Pterygioteuthis microlampas Berry 1913

Introduction

Pterygioteuthis microlampas and P. gemmata are very similar but are most easily separated by the smaller size of adult P. microlampas and fewer number of hooks on the arms of males of this species (Riddell, 1985).

Characteristics

1. Arms
   1. Hectocotylus (left arm IV) plate with many small teeth.*
      image info

      Figure. Upper left - P. gemmata toothed plates from the hectocotylus of two males from off California (redrawn from Young, 1972) and from one male from off New Zealand (redrawn from Riddell, 1985).  Bottom left - P. microlampas toothed plates from two males from off New Zealand (redrawn from Riddell, 1985). Right - A cleared hectocotylus of P. microlampas from Hawaiian waters showing the toothed plate. Black dots throughout the arm tissue are artifacts. Photograph by R. Young.

   2. Arms I, II and III with hooks in ventral series only.*
   3. Arms IV of males and females with suckers.*
   4. 6-12 hooks on combined lateral arms (arms II and III on one side) in males.
   image info

   Figure. Side view of a portion of Arm II of P. microlampas, preserved and cleared, showing suckers and hooks. Note double cusps on hooks. Tiny balls are artifacts. Photograph by R. Young

2. Photophores
   1. Tentacles with four embedded photophores.*
   2. Eye with 10 large (9 visible on left eye of photograph) and four small photophores (visible on right eye of photograph).*
   image info

   Figure. Ventrolateral view of the head, arms and tentacles of a preserved and cleared P. microlalmpas (18 mm ML, female, off Hawaii). The white tentacular photophores are clearly visible on both tentacles. The only ocular photophore that cannot be seen is the one posterior to the lens. Photograph by R. Young.

3. Size
   1. Females mature at 18-20 mm ML; males at 17 mm ML (Riddell, 1985).
   2. Maximum length about 23 mm ML.

* Characters shared with P. gemmata.

Life history

image info

Figure. Ventral view of paralarval P. microlampas, 2.9 mm ML. Drawing modified from Young, et al., 1992.

Paralarvae

Young paralarvae are most easily recognized by:

1. Large, dark chromatophore at the base of the tentacular club.
2. Small size of the ocular photophores.
3. Pair of chromatophores of the ventral surface of the funnel (present only in advanced paralarvae; colored grey in the illustration as it is hidden beneath the mantle).
4. Numerous chromatophores on the mantle.

Although paralarvae are easily damaged in plankton nets, character number 1 is usually apparent. Compare with paralarvae of Pterygioteuthis giardi and Pyroteuthis addolux.

Distribution

Vertical distribution

In Hawaiian waters P. microlampas is found mostly between depths of 450-500m during the day and 50-100 m at night (Young, 1978).

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Figure. Vertical distirbution of P. microlampas, Hawaiian waters. Yellow dots - Modal depth of trawl, day capture. Blue dots - Modal depth of trawl, night capture. Bars - Depth range of trawl. Chart modified from Young, 1978.

Geographical distribution

This species was first described from Hawaiian waters (Berry, 1913) and has since been reported from waters near New Zealand north of the tropical convergence (ca. 28° S. Lat.). At this locality it barely overlaps with the more southernly P. gemmata as seen in the data from Riddell (1985).

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Figure. Geographical distribution of Pterygioteuthis spp. near New Zealand. Yellow circles represent captures of P. gemmata and white triangles captures of P. microlampas. Chart modified from Riddell, 1985.

The world map shows some of the general localities (white circles) where P. microlampas has been captured. Localities where pyroteuthids, other than this species, have been captured are represented by yellow crosses. Only one record per general locality is included (records listed here). P. microlampas presumably occurs throughout much of the tropical Pacific but seems to be absent from the Eastern Tropical Pacific. No regional differences in taxonomic characteristics are known.

image info

Figure. Geographical distribution of P. microlampas (white circles).

References

Berry, S. S. 1913. Diagnoses of new cephalopods from the Hawaiian Islands. Proc. U. S. Nat. Mus. 37: 407-419.

Riddell, D. J. 1985. Enoploteuthidae of the New Zealand Region. Fisheries Research Bulletin. New Zealand Ministry of Agriculture and Fisheries, No.27: 1-52.

Young, R. E., K. M. Mangold and M. Vecchione. 1992. The enoploteuthid group of families. P. 55-66. In: Sweeney, M. J., C. F. E. Roper, K. M. Mangold, M. R. Clarke and S. V. Boletzky (Eds.). "Larval" and juvenile cephalopods: A manual for their identification. Smithson. Contr. Zool. No. 513.