A chunk of jaw with a broken tooth

[Shellseeker]

When I am hunting, and there is a lot of interesting material and I am running out of time, I over_collect.  Anything that looks fossil gets taken for later review. Most of it is unidentifiable bone that gets tossed or donated.

This fossil is one of those,  but I am thinking that even as broken as it is, it might be interesting. The 1st photo is looking directly down on the chewing surface.  At first, I thought no way will I ever identify this tooth.  But now I am getting hope.  The photo of this tooth is directed left to right along the jaw line of the animal. I am thinking that my thumb is on the tongue side of the jaw. An unusual thing is that the tooth is an hourglass shape, and the length of the tooth running down the jaw is shorter than the width across the jaw.  The half hourglass on top is 14 mm and the lower half is 10.5 mm . I am already thinking sloth, glyptodont, giant armadillo..

 

If you look at the above photo, the left side of the fossil looks like this !!!! The tooth not present has left vertical grooves in the jaw. I have seen similar grooves in the broken fragments of Glyptodont jaws. but the shape of the tooth does not say Glyptodont to me.  That seems good enough for a start.  Help !!!  @Harry Pristis, @digit @Brett Breakin' Rocks @Thomas.Dodson @Plantguy @PODIGGER There is an answer somewhere here..

 

Additional photos:

 

 

[PODIGGER]

Wish I could help Jack. Unfortunately, I haven't run across that hourglass shape.  I am sure somebody else has!  Good Luck,

 

Jim

[Thomas.Dodson]

Unfortunately, I can't help. Interested to see what others have to say though, neat find.

[Harry Pristis]

Aenocyon has hour-glass compressed molars, like some other carnivores.  But, that's not a guess, just an observation.

 

 

 

[Shellseeker]

12 minutes ago, Harry Pristis said:

Aenocyon has hour-glass compressed molars, like some other carnivores.  But, that's not a guess, just an observation.

Thank you, Harry. 

It gives me a direction to explore.  I had not realized the directional nature of the M1s of the predators, especially Dire Wolf.. Some time this evening, I will likely send a request for ID from Richard Hulbert,  but I wanted to do as much digging as I could before.

[digit]

I'm at the beginning of the learning curve for interesting mammals from the Peace River but I tend to lean toward sloth (i.e. Megalonyx type) teeth when I see this hourglass shape. I'd be expecting Glypotherium and Holmesina to be a bit smaller than this but I wouldn't give up pursuing the Xenarthran line of inquiry. Then again, I'll defer to just about anybody who was more experience with these rarer fossils.

 

 

Cheers.

 

-Ken

[Plantguy]

Hey Jack, I unfortunately have nothing to add but to say I like this kind of mystery. Looking forward to what Dr. Hulbert says. Harry's observation/insight is intriguing. 

Regards, Chris 

[Searcher78]

Probably not it, but a sloth tooth can give a figure 8 appearance when broken.

[Bronzviking]

That's an interesting fossil Jack! Looking at your first photo my initial thought was Sloth tooth.

[Harry Pristis]

The tooth has at least one feature which resembles sloth:  no pulp cavity exposed (right, Jack?  The more I look at the image, the easier I can imagine a central pulp cavity filled with sediment.)  The tooth seems to have an outline too pinched to be sloth.  Sloth teeth are peg-like with no split roots.  Here are some examples from my collection:

 

root view

 

 

 

[Shellseeker]

9 hours ago, Harry Pristis said:

The tooth has at least one feature which resembles sloth:  no pulp cavity exposed (right, Jack?  The more I look at the image, the easier I can imagine a central pulp cavity filled with sediment.)  The tooth seems to have an outline too pinched to be sloth.  Sloth teeth are peg-like with no split roots.  Here are some examples from my collection:

 

Harry,

I agree with your points, but more and more it seems like sloth to me .  I keep trying to get clarifying photos. Those 2 scalloped cavities seem natural.

 

This is the side view of a P. garbani jaw from the same location.

 

The vertical texture seems the same, but the horizontal grooves are another feature that I have not previously seen.

 

 

[Shellseeker]

Richard Hulbert is amazing, which might be the result of studying Florida fossils for the last 40 years... He is a treasure.

