Abraliopsis affinis (Pfeffer 1912)

Introduction

Characteristics

1. Tentacle clubs
   1. Two rows of different-sized hooks on manus.
   2. Carpal flap and aboral keel distinct.
      
   

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   Figure. Oral view of the tentacle club of A. affinis, male, tropical East Pacific. Drawing From Okutani (1974).

2. Arms
   1. Arms IV relatively long.
   2. Arms I-III with 15 - 30 hooks and distal suckers.
   3. Female with ca.25 hooks on arm IV; male with ca. 30 hooks on hectocotylized arm (right arm IV) and ca. 40 hooks on modified left arm IV.
      
      
3. Hectocotylus and male sexual dimorphism
   1. Hectocotylus with two subequal-sized offset flaps.
   2. Modified portion without armature.
   3. Protective membrane and its spatulate trabeculae well developed on left arm IV, web-like; with minute conical papillae on trabeculae.
   4. Oral surface of arms I-III ornamented with numerous small conical papillae.
      
   

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   Figure. Oral views of arms IV of A. affinis, male, tropical East Pacific. Left - Modified left arm. Right - Hectocotylus. Middle - Dorsal view of the modified region of the hectocotylus. Drawing From Okutani (1974).

4. Integumental photophores
   1. Ventral mantle with six narrow longitudinal stripes of large integumental organs and with scattered intermediate small organs between stripes; wide mid-ventral photophore-less strip is distinct on anterior half of ventral mantle.
   2. Ventral head with three rows of narrow, longitudinal stripes and some intermediate scattered organs between stripes.
   3. Narrow stripes of organs along ventral side of arm III and dorsal side of arm IV are interrupted.

Distribution

Geographical Distribution

This species is distributed in the tropical East Pacific between 20° N and 20° S (Okutani, 1974; Alexeyev, 1995), eastward at least to 126° W (Nesis, 1982/87).

References

Alexeyev, D.O. 1994. New data on the distribution and biology of squids from the southern Pacific. Rutenica, 4:151-166.

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.

Okutani, T. 1974. Epipelagic decapod cephalopods collected by midwater tows during the EASTROPAC Expedition, 1967-1968 (systematic part). Bull. Tokai Reg. Fish. Res. Lab., 80:29-118.