Abraliopsis sp. NC2

Introduction

Abraliopsis sp. NC2 is presently known only from waters near New Caledonia. Females reache at least 39 mm ML.

Brief diagnosis:

An Abraliopsis (Micrabralia) ...

• with small keels on tentacular club but without carpal flaps.
• without tubercules on arms of males.
• with hooks throughout arms IV (except hectocotylus).
• with many blue photophores in Medial Head Sector.
  

Characteristics

1. Arms
   1. Hectocotylus: Right arm IV with long ventral semilunar flap and overlapping shorter (about half length of ventral membrane) dorsal semilunar flap. Low protective membranes present proximal to flaps. Hooks extend to proximal end of dorsal membrane; distal portion bare of suckers and hooks.
      
      

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      Figure. Two views of the hectocotylus of mature males of Abraliopsis sp. NC2. Top - Oral view, 23 mm ML. Bottom - Dorsal view, 22 mm ML. Photographs by R. Young.

   2. Arms I-III with two series of hooks, replaced by suckers at tips of arms
      
   3. Arms of males without tubercules. Arms III of males without modification of basal hooks.
      
   4. Left arm IV in males and both arms IV in females with hooks virtually to terminal large photophores.
      
   5. Arms I-III (both sexes) with well-developed tabeculate membranes on ventral margins and virtually none on dorsal margins.
      
   6. Arms IV (females) with trabeculate membranes on both margins proximally, with ventral membranes larger (but much smaller than counterparts of arms III); membranes diminish distally. Left arm IV of males with low trabeculate membranes on ventral margin proximally but without obvious membranes on dorsal margin.
      
   

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   Figure. Arms IV of Abraliopsis sp.NC2 showing distribution of hooks.  Photographs by R. Young.
   

2. Tentacles
   
   1. Club manus with 6 hooks in two series, suckers in one partial series.
   2. Club with low, short keel and without carpal flap.
      
   3. Largest hooks of club ventral series more than 3 times height of counterparts in dorsal series.
   4. Hook claws of club laterally compressed in cross-section.
      
   

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   Figure. Tentacular clubs of Abraliopsis sp. NC2, male, 23 mm ML. Top - Dorso-oral view. Note the low but distinct keel but no carpal flap. Bottom - Oral view.  Note the laterally compressed structure of the hook claws.  Photographs by R. Young.

3. Head
   1. Well developed posterior cresent ridge between occipital lobes 3 and 4.
      
      
4. Photophores
   1. Ocular photophores: 5 photophores with end members about 2X width adjacent photophores.
      
   2. Integumental photophores: Ventral head with red photophores in 3 series and ventral mantle in 6 series with scattered blue photophores between.
      

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      >

      Figure. Ventral view of Abraliopsis sp. NC2, mature male, 22 mm ML. Left - Photograph of the preserved squid. Photophore patterns can be difficult to determine at first glance. 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.

      More details of the integumental photophore pattern can be seen here.
      

5. Viscera
   1. Females with 3 spermatangia receptacles: Two dorsal-collar pockets, one stellate pocket.
      
      

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      Figure. Spermatangia receptacles of Abraliopsis sp. NC2, female, 36 mm ML. Top - Dorsal view showing the pigment (arrows) indicating the presence of three receptacles. Bottom left - The anterodorsal mantle pulled back to reveal the stellate pocket reveals little. However, a narrow slit (arrow) indicates the presence of the pocket. Bottom right - Fused part of mantle cut away reveals a typical pigmented, conical, stellate pocket (arrow). Photographs by R. Young.
      

6. Measurements and counts.
   

   	NEC-2013, M049-01	NEC-2013, M049-01	NEC-2010, M043-02	NEC-2013, M049-01	NEC-2017, M057-01
   Sex	Male, mature	Male, mature	Male, mature	Female, mated	Female, mated
   Mantle length	22	24	22	27	39
   Head width index	-	-	-	-	33
   Fin Length index	69	69	72	68	73
   Fin width index	110	106	110	107	97
   Arm Length index (R/L): I	72/67	63/63	74/64	-	55/52
   II	87/87	80/78	75/-	-	67/64
   III	72/74	-/73	78/72	-	56/62
   IV	92/90	98	84/96	-	78/72
   No. arm hooks (R/L): I	15+/-	-/17	19/17	-	17/17
   II	20/-	-/21	18/-	-	20/18
   III	-/17	-/-	17/17	-	19/18
   IV	21/28	20/27	21/29	21/20	23/24
   Club length index (R/L)	-	-/28	26/-	-	-
   Club hooks (D/V)(R:L)	-	-; 3/3	3/3; -	-	-
   Carpal suckers (R/L)	-	-	-	-	-

Comments.

Abraliopsis (Micrabralia) sp. NC2 has no unusual features but, nevertheless is very different from all other members of the subgenus. It is similar to the sympatric A. (M) sp. NC1 in the general patterns of integumental photophores but differs in details:

• Number of red photophores in  the caret of the Median Head Series (5 vs 3).
• Number of red photophores in the Lateral Patch of the funnel (2 vs 1).
• Number and arrangement of red photophores in the Medial Patch of the funnel (4 vs 3; "nose" pattern vs straight line).

Among the other features that separate these two species, the easiest to use is the absence of armature on the distal 1/3 - 1/2 of both arms IV in A. (M) sp. NC1.

The NC species were frozen prior to fixation which makes detection of photophore types, arm membranes and trabeculae difficult and, probably, with more errors in description.

See the Abraliopsis (Micrabralia) page for comparisons among all species of the subgenus.

Distribution

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Figure. Distribution of Abraliopsis sp. NC2. White dots represent the capture localities. Base map from Google Earth.app.