awaiting a Marginatus to arrive on Wednesday

so we know its not a marginatus-- but what type of octopus has two white spots (eyes) on the mantle--an aculeatus
My other aculeatus doesn't have these spots, but has the long white and dark mohawk streak--
 

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The stripes on the third one (bottom) are not an ID but a pattern often present in the male of the species at mating. I half suspect the original photographer is about and would ID it as aculeatus, not mototi.
 
DWhatley;182625 said:
The stripes on the third one (bottom) are not an ID but a pattern often present in the male of the species at mating. I half suspect the original photographer is about and would ID it as aculeatus, not mototi.

I would agree with that assessment. :biggrin2:
 
so what do you think of the white false eyes spots on the mantle--does this confirm aculeatus

this is the octopus that was supposed to be a coconut
 

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AS far as I know official ocelli are all found no the webbing below the eyes. The white marks are either a pattern or something I have noted on photos of most species (farther forward than on many I have seen but similar). I suspect they mark something common and biological but I have never had an answer to my query as to what they might be.
 
Fun thread! Sorry for the delay in checking in- I just got back from a climbing trip in Joshua Tree where I kept the internet to a minimum.

The pic you posted looks like A. aculeatus. The dark spots on the mantle are "lateral neck dark spots." When the octopus is sitting at its den they can send the same "false eyespot" signal, but they are not what we normally call an ocellus (typically about halfway between the eyes and the edge of the webs on each side).

Just in case you're interested:

Top pic is indeed A. marginatus. There are two color morphs described (and possibly more out there). One has distinct bright white sides of the suckers, and the funnel might not be very yellow. A. marginatus can have a transient blotch on the side that looks ocellus-like, but it's not well defined (more like a uniform purplish thumbprint), and it isn't visible all the time. The purple margins are sometimes not prominent as well. A. marginatus has fairly bumpy-looking skin, the tops of the bumps are pale or light purple, and the grooves in between are purple- this is because the skin is stretched over the bumps and chromatophore density lower (and higher in the grooves). Sometimes there is a dark purple triangle on each side of the eye (if I have time I'll post pics in the next few days). The lines on the arms are dark purple- when they show them- and run only from the base of the arm to the tips, right along the top edge of the suckers. If you have access to an academic library, look at the pics in "Field observations of mating in Octopus tetricus Gould, 1852 and Amphioctopus marginatus (Taki, 1964)(Cephalopoda: Octopodidae)". If not then PM me and I'll send you the pdf. Perhaps most notable about A. marginatus and other members of the genus is the distinctly short front arms (Arms I) and the very shallow front web (web A- the webbing between the two front arms). This group also has much shorter, thicker arms (usually appearing about 1.5-3 times as long as the mantle length, depending on the position) relative to the larger mantle as compared to A. aculeatus.


The pic on the right looks like a young mimic or relative.

And nice A. aculeatus shot of the male stripes! Note the long arms- many times longer than the mantle is long.



Hope this helps!
 
I just got back from a climbing trip in Joshua Tree
Does that mean you were looking for the Northwest Tree Octopus in AZ? :wink:

I copied your marginatus description to a new thread in the Cephalopod by species thread to be able to reference it more easily in the future. If you get to your photo album, could you post the pictures to that thread and add a link here? I wish we would see these if they will survive shipping but with the observations Thales has made about their low stress levels, perhaps it is best we don't.

Muctopus, do you know what the two paralell white spots are? I have asked the question a dozen times without any takers for an answer. I know most, if not all, octopuses show them in the same place (I missed getting the camera when I saw them on Little Bit two days ago after this discussion). I am assuming there is some biological element related to them and can find them in most photos in Noman (in addition to having seen them on at least two species I have kept (they would be hard to detect on O.briareus).
 
Ahh the 'Dorsal Mantle White Spots'...Lots of octopuses have them. They're leucophore-rich fields on the skin that to not move. Various authors (I think Packard, Sanders, Hochberg, and Hanlon) have mentioned the DMWS and/or frontal white spots on the arm crown may distract a predator, though they do draw attention to an important part of the body (the bit holding all the guts). It's possible these fields also display polarized signals that we can't see. I posted the aculeatus ethogram, and this illustrates a lot of body pattern components, even if their function isn't given.

Thanks for adding the marginatus info. I'll try to get to the pics soon, and will cross ref to your post.
 

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