Sticking scute seams don't usually just happen because of low humidity but from a combination of low humidity and not doing any growing for an extended period of time. Both together don't usually happen in the wild but it's possible.
The problem with lack of humidity in captivity is that small tortoise can dehydrate over night if not humid enough. This does damage to the liver and kidneys and if it happens enough it can compromise these organs and make it so they don't function properly. This makes it hard to take the nutrients needed out of the food received. This in turn would make a good diet inadequate and to low in nutrients needed. This would in turn contribute to the pyramiding.
Danny
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