Abraliopsis affinis (Pfeffer 1912)

Introduction

A. affinis is one of the more easily recognized members of the subgenus. Males reach a length of at least 35 mm ML and females a length of 43 mm ML. This species is restricted in its distribution to the Eastern Tropical Pacific.

Brief diagnosis:

An Abraliopsis (Pfefferiteuthis) with ...

• key-hole shaped, bare region (lacks photophores) on  anteroventral mantle.
• long gaps separate photophore patches on Lateral Arm IV Series and Arm III Series.
  
• 3 red photophores in caret at posterior end of Median Head Series.

Characteristics

In addition to familial characters (listed on the Enoploteuthidae page) and generic characters (listed on the Abraliopsis page), Abraliopsis affinis has:

1. Arms
   1. Arms IV about 75% of ML.
   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.
   4. Hectocotylus (right arm IV) with two subequal-sized offset flaps.
   5. Protective membrane and with elongate spatulate trabeculae very large on left arm IV, and with small, conical tubercules on trabeculae.
   6. Oral base of arms I-III with conical tubercules.
   7. Trabeculae of arms I well developed in protective membranes on both margins; small tubercules along oral margins of trabeculae. 
   8. Arms II & III with much larger trabeculae in membranes of ventral than dorsal margins; tubercules absent from trabeculae.
   9. Arms III in males with proximal 5 or more suckers on dorsal margin much larger than counterparts on ventral margin. Proximal sucker of the ventral series small and equal in size to next ventral hook (see photograph below).
      
   10. Largest suckers of distal arm with about 6 truncated teeth on distal margin; arms I with most suckers (~26) and arms III the least (~9). LB
       
   

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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).

   

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   Figure. Oral views of the arms of A. affinis, mature male, 30 mm ML, off Baja California. Photographs by R. Young.

2. Tentacle clubs
   1. Manus with large ventral hooks about 2.5 times height of dorsal counterparts..
   2. Carpal flap and aboral keel, large.
   3. Three or four hooks in each series.
      
   

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

   

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    Figure. Various oral (left) and aboral (right) views of the tentacular club of A. affinis, mature male, 33 mm ML, off Baja California. Photographs by R. Young.

3. Photophores
   1. Ocular photophores: 5 photophores with terminal photophores about 2X diameter of adjacent ones.
      
   2. Integumental photophores: 3 series on venral head; 6 poorly defined series on mantle with some scattered red photophores.
      
      

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      Figure. Ventral views of the integumental photophores of A. affinis, mature male, 33 mm ML. Left - Photograph of preserved squid. Right - Outline drawing from photograph with all integumental photophores represented by colored dots.  Red dots - Complex photophores. Blue dots - Non-complex photophores. Images by R. Young.

      Detailed information on the integumental photophores can be found here.

4. Viscera
   1. Spermatangia receptacles - Females with three pockets for storing spermatangia: A Stellate Pocket at the junction of the anterior end of the gladius and the visceral mass, and between the stellate ganglia; two Dorsal-collar Pockets on the inner surface of the collar at its anterodorsal end.
      
      

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      Figure. Dorsolateral view of the spermatangial receptacles of A. affinis, mature female, 25 mm ML, showing attached spermatangia. Photograph by R. Young.
      

Comments

Comparisons of all species in the subgenus can be found on the Abraliopsis (Pfefferiteuthis) page.

Distribution

Geographical Distribution

This species is distributed in the tropical East Pacific between 20° N and 20° S (Okutani, 1974; Alexeyev, 1995), westward 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.