30	33
   Lengths and counts	Left/Right	Left/Right
   Arms I	200/200; 232/245	310/300
   Arms II	220/220; 253/255	310/280
   Arms III	225/220; 235/231	320/350
   Arms IV	220/215; 236/230	300/260
   Web sector A	110	140
   Web sector B	105/95	160/160
   Web sector C	110/100	150/160
   Web sector D	110/105	160/155
   Web sector E	55	110
   Arm I sucker counts (right; left/right)	72; 55/65	76
   Arm II sucker counts	73; 64/64	73
   Arm III sucker counts	69; 58/65	78
   Arm IV sucker counts	73; 55/63	55+

   Measurements and counts to the left of the semicolon are from Kubodera and Okutani (1986) and those to the right of the semicolon are from O'Shea (1999).

Comments

Kubodera and Okutani stated that this species differed from C. mawsoni by having subequal arms (this character would also separates it from all other members of the genus which have distinctly shorter ventral arms). The two octopods in the type series of C. antarctica were not in good condition and arm measurements can be very inaccurate. Arm size, however, remains a possible distinguishing character. The authors state that this species differs from C. glacialis by the shell which is very broad in posterolateral regions and the "well chitinized" beak. There appears to be no real difference in beak chitinization. The shell, however, does pose a problem. A photograph (see above) of the same gladius no longer, at least, appears to be distinctive as originally described but does seem to differ in some respects to the shell of C. glacialis (see that page). Unfortunately the degree of variation of the shell in both species is unknown. O'Shea (1999) considered this species to be a probable synonym of C. glacialis. We suspect that he is correct.

Distribution

References

Kubodera, T. and T. Okutani. 1986. New and Rare Cephalopods from the Antarctic Waters. Memoirs of National Institute of Polar Research, Special Issue, 44:129-143.

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

Vecchione, M., U. Piatkowski and A. L. Allcock. 1998. Biology of the cirrate octopod Grimpoteuthis glacialis (Cephalopoda; Opisthoteuthidae) in the South Shetland Islands, Antarctica. S. Afr. J. Mar. Sci. 20: 421-428.