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Harry Pristis

I've come close to putting this giant armadillo jaw into my scraps box each time I looked at it in the past. It's too good to throw out, yet it doesn't have much collector appeal.

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This morning it occurred to me (whence come these inspirations?) that this jaw is unique in one way: It reveals the cross-section of a tooth (second from the last tooth) in the mandible. Ho-hum you say. Well, armadillos like all xenarthrans have hypselodont teeth; they are peglike, open-rooted, and continuously growing. In cross section they don't look like horse or bison or dire wolf teeth.

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Lacking a branch-like or hooked root, teeth of an otherwise-preserved armadillo jaw are likely to fall out of the alveoli. It is common for a fossil jaw to be edentulous.

Amadillo teeth have no enamel. They grow continuously, they had to. Without enamel, they would have worn pretty quickly. They are open-rooted; that is, the tooth pulp-cavity was not closed as in many other taxa of mammals. Think of the continuously growing incisors of rodents and lagomorphs but without the enamel.

The term used to describe this condition is "hypselodonty" and is usually applied to mammal teeth. The term describes teeth that are open-rooted and ever-growing. Hypselodont teeth are found in xenarthrans, rabbits, some rodents, and a few ungulates, according to Hulbert's book.

Anyone have an interesting cross-section to share with us?

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If you're going to throw that in the scrap box Harry, I'll send you my address lol. It's still on my list! :P

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Hey Harry, too many cool things you have!

I'm still in the infancy of vertebrate collecting as you know. This ain't much but I believe this is a little part of a cusp from a Tapir tooth...(Mio/Plio-Pleistocene, Hillsborough County, FL)

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I always thought it was interesting in cross section although a partial/broken but I've certainly not seen many teeth!

Regards, Chris

Edited by Plantguy
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Harry Pristis

Good images, Chris! Interesting cusp from a tapir lower. The tooth is unerupted -- unfinished, really. The enamel crown develops from the outside in, so that the enamel cap is an exquisite adult crown.

  • I found this Informative 1
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Good images, Chris! Interesting cusp from a tapir lower. The tooth is unerupted -- unfinished, really. The enamel crown develops from the outside in, so that the enamel cap is an exquisite adult crown.

Cool, appreciate the info Harry. Thank you! Regards, Chris

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Harry, here's another scrap showing a section thru a camel/llama molar? not sure that there is enough there to say definitely? It sure doesnt seem very sturdy. Again, a Mio/Plio-Pleistocene creek find.

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Regards, Chris

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  • 2 weeks later...

Been messing with Florida Mio/Plio/Pleistocene shark teeth lately and took this shot of the interior of a partial Mako...not terribly exciting but there is an interesting texture there.

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Regards, Chris

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Thanks for the infom Harry. Funny how the tooth looks jst like a belemnite in cross section...

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