# Pyramiding Plastron



## Tom (May 31, 2010)

I think most everyone is aware of my obsession with learning all there is to know about pyramiding. One of the things I still don't know is the exact mechanism behind it. Is it the actual bone and the keratinous layer just changes shape with it, or is it just the keratinous layer and the bone underneath is normal?

Anyhow, something I've been pondering is: How come the plastron scutes don't pyramid? Even the worst cases of the most prone species still have a smooth plastron. What's the difference between plastron scutes and carapace scutes?


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## terracolson (May 31, 2010)

guessing here...

that part of the shell was designed to grow long ways and stay flat. when a top is to grow up and around. and would be the more flexible of the two

also
you have erosion that would happen, a constant pressure on it. weight on it

i also have no idea, i am just guessing


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## Yvonne G (Jun 1, 2010)

Well, the plastron doesn't actually "pyramid" but it does grow strangely in a pyramiding tortoise. All sorts of weird designs, swirls and ridges.


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## GBtortoises (Jun 1, 2010)

"Well, the plastron doesn't actually "pyramid" but it does grow strangely in a pyramiding tortoise. All sorts of weird designs, swirls and ridges."

Along with the above description many tortoises that I've seen with severe pyramding also have plastron scutes that are to some degree, indented. Some of the with very thick edges where they protrude around the leg and head openings.


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## stells (Jun 1, 2010)

Then you have the ones where the plastron grows to long for the body...


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## moswen (Jun 2, 2010)

GBtortoises said:


> "Well, the plastron doesn't actually "pyramid" but it does grow strangely in a pyramiding tortoise. All sorts of weird designs, swirls and ridges."
> 
> Along with the above description many tortoises that I've seen with severe pyramding also have *plastron scutes that are to some degree, indented.* Some of the with very thick edges where they protrude around the leg and head openings.



my little moswen came to me with his plastron scutes indented and a thick area where the scutes meet that gives you a mental image of someone hot glueing the edges together and the hot glue coming out.... i figured that was part of the plastron pyramiding because he had already begun pyramiding on his carapice.


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## jackrat (Jun 2, 2010)

Maybe the plastron gets more moisture from the substrate than the carapice ,due to it's location.


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## Scooter (Jun 2, 2010)

My first thought when I read this was the same as Terra's that the plastron is in more constant contact with things (the ground) and gets rubbed and worn more


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## Annieski (Jun 4, 2010)

From the info I have read about torts, since getting Morty, the best way to relate the info is to Compare to human anatomy. The shell is directly related to human skin[just in a different form] and is primarily compose of Keratin[a protein based substance] which can be soft or hard depending on primary function[skin on humans softer than fingernails but part of the same anatomy system]. Inside this protective shell is the skeletal system, which in many instances, the bones are named the same as in humans[there is the large bone in the thigh that is called the femur in both species]. In humans, all bones have "growth plates" which allow us to "reach" our adult stature. As the bones grow so does everything else[hopefully in proportion]. In the skull, there are 8 bones that protect the brain. At birth, these bones are separated by pieces of cartilagenous type tissue[reason why baby's head is so soft a birth]. The bones of the skull don't completely fuse until about the age of puberty. This is the best correlation to the shutes on the tortoise shell. The shutes, carpase,plastron and bone,it would seem, all need to grow at the same rate or similarly in proportion for all to be well.
IMO


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