Architeuthis: How many hectos?

Rick E

Pygmy Octopus
Registered
#1
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

Haliphron Atlanticus
Registered
#2
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
 

monty

Colossal Squid
Staff member
Supporter
#4
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

Vampyroteuthis
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#5
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

Architeuthis
Staff member
Moderator
#6
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

Pygmy Octopus
Registered
#7
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

Pygmy Octopus
Registered
#8
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

Architeuthis
Staff member
Moderator
#9
Rick E;107300 said:
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

Pygmy Octopus
Registered
#12
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.
 

Steve O'Shea

Colossal Squid
Supporter
#16
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

Colossal Squid
Staff member
Supporter
#17
Steve O'Shea;107328 said:
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...



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."
 

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DWhatley

Cthulhu
Staff member
Moderator
#18
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

Colossal Squid
Staff member
Supporter
#19
dwhatley;107339 said:
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?
 

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