Cirrothauma magna (Hoyle, 1885)

Introduction

C. magna is a large (up to 1200 mm TL) but fragile deep-sea cirrate that is known from 4 specimens captured from the Atlantic, Pacific and Indian Oceans.

Diagnosis

A Cirrothauma ...

• with normal eyes bearing lenses. 

Characteristics

1. Eyes
   1. Functional eyes (eyes with lenses).
   image info

   Figure. Eye of C. magna, male, 220 mm ML. At the far right of the drawing is the optic stalk that enters the optic lobe of the brain. From this the optic nerves pass through the white body and into the eyeball. Drawing from Guerra, et al., 1998.

2. Suckers
   1. Arms with 3 types of suckers (top figure; bottom figure shows the two more distal types).
   2. Suckers nearest mouth: small, cyclindrical, closely spaced, with stout stalk.
   3. Following suckers: larger and on long stalks; thin, broad, infundibulum with small openings (acetabulum, apparently, nearly absent); infundibulum can inflate or deflate to form a spherical (see middle sucker in bottom drawing), flattened or "half-closed eyelid."
   4. Suckers of distal third of arm: large, fleshy with bowl-like, amphora-like or barrel-like shape; sessile with rigid, muscular base (however see top figure where these suckers have long stalks).
   image info
   image info

   Figure. Top - Three sections of the arm, submature female of C. magna, 140 mm ML. Bottom - Two sections of the arm, mature male, 220 mm ML. Drawings from Guerra, et al., 1998.

3. Web
   1. Distal web attachments to each arm asymmetrical.
   2. Web nodules absent.

Comments

The above description is taken from Guerra et al., 1998. Additional features of the description can be found here.

Nomenclature

C. magna was traditionally placed in Cirroteuthis although Robson (1932) and Nesis (1987) questioned this placement. O'Shea (1999) noted the similarity of the shell to that of Cirrothauma and moved the species to that genus.

Hoyle (1886) described a second but mutilated specimen along with his redescription of the holotype. Robson (1932) suggested that this second specimen belonged to a separate species which he named Cirroteuthis hoylei. The status of this latter species is uncertain.

Distribution

The specimens described by Guerra, et al. (1998) were taken at 15°29'N, 46°34'W in the central North Atlantic (male) and 23°00'N, 17°34'W in the North Alantic off West Africa (female).

O'Shea (1999) suspects that a specimen taken off New Zealand at 39°58'S, 178°02'E, 1450-1468 m, represents a new species.

References

Guerra, R., R. Villanueva, K. N. Nesis and J. Bedoya. 1998. Redescription of the deep-sea cirrate octopod Cirroteuthis magna Hoyle, 1885, and considerations on the genus Cirroteuthis (Mollusca: Cephalopoda). Bull. Mar. Sci., 63: 51-81.

Hoyle, W. E. 1886. Report on the Cephalopoda. Rept. Sci. Res. Challenger. 16 (44): 246 pp.

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