Architeuthis: How many hectos?

[Rick E]

In researching the anatomy of the giant squid, I have found a discrepancy re- the number of hectocotyli in this species. According to Roper and Boss ("The Giant Squid", Sci. Amer. 264(4):96-105) the kraken has 2 hectocotylized arms. O'Shea's "Architeuthis Reproduction" article states that males have no hectocotyli. Can someone clarify this for me? Thank you.

[L8 2 RISE]

I have no Idea what most of that means :bonk: but... :welcome: to the site, Im sure most of your questions will be able to be answered by the experts on this site...so Ill leave it to them

:welcome: again

[Spence24]

Well...I THINK and that's not saying much, that it does in fact have too. That being said I will let someone else clarify this for you. And :welcome: to the site.

[monty]

For what it may be worth, Nesis also reports "Both ventral arms are hectocotylized." I'm going to guess that this is more of an interpretation question than a factual one, since Steve has certainly examined enough of these beasties to know what the ventral arms in males look like, so I'm going to bet my :twocents: that there is sexual dimorphism in the 2 ventral arms, but Steve doesn't believe either is used as a hectocotylus (to transfer sperm) because he's of the opinion that spermatophores are injected into the female's flesh directly by the penis. Note that that's just a guess, though, hopefully :oshea: will clear this up shortly... I'm going to edit the subject a bit in the hope of getting his attention faster, too :grin:

Oh, yeah, and :welcome: to TONMO!

[Graeme]

Hey hey. Wlecome to TONMO! :grin:

I am unsure about the frequency of squid with hectocotylii, but I do know that those that do possess a penis do indeed show sexual dmimrorphism. The scaled squid Lepidoteuthis grimaldii shows such a curious difference. Males have hooks on two arms. It is still unknown as to their actual function, whether it's for holding a female during copulation, but I always wondered if it was to show the male's fitness during courtship. larger hooks dictate a better specimen. This is only speculation though, and off on a bit of a tangent:lol: Steve's the man to ask.

[Tintenfisch]

I believe that, in general, squid species in which the male has a 'terminal organ' ( = dedicated sperm transfer organ or 'penis' within or protruding from the mantle cavity) are not hectocotylized. BUT I think Dr. Kubodera said something about hectocotylization in Architeuthis, I just (helpfully) can't remember what it was. So I'll point :oshea: in this direction...

[Rick E]

Thanx for the welcome!

I'm new to blogging, so I'm still trying to figure it all out. Kinda weird, but it has a lot of potential.

Can you tell me how I was dubbed "larval mass"?

[Rick E]

Thanks for the Welcome!

Most references i've found also indicate two hectos. It's kinda puzzling, with all the carcass strandings and sperm whale eviscerations over the centuries, that there is not quick and easy answer to this question. I'll be interested in hearing what other respondents have to say.

Thanx for responding. By the way, do you know what the significance of my assigned moniker "larval mass" is?

[Architeuthoceras]

Thanx for the welcome!

I'm new to blogging, so I'm still trying to figure it all out. Kinda weird, but it has a lot of potential.

Can you tell me how I was dubbed "larval mass"?

:welcome: Rick, I dont know nothin bout no hecto but...

0 posts on the forum you are a Lurker, 1-6 = Larval Mass, 7... Pygmy Octopus on up to Titanites for over 5000 posts

[Rick E]

Thanx for the welcome!

Your response is much appreciated, and makes a lot of sense. Hopefully, Dr. O'Shea will be able to clarify the situation.

[Rick E]

Thanks for your detailed response, and your welcome. I'm new to this blogging thng; it's turning into quite an adventure!

[Rick E]

Thanks for replying. The answer to my question seems to be getting more complicated by the minute. I'm getting more and more curious as to What Dr. O'Shea's response will be.

[Rick E]

Definitely weird.....Thanks

[Architeuthoceras]

If you thinks it is weird now, wait till you get to be a giant gelatinous blob :roflmao:

[Spence24]

If you thinks it is weird now, wait till you get to be a giant gelatinous blob :roflmao:

Haha...Curious about what that status was, I looked it up last night and was pleasantly suprised...:roflmao:

[Steve O'Shea]

I've been away for a few days, sorry.

I'd maintain absolutely no trace of hectocotylisation on any arm (I've not seen anything remotely 'hectocotylised' at any rate - certainly not comparable to that on other taxa for which the hectocotylus is very pronounced).

You'd have to be very careful when referring features found on both ventral arms to hectocotylisation.

