Wunderpus photogenicus!
I can’t believe that is a real species name.
I’ll be up for hearing others that make you crack a smile.
(crossposted from A Developing Passion)
Copyright patcsy888
Apparently one can track an individual octopus of this species by simply recording its unique pattern of white spots on its back on camera, and these don’t change over time. Much like for whales and their battle scars.
Each animal bore a circular pattern of approximately six white spots in the center of the mantle. However fusions of these spots and the location of additional small markings in this region differed among individuals. Lateral markings also appeared to vary asymmetrically.
My attention was drawn to this article because I’ve been cogitating my next pigment-related post. I’m actually not intellectually that interested in pigment cell or skin biology, but I have a vested personal interest (the Naevus 2000 association general assembly is next weekend) and in vertebrates at least, pigment cells do come from my favorite developmental cell type, the neural crest cell.
However, the octopus is not a vertebrate, as cuddly and smart as it is.
Even I can’t get access to this article but the abstract is fairly informative: the octopus has organs called “chromatophores” which contain different kinds of pigment, and are under neuromuscular control. This enables them to change patterns and camouflage with their environment. They overlie “iridophores” which provide a kind of iridescent, mirror-like light-reflecting surface over which the different colors are deployed like filters.
I don’t know if the white markings of Wunderpus photogenicus are simply the lack of colored pigment in those areas, or a concentration of a special sort of iridophore, or both. I would speculate it is the same sort of thing that keeps their sex organs white – as mentioned by the latter authors, collagen arrangements in the skin can have a high refractive index (think of the tendons in a leg of chicken).
So, as a developmental biologist, looking at this animal makes me think of a few things:
- Is the genetic mechanism for alternative white and dark patches on the legs related to that which enables the periodicity of segments?
- How do they get personalized patterns on their backs? And why white? Can the chromatophores cover them up?
- Isn’t it sort of dangerous to attract predator attention to external sex organs?
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Later edit: Thanks to Bob, I was able to access the large article by J.B. Messenger entitled Cephalopod chromatophores: neurobiology and natural history.
The white pigment is from a dedicated cell type, the leucophore:
Most loliginid squids lack leucophores and complete retraction of the chromatophores produces instead the transparency that can be so important for camouflage in epipelagic animals. [Leucophores] are elongated, flattened cells, approximately 20 um long, covered with over 1000 tiny, stalked ‘knobs’, the leucosomes. They are colourless but refractile, the leucosomes scattering light to produce the chalky whites seen in incident white light. {…} It should be recalled, however, that the leucophores will faithfully reflect incident light across the entire visible spectrum and that the so-called ‘white’ areas will appear blue in blue light or red in red light. This may enable the skin to match the hue of the background as well as its brightness.
Gotta love that word, loliginid.
Christine L. Huffard, Roy L. Caldwell, Ned DeLoach, David Wayne Gentry, Paul Humann, Bill MacDonald, Bruce Moore, Richard Ross, Takako Uno, Stephen Wong (2008). Individually Unique Body Color Patterns in Octopus (Wunderpus photogenicus) Allow for Photoidentification PLoS ONE, 3 (11) DOI: 10.1371/journal.pone.0003732
Posted on Friday, November 14th, 2008 at 5:41 am Categorized as:General You can leave a response, or trackback from your own site.
November 14th, 2008 at 11:16 am
“I don’t know if the white markings of Wunderpus photogenicus are simply the lack of colored pigment in those areas, or a concentration of a special sort of iridophore, or both.”
I don’t know either, but my guess is it’s a combination of both. The expression of these white spots is somewhat behaviorally controlled. The white spots can appear dull when the animal is camouflaged. When Wunderpus is approached by a potential predator, the contrast of the pattern increases (background color becomes more uniform, and white spots become brighter). I’ll try to squeeze in time to check a specimen later today to see how dense chromatophores are over the white spots.
Also- I don’t have Messenger’s paper in front of me right now, but a couple of cephalopods have a visibly prominent ovary or testis (internal organs). In at least one octopus (Abdopus aculeatus) males prefer to mate with large, gravid females. Showing off gonad size may be some sort of sexual display.
November 15th, 2008 at 5:04 pm
Cool!! Everything sounds plausible. Thanks, Crissy! Anytime you have any musings about human or chicken embryos, please feel free to ask…
November 30th, 2008 at 7:26 pm
Mike Archer discovered a prehistoric platypus and wanted to name it “Hotcrossbunodont”. But it was frowned upon by his colleagues and it now bears the name “Kollikodon”, which means “bread roll tooth”.
Also the scientific names that make me giggle are the ones that look like very little effort has gone into the naming. Like the black rat (Rattus rattus) or the Western lowland gorilla (Gorilla gorilla gorilla)
December 1st, 2008 at 7:41 am
Kollikodon sounds like a name I’d be glad to learn, though, at least as a kid. Like Diplodocus. Hotcrossbunodont does not seem to have the same etymological purity to it…