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Abralia Gray 1849

Richard E. Young and Kotaro Tsuchiya
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The genus contains the following 19 nominal species.
taxon links [up-->]Abralia trigonura [up-->]Abralia heminuchalis [up-->]Abralia multihamata [up-->]Abralia marisarabica [up-->]Abralia redfieldi [up-->]Abralia spaercki [up-->]Abralia grimpei [up-->]Abralia steindachneri [up-->]Abralia (Asteroteuthis) veranyi [up-->]Abralia similis [up-->]Abralia andamanica [up-->]Abralia omiae [up-->]Abralia astrolineata [up-->]Abralia fasciolata [up-->]Abralia siedleckyi [up-->]Abralia astrosticta [down<--]Enoploteuthidae Interpreting the tree
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Containing group: Enoploteuthidae

Introduction

Species of Abralia are small squid some of which are associated with shallow bottoms on steep slopes and as such are members of the mesopelagic-boundary fauna.

Brief diagnosis: 

An enoploteuthid ... 

Characteristics

  1. Arms
    1. Arm suckers present distally on Arms IV.

  2. Tentacles
    1. Manus of club with one series of hooks; two series of suckers.
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Oral view of the tentacular club of Abralia veranyi, female, 38 mm ML, North Atlantic. Photograph by R. Young.

  3. Buccal crown
    1. Typical chromatophores on oral surfaces of buccal crown.

  4. Photophores
    1. Enlarged photophores on tips of arms IV generally absent; if present, not covered by black chromatophores (exception in A. astrolineata).
    2. Five to twelve photophores on each eye.
    3. Complex photophores of integument without red-colored filters.
  5. Spermatangia receptacles
    1. Located under dorsal collar, in median pocket at posterior end of nuchal cartilage, or under gladius between stellate ganglia.

Comments

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window

Figure. Ventral view of arm IV integumental photophores of A. trigonura, off Hawaii. Photograph by R. Young.

In life, the integumental photophores have a characteristic appearance. The photo shows the three types of integumental photophores. A "lensed" photophore (white arrow) has a blue color and white ring. A "simple" photophore (black arraow) is small and violet-colored. The remaining are "complex" photophores and have a central green color and small "satellite" green-color points. Often complex photophores will appear blue rather than green depending on their physiological state (see Young and Arnold, 1982). The black dots are chromatophores.

The structure of a complex photophore can be seen here. 

Classification

Species of Abralia are generally placed into six subgenera but these may not all be natural groups. The following table (modified from Tsuchiya and Okutani, 1988, and Tsuchiya, 1991) shows the primary taxonomic features of each group.

  Abralia
(Abralia)
Abralia
(Asteroteuthis)
Abalia
(Astrabralia)
Abralia
(Pygmabralia)
Abralia
(Heterabralia)
Abralia
(Enigmoteuthis)
No. sucker series at distal end of sucker series on arms I-III
3-4
3-4
2
2
2
2
Which arm IV hectocotylized
Right
Left
Right
Right
Left
Right
No. Club hooks
5-7
3-5
<5
1-3
2-3
>5
No. of types of ocular photophores*
2
2
1
1
2
1
Large, unpigmented caudal and arm IV-tip photophores
No
No
Yes
No
No
No
Attachment of buccal connective to arm III
Ventral
Ventral 
Ventral 
Ventral 
Ventral 
Dorsal
*Refers to reflective properties (e.g., orange, silvery, opaque) that indicate structural differences other than size.

References

Nesis, K. N. 1982. Abridged key to the cephalopod mollusks of the world's ocean. 385,ii pp. Light and Food Industry Publishing House, Moscow. (In Russian.). Translated into English by B. S. Levitov, ed. by L. A. Burgess (1987), Cephalopods of the world. T. F. H. Publications, Neptune City, NJ, 351pp.

Tsuchiya, K. 1991. Abralia fasciolata, a new species of enoploteuthid squid from the western Indian Ocean (Cephalopoda: Oegopsida). Bulletin of the National Science Museum, (series A) 17(2):69-79, 16 figures.

Tsuchiya, K. and T. Okutani. 1988. Subgenera of Enoploteuthis, Abralia and Abraliopsis of the squid family Enoploteuthidae (Cephalopoda, Oegopsida). Bulletin of the National Science Museum, Tokyo (series A) 14: 119-136.

Young, R. E. and J. M. Arnold. 1982. The functional morphology of a ventral photophore from the mesopelagic squid, Abralia trigonura. Malacologia 23: 135-183.

Young, R. E., L. A. Burgess, C. F. E. Roper, M. J. Sweeney and S. J. Stephen. 1998. Classification of the Enoploteuthidae, Pyroteuthidae and Ancistrocheiridae. Smithsonian Contr. to Zoology, No. 586.

Title Illustrations
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Click on an image to view larger version & data in a new window
Scientific Name Abralia trigonura
Location Off Kona coast of Hawaii Island. This is the same locality and species, but different date, as the squid in the title photograph of the Enoploteuthidae page.
Specimen Condition Live Specimen
Identified By J. Milisen, R. E. Young
Behavior Squid swimming close to ocean floor at night at a depth of about 25 m, attracted by photographer's lights.
Sex Male
Life Cycle Stage Mature
Size 35 mm ML (guess)
Copyright © 2018 Jeffrey Milisen
About This Page


University of Hawaii, Honolulu, HI, USA


Tokyo University of Fisheries, Tokyo, Japan

Page: Tree of Life Abralia Gray 1849. Authored by Richard E. Young and Kotaro Tsuchiya. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Young, Richard E. and Kotaro Tsuchiya. 2018. Abralia Gray 1849. Version 29 March 2018 (under construction). http://tolweb.org/Abralia/19642/2018.03.29 in The Tree of Life Web Project, http://tolweb.org/

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