horned baboon spiders

[syndicate]

ok why do these tarantulas have the horns on there carapace?what are they for?does anyone even know lol?
my c.marshalli is startin to get a nice horn coming in now and the t is looking awesome.been trying to think about this lately tho as to if the tarantulas evovled into growing the horn and why.can anyone fill me in here?

 

[lucanidae]

No official paper has been published on this topic. However, leading hypothesis that I've heard include,
"Helps the spider stay in the burrow when under attack"
"Food and/or water storage"
"Mutation in internal support structure caused fovea to turn outward"

As of now, any "definite" answer you find is not actually definite.

 

[syndicate]

cool thanks for the info!

 

[jwasted]

good info there thanks for reply to his question>. I was also wondering that.

 

[Ewok]

I also have my own scientific theory a number of animals in Africa have horns, andthe tarantulas were jealous of the other animal's horns and fell under the peer presure and grew thier own.

 

[Scolopendra55]

This is something I've been wondering as well :?

 

[ShadowBlade]

They have 'em to make dumb humans like us ask questions.:wall: :wall: :wall:

 

[T.Raab]

Hi,

Rick West drop some years ago a notice in a newsgroup about this topic:

"Back in mid-1986, I did a preliminary study of the 'foveal horn' from dissected Ceratogyrus spp. The results of this investigation were published in both the South African Spider Club Newsletter 2/3 and later in the British Tarantula Society Journal. Basically, I surmised that the foveal horn evolved to serve two functions; 1) it provided an increased surface area for the attachment of the dorsal dilator muscle (a powerful muscle attached to the top of the 'sucking stomach) which aids in drawing in liquified nutrients at a faster rate (sort of an eat and hide) and 2) it provided and increases area for the midgut diverticula to expand into during times of engourgement of nutrients or water .... basically allowed for more nutrient storage .... possibly aiding in it's adaptability to survive longer periods of drought in more arid regions."

This explanation sounds coherent to me.

 

[Karmashadowsh]

great info.

that is some grat info...i dident know how "special" that horn was to these tarantulas.very interesting,thank you for the info and letting us be more aware of just what these sp. have underneeth some "wierd" looking horn

 

[lucanidae]

Yes, Rick West is one awesome guy and the explanation sounds good, but you have to remember, it's a

I did a preliminary study

. As far as I know, it hasn't been tested yet. I can't wait for another paper to come out on the subject.

 

[T.Raab]

Hi,

As far as I know, it hasn't been tested yet

tested what?

"Helps the spider stay in the burrow when under attack"

BTW: This is totally <EDIT>. - I never saw that a Ceratogyrus sp. was using the foveal protuberance when they are "under attack".

 

[Crimsonpanther]

Wow ...thats some awosme info....
I would definatly like to find out more ...

 

[lucanidae]

Quote:
As far as I know, it hasn't been tested yet

tested what?


Quote:
"Helps the spider stay in the burrow when under attack"

BTW: This is totally <EDIT>. - I never saw that a Ceratogyrus sp. was using the foveal protuberance when they are "under attack".

The hypothesis that Rick West came up with, it hasn't been tested yet. You can't dissect one T, come up with a hypothesis, and then publish and call it "truth." You would have to run expieriments to see whether or not they do have more sucking stomach power, and/or if they do store more food/water in that area.

As for "Helps the spider stay in the burrow when under attack" I found this in a book containing a lot of Pocock's notations. It was his, "hey whats this horn thing, it might be good for this..." He also noted thier lack of thickend rear legs that many OWs use for plugging up the entrance to a burrow. Have you even seen a Ceratogyrous under attack by a mouse or other small rodent it its native environment?

Personally I don't think that it is what the horn is for. Think of it this way, if it was for staying in the burrow, why would some point forward, backward, and up? To test that you would have to see if different Ceratogyrus sp. turned different ways when under attack. Thinking of it this way is much more productive then saying "this is <EDIT>, because I've never seen it."

 

[syndicate]

Hi,

Rick West drop some years ago a notice in a newsgroup about this topic:

This explanation sounds coherent to me.

nice one!thanks for posting that

 

[lucanidae]

The only thing that gets me about that drawing is that the horn is pointing backward but mostly upwards. On more extreme forward or backward pointing species/specimens, I wonder if bending a muscle back around a curve really ends up helping the stomach at all. I mean, one way should work better than the other, so why both???

Also

midgut diverticula to expand into during times of engourgement of nutrients or water ....

So this supposed to help during drought or long periods without food? But I don't beleve that food/water would spend that much time in the midgut, it must travel through to be absorbed. I thought food/water would be stored in the abdomen. It isn't like Ceratogryrus can't expand their adbomens like any other genus, so why would this relatively small area provided by the horn really make a difference?

 

[Scorp guy]

to revive an old thread, id like to chime in.

From what i've gathered and read, it does nothing at all, expet in C. darlingi, it MAY reduce wind resistance. Truly fascianting creatures.

 

[syndicate]

aerodynamics

 

[Scorp guy]

you could say that. Yeah, kinda like a giant spider-car with a spoiler.

 

[Gigas]

Why would it need lowered wind resistance?????

 

[syndicate]

dont quote me on this but arent some of the ceratogyrus very fast?i havent seen my c.marshalli sprint yet but a member of this board told me one of the fastest t's he ever saw was one of the horned sp run across his kitchen floor lol