Note

Abraliopsis pacificus: Integmental photophore patterns

Richard E. Young
Drawings below are first made from photographs that are then compared with the preserved squid under a microscope. A small error will occur in identifying the two classes of photophores (red - counterilluminating photophores with red color filters = "complex photophores, and blue - simple photophores plus lens bearing photophores = "non-complex photophores." Blue photophores cannot, yet, be reliably separated, in preserved squid, into the two component types.). A damaged or developing/transforming cannot always be reliably identified. Even the presence or absence of photophores can be difficult on strongly curved surfaces, for example, the sides of the head or mantle when viewed ventrally. Therefore, the photophore arrangement, seen below, is most accurate on the ventral surfaces when viewed ventrally and on the lateral surfaces when viewed laterally.
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Figure. Ventral views of the integumental photophores of Abraliopsis pacificus, female, 28 mm ML, western North Pacific. Left - Photograph of the preserved squid. Middle - Outline drawing from photograph with all integumental photophores represented by cyan-colored dots. Right - The squid photograph with superimposed dots on integumental photophores. Red dots - Complex photophores. Blue dots - Non-complex photophores. Images by R. Young.

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Figure. Same squid, same view as above. Left - Drawing showing only the non-complex (blue) photophores. Left middle - Drawing showing only the complex (red) photophores. Right middle - Same as previous drawing with lines connecting red photophores to aid comparisons of photophore patterns between species. Right - Drawing showing all photophores and lines showing red photophore patterns. Images by R. Young.

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Figure. Side view of the head and proximal regions of the arms of the same squid (25 mm ML) as above.Left - Photograph of the preserved squid. Middle - Outline drawing from photograph with all integumental photophores represented by colored dots. Right - Outline drawing over dimmed photograph with all integumental photophores represented by colored dots, and with lines connecting some photophores. Red dots - Complex photophores. Blue dots - Non-complex photophores.  Lines connecting photophores assist in understanding the organization of the photophores. Black lines - Patterns based on red photophores. Yellow line - Pattern based on red and blue photophores. Images by R. Young.

*** Abraliopsis pacificus: White photophores of the funnel groove ***
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Figure. Ventral view of the funnel-groove region of A. pacificus, female.  Top - Funnel groove showing photophores of funnel groove and surrounding tissue. Middle - In the photograph, white dots are placed over the "white" photophores of the funnel groove. Black dots are placed over the two most posteromedial "red" photophores of the ventral head to mark the anterolateral edges of the funnel groove. Bottom - Same pattern of dots as in photographs but dots are colored. Colored dots, lines - Aid in comparison of patterns between species. Open dots - Represent photophores that are either of uncertain status as "white" photophores or have variable presence.  Images by R. Young. Comparison of white photophore patterns for all Abraliopsis species can be found here.

Comments: Summary of photophore distributions. (photophore definitions found here)

ARMS:
Medial arm IV Series - Continuous; reaches 80% of arm length.
Central Arm IV Sector - Few, scattered blue photophores near arm base.
Lateral arm IV Series - Continuous; reaches arm tip.
Lateral Membrane Series of arm IV - Continuous; reaches at least to 50% of arm length. *Needs confirmation.
Arm III Series - Continuous; nearly reaches arm tip.

HEAD - Typical scattered pattern with:
Median Head Series - Absent.
Median Head Sector - Scattered photophores. At 28 mm ML, about 7 red photophores.
Medial Head Series - Arbitrary designation: About 6-7 red photophores (28 mm ML).
Lateral Head Sector - Scattered photophores. At 28 mm ML, number of red photophores about same (ie, 5-7) as in median head sector.
Lateral Head Series - Fairly well defined.
Window Sector - Few scattered blues at either end. Otherwise without photophores.
First Lateral Window Series - 2 posterior segments containing 2 red photophores each; one anterior segment containing 6 red photophores at 28 mm ML.
Second Lateral Window Series  - Present, with 4 red photophores.
Eyelid Series - Red photophores only on ventral half of eyelid. Posterior Eyelid Series with one large blue photophores displaced slightly posteriorly from eyelid series. Formula: RbBB.
Occipital Series - RbRbR at 28 mm ML.
Lateral Funnel-groove Series - 4 (2+2) red photophores; not well aligned.
Olfactory Photophore - Red at 28 mm ML.
White Patch (funnel groove).. ModeratePattern (red, green, blue + (possibly) yellow with size).

FUNNEL: Patches not well demarcated
Medial Patch - Scattered red photophores.  
Lateral Patch - Two red photophores.

MANTLE - Typical scattered pattern with:
Median Mantle Sector - Blue photophores obscure central bare strip in anterior third of mantle. Distinct but narrow bare sector in posterior 2/3 of mantle.
Medial Mantle Series - Irregular.
Mediolateral Mantle Sector - With scattered red and blue photophores.
Lateral Mantle Series -  Not apparent.
Mantle-angle Series - Barely recognizable.


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 pacificus: Integmental photophore patterns 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.

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