Quote

    I think this is a fragment from the posterior portion of a mandible from a tapir. The root embedded in the jawbone is the posterior root of the third molar. A portion of the alveolus for anterior root is preserved. With this interpretation, the actual tooth length would have been greater than its width. The ID of tapir is based on the cross-sectional shape of the preserved root. The third molars of most other herbivores such as peccaries, llamas, bison, and horse have an extension to the posterior end of the tooth, which is also expressed in the shape of the root. Tapirs do not have such a feature on their third molars.

Richard

 

Not only identifies the animal, but the exact tooth...

[Bronzviking]

2 hours ago, Shellseeker said:

Richard Hulbert is amazing, which might be the result of studying Florida fossils for the last 40 years... He is a treasure.

 

Not only identifies the animal, but the exact tooth...

That's awesome Jack! Nobody guessed that one, Lol. Congrats!

[Harry Pristis]

I'm having trouble matching your images with my tapir m3 cap.  As I interpret your images, the tooth would have to be in the jaw sideways to be a tapir molar.  Tapir lower molariform teeth have spade-like roots below the lobes which represent the cusps.  Can you set me straight, Jack?

 

 

[Shellseeker]

3 hours ago, Harry Pristis said:

I'm having trouble matching your images with my tapir m3 cap.  As I interpret your images, the tooth would have to be in the jaw sideways to be a tapir molar.  Tapir lower molariform teeth have spade-like roots below the lobes which represent the cusps.  Can you set me straight, Jack?

I believe we are dealing with the M3,  maxilla.  Look at my original 1st 2 photos. the 2nd photo is on the left of the 1st, going toward the lips.

EDIT: I was way too cryptic in my response.

Clarity:.  The M3 has 2 alveoli . The root embedded in the jawbone is the posterior root of the third molar. A portion of the alveolus for anterior root is preserved.

The posterior root of the 3rd molar has an hourglass alveolus.  The ID of tapir is based on the cross-sectional shape of the preserved root.

and the tapir is relatively unique in local mammals: The third molars of most other herbivores such as peccaries, llamas, bison, and horse have an extension to the posterior end of the tooth, which is also expressed in the shape of the root. Tapirs do not have such a feature on their third molars.

Edited May 21, 2021 by Shellseeker

[Plantguy]

Jack, Its really cool to have an answer. I wonder if there are others like me that you made me go look at their tapir teeth. And I think I see the same posterior root cross sectional shape/structure yours has...Very Neat! Thanks for the education. 

Regards, Chris 

[Harry Pristis]

Thanks for the elucidation, Jack.  Now, I have a new interpretation of your images.  I was thinking that the root remains was the entire root system, not just half of it.

 

Hulbert said this was a mandibular tooth.  When you say it's maxilla (M3), are you saying that Hulbert is wrong?!

 

1 hour ago, Shellseeker said:

I believe we are dealing with the M3,  maxilla. . . .

 

I agree with Hulbert -- tapir mandible (m3).  

 

 

 

 

 

 

[Shellseeker]

51 minutes ago, Harry Pristis said:

I agree with Hulbert -- tapir mandible (m3).  

Just an error .  I am just barely smart enough not to disagree with Hulbert.  How are you differentiating ?  Richard does not seem to state why it has to be mandible rather than maxilla.

Forget that last question. The surrounding material is clearly mandibular.

Edited May 21, 2021 by Shellseeker

[digit]

It's nice to have an Oracle to go to for Florida fossils. We actually have quite a few here on the forum including our go-to @Harry Pristis who has such a great library of images to help illustrate IDs. Richard, as you mentioned, has been immersed (possibly saturated) in Florida fossils for decades and Miocene-Plio/Pleistocene mammals are at the core of his knowledge base.

 

It's great to be able to obtain a concise and well-reasoned ID and also to archive our thought process (and surprising conclusion) here on the forum for others to see.

 

 

Cheers.

 

-Ken

[Harry Pristis]

10 hours ago, Shellseeker said:

Just an error .  I am just barely smart enough not to disagree with Hulbert.  How are you differentiating ?  Richard does not seem to state why it has to be mandible rather than maxilla.

Forget that last question. The surrounding material is clearly mandibular.

 

Differentiating between upper and lower teeth (molars, molariforms) of mammals is often easy.  In perissodactyls such as horses, rhinos, and tapirs, the shape of the crown (squarish vs. rectangular) is a giveaway.  As for the roots of perissodactyls, the lowers have two "fangs" while the uppers have four (often missing in isolated fossil teeth).

 

Hulbert probably recognized what I didn't: the double-fang form of the alveola.  Two fangs in line = mandible.