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Abraliopsis (Abraliopsis)

Richard E. Young
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taxon links [up-->]Abraliopsis pacificus [up-->]Abraliopsis morisii [up-->]Abraliopsis sp. NC4 [up-->]Abraliopsis hoylei [up-->]Abraliopsis tui [up-->]Abraliopsis sp. Z [up-->]Abraliopsis sp. B [down<--]Abraliopsis Interpreting the tree
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Containing group: Abraliopsis


Species of Abraliopsis (Abraliopsis), with the exception of A. (Boreabraliopsis) felis, are recognized by their scattered photophore patterns of both complex and non-complex photophores. Their differences with A. felis are given on the A. (B.) felis page. Within the scattered arrangement there may be subtle patterns that are difficult to recognize which makes species identification mostly dependent on non-photophore characters.


The relationships of the species of Abraliopsis (Abraliopsis) is summarized in the following table.

  A. pacificus
A. tui
A. sp. B
A. sp. NC4
A. morisii
A. hoylei
A. sp. Z
Subtropical northwestern Pacific
Subtropical Pacific near New Zealand
Tropical central Pacific
Tropical Pacific near New Caledonia
Tropical-temperate Atlantic
Tropical Indian Ocean
Subtropical, temperate South Atlantic
Dorsal flap on hectocotylus
 ? No
Arms IV length index (=%MLx100)
x̅ = 68
x̅ = 74
x̅ = 90 ca. 70-90
75 (?)
Median Mantle Sector with bare-strip indistinct in anterior 1/5 of mantle.
1st Lateral Window  Series with gap
Yes, but minor
 ? Yes, but minor Yes, but minor No
Second lateral window series present
Yes (28 mm ML)  ? No (26 mm ML) No (26 mm ML) Yes (25 mm ML) ? Yes, but large gap. (29 mm ML)
Lateral Funnel-Groove series
2+2, non-overlaping (28 mm ML) 
 ? 2+2, non-overlaping (26 mm ML) 
2+2, non-overlaping (26 mm ML)
4+2, overlapping (at 35 mm)
3+3, non-overlapping (29 & 35 mm ML)
Olfactory Photophore/Series
Red/Absent (28 mm ML) ?
Blue/Absent  (26 mm ML) Red/Absent (26 mm ML) Blue/absent (35 mm ML) ?
Red/present (29 mm ML)
 Head width index (=%MLx100) Males: x̅ = 35
x̅ = 33
Males: x̅ = 45
Females: x̅ = 41
 ?  Females: x̅ = 40
x̅ = 39 combined sexes
Distinct posterior crescent ridge connects occipital folds 3 and 4
 No Yes
 Yes Yes
Fin width index (=%MLx100) x̅ = 92
x̅ = 106
x̅ = 100 ?
No. arm IV hooks
x̅ = 21 
x̅ =12.5 (11-14)
x̅ = 18.8 (16-21)
19-21 (?) 18; 20 (hecto)
Length: sperm mass/spermatophore
Lateral head sector, red photophores *
 5-7 (28 mm ML) ?
6 (26 mm ML) 0-1 (26 mm ML) 9-11 (25 mm ML) ?
 Not Applicable

x̅ = "x-bar" = mean

* - Difficult character to use as Sectors are somewhat arbitrary and number of red photophores is dependent on size as well as species.


This table indicates that the presence or absence of a dorsal flap on the hectocotylus is a critical character in identifying species. Unfortunately it can be a difficult character to recognize if squid are not in very good condition. The two species (A. tui and A. sp. B) that lack a dorsal flap are easily separated by the several characters of which (1) the number of hooks on arms IV and (2) the median strip bare of photophores in the anterior 1/5 of the mantle (most/all species have a bare strip in the posterior 2/3 of the mantle). A. sp. B is also distinctive in having a very broad head which is easily recognized (see the top title photograph on this page).

Among the 4 species that have a dorsal flap on the hectocotylus, A. sp. Z is easily recognized by (1) the greater abundance and distinctive arrangement of head photophores and (2) the median strip bare of photophores in the anterior 1/5 of the mantle. The remaining three are more difficult. A. sp. NC4 is separated from A. pacificus and A. morisii by the number of red photophores present in the lateral head sector. The latter two species can be separated by (1) the color of the olfactory photophore at least between 28 and 35 mm ML and (2) their habitat. A. hoylei cannot be identified at present; its identity must wait until we know what species of Abraliopsis occur at its type locality.

Unlike members of subgenera Pfefferiteuthis and Micrabralia the club membranes and hook-sizes appear to be similar in all members of the subgenus Abraliopsis


Title Illustrations
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Scientific Name Abraliopsis sp. B
Location Hawaiian waters
Specimen Condition Dead Specimen
Sex Male
Life Cycle Stage Mature
View Ventral
Size 20 mm ML
Image Use creative commons This media file is licensed under the Creative Commons Attribution License - Version 3.0.
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Scientific Name Abraliopsis morisii
Location North Atlantic, 43N, 28W
Comments Photographed aboard the R/V G.O. SARS, during the MAR-ECO expedition 2004
Specimen Condition Fresh
Body Part Photophore arrangement on head and mantle
View Ventral
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright ©
About This Page

University of Hawaii, Honolulu, HI, USA

Correspondence regarding this page should be directed to Richard E. Young at

Page: Tree of Life Abraliopsis (Abraliopsis). Authored by Richard E. Young. 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. 2013. Abraliopsis (Abraliopsis). Version 03 November 2013 (under construction). http://tolweb.org/Abraliopsis_%28Abraliopsis%29/149532/2013.11.03 in The Tree of Life Web Project, http://tolweb.org/

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