Sexing an Octopus - Photos of Hectocotylized Arm

Cephalover

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The wild-caught O. dofleini at the Buffalo-Niagara aquarium is missing almost all of its third arm, and I was disappointed when I found this out because now I can't tell what sex it is! Are there any other non-invasive ways to tell what sex it is?
 

DWhatley

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Some species have enlarged suckers on two or four (one of my merc had them on all eight) arms. The literature I have read and the comments by our ceph experts conclude that they don't know why this is, it is not always consistent and not all species have this differentiation. Try a scan for "enlarged suckers dofleini" (and/or GPO, or giant pacific octopus, often either the scientific or the common name is omitted) to see if the GPO falls into that category and it may say which arms to check. So far, I have not come across anything to help ID females but please post should your reseach give a suggestion. In a few species there is a distinct size difference but I don't believe the GPO is in this group (most of the one we commonly see are not).

Unless there has been recent progress that has missed our news posting, all dofleini are wc. They are a small egg species and almost impossible to tank raise (I have seen mention of trying to raise them but no indication of success. I do not have access to current studies so if it does not make the OctoBot news or the attention of one of our members there may be positive results posted that we have not yet seen).

2011-10-4 update - Attempt to raise GPO hatchlings discovered by Octobot
 

Neogonodactylus

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I recently took a series of photos of Wunderpus hectocotylus structure including close-up shots of mating and insertion. I my humble opinion they are some of the best photos of octopus mating I have ever taken. Unfortunately, I can't post them until they are published. For now, this photo of H. lunulata mating will have to do. You can clearly see the hectocotylus and spermatophoral groove. Just after this shot, I got another of a spermatophore passing down the groove. Roy
 

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DWhatley

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Roy,

It is hard to imagine the photos are better than this one!

PLEASE try to remember to put the photos here if once and IF they can be released. It is so hard to get descriptive photos! I had the most wonderful opportunity with the mercs and plenty of time to capture the "shoulder" that formed during transfer and my camera just could not focus. If you know what to look for, it is there but the clarity is so bad I have not posted it here. This is the first shot I remember even you posting showing how the arm swells during transfer.
 

Neogonodactylus

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There is a lot going on during spermatophore transfer. Can't remember if I posted this shot of A. aculeatus mating. The male is out of frame in the lower right, but you can see his hectocotylus inserted into the females mantle cavity. I fired off several shots in a couple of seconds. This is the only one with the pink patch passing down the groove. I suspect this is produced as the metachronal wave moves down the hectocotylus. Roy
 

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CaptFish

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Perfect! Now I see. I was having a hard time seeing the groove but I see it in that picture and now in the H.lunulata one too. You Rock!
 

Cephalover

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I was there today, and noticed that arm 2 appears to have a group of slightly enlarged suckers, and then a 5-cm-ish long portion with no suckers on it distal to that, and then the tip of the arm looks normal. I don't know what this means, though, as I can't find a mention of it in species descriptions of O. dofleini .

Good to see another Buffalonian! It's a small world, I guess.
 

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