Abraliopsis sp. B

Introduction

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Figure. Ventral view of Abraliopsis sp. B, male. Drawing by L. Burgess.

 Brief diagnosis:

An Abraliopsis (Abraliopsis) ...

• without dorsal flap on hectocotylus.
• with very broad head relative to ML (HWI, males - 45).
• with low numbers of hooks (11-14) on arms IV.
  

Characteristics

1. Arms
   1. Hectocotylus (right arm IV) with long, low, rounded-trapezoidal membrane on ventral margin from opposite hook 4-6 to 3/4 of arm length, then continues as indistinct ridge. No dorsal membrane present.
      
      

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      Figure. Dorso-oral view of the distal hectocotylized portion of right arm IV of Abraliopsis sp. B. Note the dorso-oral ridge has no modified membrane.Drawing by L. Burgess.
      

   

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   Figure. Hectoctylus of Abraliopsis sp. B, mature male, 19.5 mm ML. Top - Dorsal view showing no dorsal membrane. Bottom - Ventral view.
   

   2. Arms IV relatively short. Arms IV length index - 59-84 (x̅ = 74.4, n = 14).
   3. Number and sizes of hooks not different between sexes; 13-21 hooks on arms I, 14-24 hooks on arms II, 14-22 hooks on arms III, 11-14 hooks on arms IV (x̅ = 12.5, n= 14); hooks on arms IV smallest.
      
   4. Arm tips with 14-26 suckers; generally arms III with fewest suckers, arms I with most. Largest arm suckers with three blunt teeth distally on inner rings, otherwise smooth.
      
      

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      Figure. Oral and lateral views  of a arm IV arm hook of Abraliopsis sp. B (left two images) and an oral view of a large arm-tip sucker (right image). Drawings by L. Burgess.
      

2. Tentacles
   1. Club with 2 series of usually 3-4 hooks each; largest hooks of ventral series over 3 times length of counterparts of dorsal series and laterally compressed. Inner sucker rings of dactylus smooth.
      
   2. Club with large keel and carpal flap.
      
      

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      Figure. Images of the club of Abraliopsis sp. B. Left - Oral (left) and ventral (right) views. Photographs by R. Young. Right - Oral view. Drawing by L. Burgess.
      

3. Head
   1. Occipital folds: 4 folds or either side of head. Typically, fold 1 (ventral-most fold) barely recognizable; fold 2 with tongue-like olfactory papilla; fold 3 recognizable; fold 4 only apparent in large individuals. The posterior connection between folds 3 and 4 generally undetectable but barely detectable in squid in excellent condition (see below).
      
      

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      Figure. Side view of the head of Abraliopsis sp. B, male, 21 mm ML. Occipital folds 3 and 4 are indicated by marked black arrows. The white arrow points to the just-barely-detectable posterior connection between the two marked folds.

   2. Head very wide relative to mantle length. Head width index - Males: 40.9-50 (x̅ = 45.4, n=4); Females: 40-42.9(x̅ = 40.5, n = 4).
      
4. Mantle
   1. Mantle short and broad (MWI 40).
5. Fins
   1. Fins large. Fin length index - 60-80. Fin width index - 100-115 (x̅ = 106.4,
      n = 8) .
      
6. Photophores
   1. Ocular photophores, characteristic of most Abraliopsis spp., with 5 photophores with terminal photophores at either end slightly enlarged (<2 X adjacent photophores).
      
      

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      Figure. Occular photophores of Abraliopsis sp. B. Drawing by L. Burgess.

   2. Integumental photophores: Head and mantle with scattered photophores.
      
      

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      Figure. Abraliopsis sp. B showing photophore arrangement. Left - Ventral view. Right- Same view, same squid, drawing from photograph with colored dots representing photophores. Red dots - Complex photophores. Blue dots - Non-complex photophores. Images by R. Young.

      
      A more detailed look at the photophore pattern can be seen here.
7. Viscera
   1. Female: One spermatangial receptacle under dorsal part of collar muscle on either side of nuchal cartilage (= Dorsal-Collar Pocket). No Stellate Pocket posterior to nuchal cartilage, between stellate ganglia, where gladius abuts visceral mass.
      
      

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      Figure. Dorsal view of Abraliopsis sp. B with the mantle folded posteriorly to reveal the pigmented spermatangiia receptacles. The collar on the right side of the squid has been partially cut away to show the attached spermatangia.The white material anterior to the attachments sites seems to be a preservation artifact. Photograph by R. Young.
      

8. Measurements and counts:

   	TC 7, sta. 10	TC 7, sta. 10	TC 32, sta. 28	TC 32, sta. 18	TC 32, sta. 18	TC 32, sta. 18	TC 7, sta. 10	TC 32, sta. 8	NEC 2017, M1057-01
   Sex	Male	Male	Male	Male	Female	Female	Female	Female	Female
   Mantle length	20	20	22	22	21	23	25	25	24
   Head width index	50	45	46	41	43	39	40	40	51
   Fin Length index	60	75	73	68	74	77	80	76	71
   Fin width index	110	115	100	100	110	100	104	112	104
   Arm Length, I	50	50	41	46	48	48	48	36
   II	55	55	46	50	52	52	56	40
   III	55	60	46	50	52	52	52	44
   IV	80/80	70/75	59/-	73/73	76/76	76/76	80/84	64/-	79/79
   No. hooks, I	19	10	18	18	14	19	20	20	19/20
   II	20	21	18	19	17	21	21	16	22/20
   III	19	19	18	21	16	22	20	19	18/18
   IV	12/12	13/13	11/-	13/13	12/13	13/14	12/12	12/-	12/12
   Club length index	25	30	21	23	24	30	28	20	22/24
   Club hooks	3/4; 4/3	3/4;4/3	3/3; 4/4	4/4; 3/3	3/5; 3/4	5/4; 4/4	3/4; 4/3	4/4; -	5/5; 5/4
   Carpal suckers	5/5	4/4	4/4	4/4	4/4	5/5	4/4	4/-	-/-

Comments

Comparisons of Abraliopsis sp. B to other members of the subgenus can be found on the Abraliopsis (Abraliopsis) page.

Life History

The development of paralarvae of Abraliopsis sp. B was examined by (Young and Harman, 1985) by hatching eggs collected in the plankton and rearing the hatchlings until all yolk had been utilized (usually 6 days). Older stages were identified by following a morphological series to a size that showed species-specific features.

Eggs not examined.

Mantle chromatophore pattern of hatchlings is diagnostic (see figure below). The distinctive transversely elongate two chromatophores posterior to each eye on ghe ventral surface of the head are present at 2.0 mm ML. Net captured paralarvae generally lose chromatophores due to damage. Terminal arm IV photophores first appear as slight swellings at 4.0 mm ML. Appearance similar to Abraliopsis sp. A but broader and more heavily pigmented in the advanced stages.

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Figure. Ventral and dorsal views of various sizes of paralarvae of Abraliopsis sp. A, Hawaiian waters.  Scale bars - 1.0 mm. Drawings from Young and Harman (1985).

Distribution

References

Young, R. E. 1978. Vertical distribution and photosensitive vesicles of pelagic cephalopods from Hawaiian waters. Fish. Bull., 76: 583-615.

Young, R. E. and R. Harman. 1985. Early life history stages of enoploteuthin squids (Cephalopoda, Teuthoidea, Enoploteuthidae) from Hawaiian waters. Vie et Milieu, 35: 181-202.