Potential Evolutionary Path of Metasepia

Phil1078

Blue Ring
Registered
Joined
Aug 16, 2010
Messages
45
Reaction score
2
So Mr. Ross' flamboyant cuttlefish got me thinking. In Metasepia we really get a glimpse of some of the environmental pressures that lead to the octopus. If I am not mistaken, the cuttlebone is greatly reduced. Metasepia is supposed to tire of swimming more easily. There is also an adaption to walking. Now what I find really interesting on this new take on the octopus' way of life are the little stalks or papillae (I am not sure what to call them) that are located on the ventral side of Metasepia's mantle. Could this eventually lead to a 12 legged octopus-like cephalopod? The muscular, mollusc foot evolved into legs, so perhaps the mantle will too. It seems analogous to the "thumb" of pandas, which is really a separate hand bone (I believe the sesmoid). Anyway, I am not the most well versed in cephalopod evolution, so please correct me if my speculation is way off.
 

cuttlegirl

Colossal Squid
Supporter
Joined
Sep 16, 2005
Messages
4,936
Reaction score
255
Location
Pittsburgh, PA
I so wish Monty were still around to answer this one... Development of the arms occurs from the same group of embryonic cells in cephalopods - I have an article that I will try and find... - so the papillae will not evolve into more legs.
 

kpage

Wonderpus
Registered
Joined
Jun 24, 2009
Messages
214
Reaction score
0
wow... I just read what happened to Monty... Must have missed it because of my job. That's terrible.

sorry to detrack the thread
 

cuttlegirl

Colossal Squid
Supporter
Joined
Sep 16, 2005
Messages
4,936
Reaction score
255
Location
Pittsburgh, PA
Ok, here's the title of the paper...
Evolution of the Cephalopod Head Complex by
Assembly of Multiple Molluscan Body Parts:
Evidence From Nautilus Embryonic Development
Shuichi Shigeno,1* Takenori Sasaki,2 Takeya Moritaki,3 Takashi Kasugai,4
Michael Vecchione,5 and Kiyokazu Agata1
I have the full paper, but it is not for redistribution, but if you are a biologist and interested, I will find a way... PM me. It is a really complex paper, I will try to summarize it after I re-read it...
 

Stavros

GPO
Registered
Joined
Jun 26, 2008
Messages
168
Reaction score
38
Location
American University of Kuwait
cuttlegirl;162085 said:
Ok, here's the title of the paper...

I have the full paper, but it is not for redistribution, but if you are a biologist and interested, I will find a way... PM me. It is a really complex paper, I will try to summarize it after I re-read it...
I like the fact that Cousteau was saying this back then.

Two larger arms act as a hood, and fold back over the nautilus' back. They serve as a covering for the opening of the shell when the nautilus is in hiding and are rather like the leather-like hood used by some shell animals for the same purpose.
Octopus and squid, the soft intelligence
JY Cousteau, P Diolé - 1973 - Doubleday Books
 

Level_Head

Vampyroteuthis
Registered
Joined
Jun 10, 2010
Messages
266
Reaction score
20
Hmm. I'm not sure that it's a question of papillae evolving into more legs. The flamboyant seems to walk on muscular extensions of the mantle. I had at first though that these were modified swimming fins, but the fins are still present (though very diaphanous) and still used for swimming.

The walking process uses muscles, not just the apparently more "passive" extension of the skin protrusions. It would be interesting to see a diagram of the ventral mantle musculature of this creature.

I'd be inclined to agree with Phil1078; this development does seem to be walking the path, so to speak, of a different mode of locomotion.

It's interesting to me that the flamboyant cuttlefish seems best equipped of all the cephalopods to stride out onto land. Those muscular protrusions are seemingly steerable, stretchable and flexible (though they obviously don't have to bear much weight in his current environment) -- it would be intriguing to see where evolution could take this animal.

I can picture a sort of quadruped stance based on extensions of the mantle, short and sturdy, with all of the current arms and tentacles available for food capture and perhaps, eventually, tool-building. Every "land based cephalopod" concept I've seen had them walking on the arms, though often with some specialization. This is a new possibility.

Are there any other cephalopods with this sort of pseudo-articulated mantle musculature?
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,646
Reaction score
1,813
Location
Gainesville, GA
... or could it be that they never developed the swimming structures of their cousins and the "leg" fins are remenents of land life?
 

Level_Head

Vampyroteuthis
Registered
Joined
Jun 10, 2010
Messages
266
Reaction score
20
I don't know -- that loss of functionality is not easy to definned.

Hmm. The occasional above-water excursions by octopuses work as long as their gills are kept wet, I understand. There is another creature that emerged from the sea long ago but now is entirely terrestrial, and it too must keep its breathing apparatus wet: the spider. They use "book lungs" with openings underneath, and they've evolved elaborate mechanisms (especially the desert types) to keep those surfaces moist.

Perhaps our cephalopods might do something like this.

Hey, a genetic researcher who specialized in manipulating genes to create new cephalopod body parts for operating above water -- would she be an octogenairian?
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,646
Reaction score
1,813
Location
Gainesville, GA
Hey, a genetic researcher who specialized in manipulating genes to create new cephalopod body parts for operating above water -- would she be an octogenairian?
"D" Grabs silver cross and runs backward emphatically saying, no, no, no

I just read at least one articles about whales having been land animals as evidenced by fossils and don't remember the source (likely started with something here) but here is a quick summary of the findings

The significant difference would be that whales remained lunged air breathers with modified intake and exhaust. It does not take much to envision this guy trundling about on land but I have no idea if we have seen gilled animals in a reverse engineered evolution.
 

Members online

Forum statistics

Threads
20,282
Messages
204,765
Members
8,892
Latest member
kyledkserra

Monty Awards

TONMOCON IV (2011): Terri
TONMOCON V (2013): Jean
TONMOCON VI (2015): Taollan
TONMOCON VII (2018): ekocak

About the Monty Awards
Top