Tremoctopus at Molassas reef in FL

Streetjudge, it is the same genus, no doubt, (sub)species is a different question. There are currently at least three species "accepted" by mainstay cephalopod science, the gelatinous blanket octopus, Tremoctopus gelatus, Tremoctopus robsoni and the palmate octopus, Tremoctopus violaceus gracilis and its sister subspecies the common blanket octopus, Tremoctopus violaceus violaceus. "Your" Tremoctopus and the Del Ray specimen are anatomically very much the same, but only appear different in coloration, the latter showing the distinct dark purple hue dorsally and the silver to orange, ventrally, that seems to typify T. violaceus violaceus. The mottled, or "spotty" appearance of your specimen is a pattern I would normally associate with T. violaceus gracilis, but you'd need proper DNA sequencing done to corroborate the evidence. Again, understanding Octopus species on visuals alone is very hard, as they have the ability to change their color, skin texture and even body shape to a certain extent, making a positive ID from a static photograph alone quite close to impossible.

@skywindsurfer, the sexual dimorphism between male and female Tremoctopus is likely the largest of all cephalopods, much as with the closely related Argonauta.

@chrono_war01, the Portuguese Manowar's tentacles are usually between 10 and 15 meters long, and the nematocysts will fire off a venom when in contact that causes (sometimes) severe pain for up to two hours or so, but is hardly ever lethal, bar the occasional rare reported event (in which case anaphylactic shock might be the culprit, perhaps?).

Additional trivia: juvenile female and male Tremoctopus actually "harvest" Physalia nematocysts to tote as weapons of self defense on their dorsal arm pairs.
 
Will look up. Interestingly enough T. v. gracilis should be confined to the indo-pacific, whereas I am fairly positive it has been sighted near Malta at least on one occasion. I am always weary about "certainties" in pelagic species, certainly regarding geographic spread.
 
skywindsurfer;172158 said:
Aside from being a pelagic animal

There is no aside... They'll likely grow to the same age as most cephalopods, the males need only invest a little growth to attain their 2,5 cm TL, so I can't imagine them living more than a year, females likely similar, but who knows, I personally know of no reliable studies, hitherto.
 
OB;172161 said:
No luck so far in my preliminary search, but one would assume pelagic crustaceans?

Or fish. I swear I heard/read somewhere about them using man o war not for defense, but for catching food. Hmmm.
 
man -o war eat fish. they use there tentacles to stun them. it is impressive to the see how large a fish they can take down. I have seen a relatively small man-o-war caring a 8" fish. The local news reports only a one or two human deaths a year but they are usually related to an allergic reaction, or heart condition.
 
Thales;172163 said:
Or fish. I swear I heard/read somewhere about them using man o war not for defense, but for catching food. Hmmm.

It's a relatively old paper, but here is:

Tremoctopus violaceus Uses Physalia Tentacles as Weapons, Everet C. Jones

Science 22 February 1963: Vol. 139 no. 3556 pp. 764-766

DOI: 10.1126/science.139.3556.764

ABSTRACT

Immature octopods (Tremoctopus violaceus) have been found with numerous fragments of tentacles of the coelenterate Physalia attached to the suckers of their dorsal arms. The probable method of acquisition, the evidence of adaptation for holding the tentacles, and the possibility that the octopod uses these coelenterate tentacles as offensive and defensive weapons are discussed.
 
It would make sense that a palegic octopus like the blanket octopus would use them as a means of collecting food. With their enlarged/elongated webbing creating a floating shade, I do not see why fish would not be drawn to the floating octopus for protection against larger predatory fish unaware that their 'shelter' is really a predator waiting for them. The octopus then merely has to sting and grab the prey.
 
OB;172165 said:
It's a relatively old paper, but here is:

Tremoctopus violaceus Uses Physalia Tentacles as Weapons, Everet C. Jones

Science 22 February 1963: Vol. 139 no. 3556 pp. 764-766

DOI: 10.1126/science.139.3556.764

ABSTRACT

Immature octopods (Tremoctopus violaceus) have been found with numerous fragments of tentacles of the coelenterate Physalia attached to the suckers of their dorsal arms. The probable method of acquisition, the evidence of adaptation for holding the tentacles, and the possibility that the octopod uses these coelenterate tentacles as offensive and defensive weapons are discussed.

Thanks! I'll try to remember to dig it up this week.
 
Regarding food items.... Come to think of it, Argonauta feeds on pelagic molluscs, mainly, so I would not be at all surprised if the same were true for Tremoctopus, seeing how closely related it is in morphology, physiology and planktonic lifestyle. Its interaction with Physalia has a slight parallel with Argonauta's usage of certain species of jellyfish as additional feeding apparatus.
 
OB, somewhere there is a nice write up about Argonauta using a jelly to sheild itself from a diver trying to photograph it so there may be a similarity there as well. I believe the photographer was mark Strickland (as referenced in Wikipedia) but I can't seem to find the article. Ah, now I know where it was. It was in the issue of the now defunct ReefLife magazine that was primarily about cephalopods. Fortunately, I have a hard copy :biggrin2: (many thanks again Sedna).
 

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