Jump to content

Tooth Cross-Section


Harry Pristis

Recommended Posts

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.

post-42-0-15987900-1419367666_thumb.jpg

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.

post-42-0-55607500-1419367692_thumb.jpg

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?

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

Link to comment
Share on other sites

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

Every once in a great while it's not just a big rock down there!

Link to comment
Share on other sites

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)

post-1240-0-37418500-1419385898_thumb.jpgpost-1240-0-28215400-1419385895_thumb.jpg

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

Regards, Chris

Link to comment
Share on other sites

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.

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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.

post-1240-0-45174600-1419646919_thumb.jpgpost-1240-0-47397000-1419646921_thumb.jpg

Regards, Chris

Link to comment
Share on other sites

  • 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.

post-1240-0-46920800-1420341763_thumb.jpgpost-1240-0-57422400-1420341765_thumb.jpgpost-1240-0-76419600-1420341767_thumb.jpg

Regards, Chris

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...