Octo-hair or Egg Teeth?

[Fujisawas Sake]

Okay, as my first "official" Special Contributor thread post (therefore showing that I am trying to earn my keep)...

A friend of mine has some unfinished histological work done on O. vulgaris and he told me that the hatchlings have "spines" of sorts that help free them from their egg cases. These "spines" (setae?) soon vanish leaving the smooth skinned octos we all know and love.

Has anyone ever seen this? If you have, of what are these spines composed, and from what embryonic germ layer are they derived? Being analogous to the vertebrate "egg-teeth", are these found in squid? AND, if they are, could the scales mentioned on Lepidoteuthis be a neotenic derivation of these spines? Could these scales and spines be evolutionary homologues?

Any papers on this subject would be cool, if you know where I can look them up.

& ,

John

"Keep on Rockin' in the Free World"

 

[Jean]

Haven't seen them.........which really doesn't mean much! But I have seen LOTS of newly hatched octopus and sepioloidea. I've also dissected near to hatching sepioloidea out of the egg. And I've never seen anything like that. It could have been that the mag wasn't high enough tho' . I wonder how fast such a thing would be dropped or resorbed????

Steve & co....your thoughts?????

J

 

[Fujisawas Sake]

Well, the person who told me this took skin cross sections and made slides. I'll see if he can find them for scanning. He says that these structures are so far only found on some octopuses such as O. vulgaris and E. dolfleini.

I put forth the idea that maybe these are throwback structures from a trochophore-like stage of embryological development. According to my friend, these are functional and at least one paper has been written about them. I wish I knew the title.

Yeesh... Maybe I should have posted something else?

John

 

[Jean]

Well, the person who told me this took skin cross sections and made slides. I'll see if he can find them for scanning. He says that these structures are so far only found on some octopuses such as O. vulgaris and E. dolfleini.

I put forth the idea that maybe these are throwback structures from a trochophore-like stage of embryological development. According to my friend, these are functional and at least one paper has been written about them. I wish I knew the title.

Yeesh... Maybe I should have posted something else?

John

Why 'tis interesting!!! Next time I have some bubs I must have a close look!

J

 

[Steve O'Shea]

They're called 'Kolliker bristles', first reported by Kolliker (1844) for Argonauta argo. I've seen them on paralarval NZ octopus too.

Chun (1909; 1975 translation) reports [paraphrased] 'present in Octopus vulgaris, and embryonic Argonauta argo, where they are especially numerous in the vicinity of the eyes (of Argonauta). Further, these hairs are characteristic of embryos and early paralarvae, but later disappear'.

Hope that helps; there are some sensational picks in Chun's work (plates). The trochopore reference is probably a bit of a stretch; it doesn't surprise me that the paralarval forms have additional sensory structures - being pelagic they probably need to know exactly what is happening around them (predator, prey or current detection). I don't know of the paper you refer to (your cobber) - I know I have something here somewhere, buried in boxes of crap ... but finding anything right now is an impossibility.

O

 

[Steve O'Shea]

I should add, the 'egg tooth' reference in the title was rather good; yes, these too have been referred to - I think by Boletzky (a spine at the posterior of squid to assist in breaking free of the egg capsule). Please prompt me later - I can find this somewhere ...

 

[Fujisawas Sake]

BADASS!! THANK YOU STEVE!!

*ahem* Thanks for the info... I'll start looking it up immediately!

John

 

[Jean]

I should add, the 'egg tooth' reference in the title was rather good; yes, these too have been referred to - I think by Boletzky (a spine at the posterior of squid to assist in breaking free of the egg capsule). Please prompt me later - I can find this somewhere ...

Actually now I think of it, when I've been watching S. pacifica hatch, they hve a pointed end, I just never stuck them under a powerful enogh scope......next time!


Steve, would love to see that Bolezky ref!!!!!!!!!! Will look up the others too!

J

 

[Steve O'Shea]

Don't try to engage my enthusiasm...I haven't got one!

... how does $500 sound for a couple of clusters of Sepioloidea 'pacifica' eggs? If the RV Munida does any deep-sea'ish dredging this summer and collects clumps of eggs of the very large new species of Sepioloidea that occurs down there I'll give you another $500. I just need them overnight couriered to Auckland, and will give you co-authorship on the developmental/embryological papers that result from it (culture first and foremost, embryology secondarily).

What say yee Jean?

We're off diving again next weekend - hopefully we'll get some Sepioloidea pacifica ourselves, but they're few and far between up this way.

We could get these papers done by early next year. Engaged any enthusiasm?
Ta
O

 

[Jean]

Enthusiasm engaged! I'll have a chat to Chris (Munida's skipper)! I'll also put the word around the fishers too (via Adelle our aquarist, her Dad and Brother have a fishing boat! and she caught the specimen of the new one I have!) We have some deep dredging scallop fishers round here.

J

 

[Fujisawas Sake]

Uh, I spent the entire afternoon today looking at prepped slides of 16 day old O.rubescens and I have to say that these "koliker bristles" did not have any apparent nerve attachments. I may be wrong, but I looked for any of the typical dermalogical neurons and saw no clear attachments to the bristles. There were four slides of sequential cross-sections from four different juveniles.

Considering the last work done in this was nearly a century ago, has any followup histological work been done? Could it be that Chun was wrong?

John

 

[Steve O'Shea]

John, there is such a fascinating paper in this!!!!

You MUST publish these findings!!!!

 

[Jean]

John, there is such a fascinating paper in this!!!!

You MUST publish these findings!!!!

John YES DO!!!

J

 

[Fujisawas Sake]

Steve, Jean...

Check your PM's...

&

John

 

[Jean]

Steve, Jean...

Check your PM's...

&

John

Done!

j