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Containing group: Pterygioteuthis

Introduction

Brief Diagnosis:

A Pterygioteuthis with... 

• hooks in a single, ventral series on arms I-III.
• tentacular club suckers on manus with dorsal series enlarged.
• eyes each with 10 large and 4 minute photophores.
  

Characteristics

1. Arms - hooks in 1 series (ventral) on arms I-III.
   
   

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   Figure.  Oral view of an arm III from a female P. gemmata. ©

   1. Arms I - distal suckers are normal in appearance.
      
      

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      Figure. Oral view of left arm I from a male P. gemmata (several suckers missing from dorsal series). ©

   2. Arms IV - males and females with suckers in 2 series; location and size vary with sex and species.
      
      

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      Figure.  Oral views of right arms IV from P. microlampas.  Top - female.  Bottom - male (Note - sucker series can start near base, at midpoint, or more distal along arm).  ©

   3. Hectocotylus plate - contains many small teeth
      
      

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      Figure.  Side view of the hectocotylus plate from P. microlampas. ©

2. Tentacular clubs - suckers (4 series) on manus with dorsal series enlarged.
   
   

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   Figure.  Oral view of a tentacle club from P. microlampas. ©
3. Buccal membrane - with irregular papillae on inner surface.
   
   

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   Figure.  Oral view of the buccal membrane (and associated papillae) from P. microlampas. ©

4. Eye photophores - 10 large and 4 minute (see arrows below).
   
   

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   Figure.  Small eye photophores from the left eye of P. microlampas. ©

Discussion of Phylogenetic Relationships

Pterygioteuthis gemmata and P. microlampas are morphologically similar: both possess 4 small photophores on the eye, 4 tentacular photophores, and a hectocotulys plate with many small teeth.  Historically there has been substantial debate over whether P. microlampas is a distinct species or a subspecies of P. gemmata, but authors have been reluctant to synonymize the two given that some morphological and biogeographical differences exist (e.g. Riddell, 1985; Young, 1972).  Lindgren (2010) found P. microlampas most easy to distinguish from P. gemmata by its relatively smaller size (mature specimens P. gemmata have a gladius length greater than 17mm) and by the fewer number of hooks on arms III (P. microlampas generally has less than 4 hooks). 

Distribution

Members of the Pterygioteuthis gemmata group appear to occupy fairly distinct geographic regions.  P. microlampas has been found both in waters off the Hawaiian Islands and New Zealand (Riddell, 1985), but not in the open ocean.  However, this sampling bias may be due to the lack of sampling in the open ocean between Hawaii and New Zealand.  P. gemmata is found in temperate waters throughout the Atlantic.  In the Pacific, P. gemmata is found in large numbers off the coast of Southern California (Okutani, 1974) and Baja but does not occur in the eastern tropical Pacific (Lindgren, 2010).

 

References

Lindgren, A.R. 2010. Systematics and distribution of the squid genus Pterygioteuthis (Cephalopoda: Oegopsida) in the eastern tropical Pacific Ocean. Journal of Molluscan Studies, 76(4): 398-398.

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.

Riddell, D.J. 1985. Enoploteuthidae of New Zealand. Fish. Res. Bull. New Zealand. 27:1-52.