Galiteuthis glacialis (Chun, 1906)

Introduction

Galiteuthis glacialis is a moderately large cranchiid squid, from Antarctic waters, reaching about 0.5 m ML.

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Figure. Dorssal view of G. glacialis. Photograph by M. Vecchione.

Diagnosis

• Two linear, multicuspid tubercules at each funnel-mantle fusion.
• Two to three small, conical tubercules/cusps on either side of nuchal head-mantle fusion.
  

Characteristics

1. Mantle tubercules
   1. Mantle-funnel fusion: Two elongate tubercules on each side of fusion with 2 or 3 cusps each (upper drawing).
   2. Mantle-nuchal fusion: Two small tubercules with 2-3 cusps on each side (lower drawing).
   3. Mantle surface: Rough with many rounded, cartilagenous tubercules in subadults (both drawings).
      

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      Figure. Anterior mantle and head of G. glacialis, 333 mm ML, female. Left - Ventral view  showing tubercules at funnel fusion. Right - Dorsal view showing tubercules at nuchal fusion, same specimen. Drawings from Sweeny (1978).

2. Tentacles
   1. Club with 10-12 hooks in subadults.
   2. Club manus with small lateral suckers.
      

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      Figure. Oral view of tentacular club of G. glacialis, 297 mm ML, male. Drawing from Sweeny (1978).

Comments

The easiest means of identification is by the unusual arrangement of tubercules at the funnel and nuchal fusions, and the Antarctic habitat.

More details of the description can be found here.

Nomenclature

Galiteuthis aspera Filippova, 1972 from the Scotia Sea, Antarctic waters, is a junior synonym of this species (McSweeny, 1980).

Life History

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Figure. Ventral views of G. glacialis. Top - 11 mm ML paralarva. Bottom - 54 mm ML juvenile. From Voss, 1980, printed with the Permission of the Bulletin of Marine Science.

The 11 mm paralarva (drawing on right) shows eyes on short stalks and extremely small, widely separated fins. At about 5-6 mm ML tubercules at the nuchal fusion can be detected. At 7 mm ML the tubercules at the funnel fusion can be detected. At 30 mm ML a well delineated club is present that bears four series of suckers.

At 54 mm ML the young G. glacialis (drawing on right) has eyes that have just become sessile and fins that approach that of the adult in shape (i.e. longer than wide). At 55-65 mm ML the hooks begin to develop on the tentacular clubs and well-formed hooks are present by just over 100 mm ML. At just over 100 mm ML tubercules can be detected on the mantle. At about 125 mm ML the ocular photophores are fully developed.

Distribution

The type locality is listed by Chun (1906) as "Antarctic." The distribution of this species is found throughout the circum-polar Antarctic waters where it is one of the most abundant squids (Nesis, 1982). A map from the British Antarctic Survey showing the distribution can be seen here.

References

Chun, C. 1906. System der Cranchien. Zool. Anz., 31: 82-86.

McSweeny, E. S. 1978. Systematics and morphology of the Antarctic cranchiid squid Galiteuthis glacialis (Chun). Antarctic Res. Ser., 27:1-39.

Nesis, K. N. 1982. Abridged key to the cephalopod mollusks of the world's ocean. 385+ii pp. Light and Food Industry Publishing House, Moscow. (In Russian.). Translated into English by B. S. Levitov, ed. by L. A. Burgess (1987), Cephalopods of the world. T. F. H. Publications, Neptune City, NJ, 351pp.

Voss, N. A. 1980. A generic revision of the Cranchiidae (Cephalopoda; Oegopsida). Bull. Mar. Sci., 30: 365-412.