Abralia astrosticta Berry 1909

Introduction

A. astrosticta is a relatively large species in the genus attaining 70mm DML.  This species is a component of mesopelagic boundary community in Hawaiian waters (Reid et al., 1991).

Brief diagnosis:

An Abralia (Astrabralia) with ...

• indistinct longitudinal strips of photophores on mantle and head.

Characteristics

1. Tentacles
   1. Clubs with about four hooks on ventral side.
   2. Club manus with two rows of large suckers on dorsal side.
   

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   Figure. Oral view of the tentacular club of A. astrosticta, Hawaiian waters. Drawing from Tsuchiya (2000).
   

2. Arms
   1. Right ventral arm of male hectocotylized.
   2. Hectocotylus with two subequal sized off-set flaps.
      
      
3. Head
   
   1. Beaks: Descriptions can be found here: Lower beak; upper beak.
      
      
4. Photophores
   1. Eye photophores
      1. Five large silvery organs subequal in size.
         
         
   2. Integumental Photophores
      1. Ventral mantle with scattered arrangement of organs forming very indistinct longitudinal strips.
      2. Ventral head with three indistinct, longitudinal stripes of organs.
      3. Large class of integumental photophores unusually large.
         
      

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      Figure. Ventral view of the head and mantle photophores of A. astrosticta, 48 mm ML, immature female, Hawaiian waters, preserved. Photograph by R. Young.

   3. Terminal Arm Photophores
      1. Arm IV with four large ovoidal photophores at tip and photophores not encased in chromatophores.
      2. Terminal suckers lost on oral side of arms IV opposite photophores  in both sexes.
      

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      Figure. Ventral view of an arm IV of A. astrosticta, immature male, Northwest Pacific, showing the large terminal photophores (arrows). Drawing from Tsuchiya and Okutani (1989).

   4. Caudal Photophores
      1. Near mantle apex, a pair of ovoidal photophores buried in tissue.
      

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      Figure. Caudal photophores of A. astrosticta. Left - Side and ventral views of, presumably, a mature squid. Drawings from Tsuchiya and Okutani (1989). Right - Ventral and slightly oblique view of the right caudal photophore (arrow), immature female. Photograph by R. Young.

Comment

The large photophores at the tips of arms IV, which is shared with A. asrolineata, is similar to the arrangement in genus Abraliopsis except that they are somewhat smaller and lack the black chromatophores that completely surround the photophores in Abraliopsis (In Abraliopsis the chromatophores, of course, retract during light emission).

Life history

Paralarvae

Paralarva of present species is characterized by:

• Integumental photophores very large.
• Caudal photophores barely apparent at 3.2mm ML.

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Figure. Ventral and dorsal views of A. astrosticta, Hawaiian waters. Scale bar is 1 mm. Note that the caudal photophores are detectable in both paralarvae. Drawings from Young and Harman (1985

(Young and Harman, 1985)

Distribution

Vertical distribution

A. astrosticta is a member of the mesopelagic boundary community in Hawaiian waters (Reid et al., 1991; Young, 1995). Adult specimens were caught at the bottom in 110 and 180m in Hawaii by gillnet and shrimp trawl. Juveniles were caught between 10 and 130m deep at night near Hawaii by pelagic trawls (Young, 1978).

Based on this sparse data, A. astrosticta is thought to inhabit near-bottom waters during the day at upper mesopelagic depth or shallower (i.e., waters with relatively high light levels) as indicated by the large size of their ventral photophores. At night they move into shallower waters, and presumably, move further off the ocean floor (Young, 199? ****)

Geographical distribution

This species was first described from Hawaiian waters. Distribution of the species includes the Ryukyu Islands (Tsuchiya, 1993), the Philippine Sea (Nesis and Nikitina, 1988), Hawaiian waters (Young, 1978; Burgess, 1992), New Zealand and western North Australia (Riddell, 1985; Lu and Philipps, 1985), and eastern North Australia.

References

Burgess, L.A. 1991. Squids of the Genus Abralia (Cephalopoda) from the Central Equatorial Pacific with a Description of Abralia heminuchalis, New Species. Bulletin of Marine Science, 49(1-2)(1991):113-136. [Published 29 January 1992]

Lu and Philipps, 1985. Nesis,K.N. and I.V. Nikitina. 1987. Redescription of Abralia steindachneri and Revision of Subgeneric Systematics of the Genus Abralia (Cephalopoda, Enoploteuthidae). Zoologichesky Zhurnal, 66(11):1693-1705.

Reid, S. B., J. Hirota, R. E. Young and L. E. Hallacher 1991 -- Mesopelagic-boundary community in Hawaii: micronekton at the interface between neritic and oceanic ecosystems. Mar. Biol. 109: 427-440.

Tsuchiya, K. 1993. Distribution and zoogeography of the family Enoploteuthidae in the Northwest Pacific. In: Okutani, T., O’Dor, R. K. and Kubodera, T. (eds.) 1993. Recent advances in fisheries biology (Tokai University Press. Tokyo). pp. 571-585.

Tsuchiya, K. 2000. Illustrated book of the Enoploteuthidae. In: Okutani T., ed. True face of Watasenia scintillans. Tokai University Press, Tokyo, p 196–269. (in Japanese)

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

Young, R.E. 1995. Aspects of the natural history of pelagic cephalopods of the Hawaiian mesopelagic-boundary region. Pacific Science, 49:143-155.