[monty]

I've been away for a few days, sorry.

I'd maintain absolutely no trace of hectocotylisation on any arm (I've not seen anything remotely 'hectocotylised' at any rate - certainly not comparable to that on other taxa for which the hectocotylus is very pronounced).

You'd have to be very careful when referring features found on both ventral arms to hectocotylisation.

Does the sketch (figs G and G1) on p. 219 of Nesis not match your observations, then, or do you just consider that quirky arm anatomy (presumably sexually dimorphic as described)? It certainly looks, er, "groovy" in a classic hectocotylus style...

5851

I note that the Roper & Sweeeney FAO guide also says "arms IV hectocotylized" but don't have a picture. I can't think of another ceph species that has 2 arms modified as hectocotyli, although there are plenty of non-hectocotylus sexual dimorphisms that show up on symmetric arm pairs, like enlarged suckers on GPOs and mercatoris... further googling suggests that there are a lot of species that match a search for "both arms hectocotylized" so I guess I'm just ignorant. But there seems to be some ambiguity when anatomists use the term whether the terms mean "sexually dimorphic characters of arms" or "arm is actually used to transfer spermatophores."

[DWhatley]

Monty,
My mercs have enlarged suckers on all eight arms and Sisturus has double enlargements (side by side) on all arms. Mucktopus' paper and a later Q&A described only 2 or 4 arms with the enlargements as typical on the various dwarf species. She also mentioned that the use is still unconfirmed.

[monty]

Monty,
My mercs have enlarged suckers on all eight arms and Sisturus has double enlargements (side by side) on all arms. Mucktopus' paper and a later Q&A described only 2 or 4 arms with the enlargements as typical on the various dwarf species. She also mentioned that the use is still unconfirmed.

Right, I meant that in most species, the sexually differentiated traits appear symmetrically on 2, 4, 6, or 8 arms, in pairs on opposite sides. The hectocotylus is a major exception to this, in that it's usually only a modification of one arm, and the one opposite it in the pair doesn't show the difference.

Do any of your mercs show modified suckers differently on the left and right sides of a single arm pair?

[DWhatley]

I guess humans are somewhat deviated this way too :sly:

[monty]

I guess humans are somewhat deviated this way too :sly:


"'Cause that's the hand I use... well, never mind." -- Simon & Garfunkel

[DWhatley]

Saw them in concert once :sagrin:

I tried to look at Sisturus' arms as matching or unmatching pairs but I think photos would be the only way to see if there is a pairing commonality as he really doesn't stay very still if I am sitting at the tank and his arms are not stretched out if he is just chilling on the glass. I am going to be devistated when this one goes. He is so much more like a bigger octo than most pygmies. If he dies the way Trapper did, I really won't be able to tell a lot about the suckers then either as her arms shrunk and weakened as she aged. So much so that I initially thought the suckers at the ends of her arms had been scraped or eaten off.

[Rick E]

Thank you. That answers my question.

[Rick E]

I figured my question would have a simple, black-and-white kind of answer; I didn't anticipate so many shades of grey.

[Steve O'Shea]

Does the sketch (figs G and G1) on p. 219 of Nesis not match your observations, then, or do you just consider that quirky arm anatomy (presumably sexually dimorphic as described)? It certainly looks, er, "groovy" in a classic hectocotylus style...

Thanks Adam. I've seen a few things like the illustrations in Nesis, but it's really hard to know whether these arms are damaged or not, as so often in trawl-caught specimens (the ones we deal with most often) the arm tips are incomplete.

I have had quite a number of mature males with one or two ventral arm tips complete, and have seen this condition in one or two specimens only (not in the majority), and never on both arms; I have also seen this condition on some other arms (not the ventral pair). I assumed it to be regeneration rather than hectocotylisation. I do not believe that absence of this 'condition' in some individuals (mature) means that there is more than one species (I believe there is one species only).

As Kat said earlier, those species that lack hectocotylisation 'as a rule' implant spermatophores in/on the female using their large 'terminal organ' (being a 'family show'), and given the 'enormous' size/length of this organ in Architeuthis I would be rather surprised to see any trace of modification of the ventral arms to assist in spermatophore transfer. The arms may be modified, but not necessarily for reproductive purposes, so we cannot assume any such modification represents hectocotylisation.

In response to some other query (sorry, I forgot who mentioned it), hectocotylisation of both ventral arms is very pronounced in some ommastrephids also (such as Nototodarus).