Worn Horse Jaw Section?

[Mtwombly]

Hey guys, I’m hoping someone can help me out by confirming the ID on this odd fossil I found in the Peace River! It is a very worn section of jaw bone with 3 teeth showing. The teeth appear to be that of an equine, so I assume what I have here is a section of an equine jaw worn by water and time. The shape of it is odd, though. 

[Carl]

It certainly seems to be at least an herbivorous mammal jaw. But the presentation is VERY odd for the Peace River. Never seen something preserved like that from there.

[Harry Pristis]

Aren't these deciduous teeth.  Young horses are not immune to attack (or scavenging) by 'gators.  My guess is that this is a 'gator coprolite.  A 'gator would shred a large mammal before swallowing chunks of flesh.  'Gators don't chew, and they are not equipped to spit out the hard parts.  Rare find!

[Mtwombly]

3 hours ago, Harry Pristis said:

Aren't these deciduous teeth.  Young horses are not immune to attack (or scavenging) by 'gators.  My guess is that this is a 'gator coprolite.  A 'gator would shred a large mammal before swallowing chunks of flesh.  'Gators don't chew, and they are not equipped to spit out the hard parts.  Rare find!

Oh wow. That is too cool! I looked up florida crocodilian coprolites and I see exactly what you mean. That’s very exciting  Thank you so much for your help. 

Edited February 7, 2022 by Mtwombly

[garyc]

That is some spectacular poop!

[Coco]

Hi,

 

@GeschWhat

 

Coco

[fifbrindacier]

It's worth to present it in the post "finds of the month entries".

Neat find !

[fossilhunter21]

Congratulations on such an awesome find!

 

That is so cool!

 

-@fossilhunter21

[Al Dente]

Unlikey to be a croc or gator coprolite since they have strong digestive system that breaks down bone. Fossil croc coprolites are known for their uniform clay-like consistency that lack all traces of their meals. I’m guessing this is a concretion that formed around part of the horse’s jaw after it was buried and partially crushed by compaction of the sediment.

[Harry Pristis]

9 hours ago, Al Dente said:

Unlikey to be a croc or gator coprolite since they have strong digestive system that breaks down bone. Fossil croc coprolites are known for their uniform clay-like consistency that lack all traces of their meals. I’m guessing this is a concretion that formed around part of the horse’s jaw after it was buried and partially crushed by compaction of the sediment.

It's true that 'gator coprolites are usually of a clay-like fineness.  Isn't that what we see making up most of this toothed example? I once collected a 'gator coprolite with a complete deer proximal phalanx embedded in its center.  Unhappily for this discussion, I sold that example.

 

I'm sure with this toothed example that the interior structure of the jaw has been digested, allowing the collapse of the exterior of the jaw.  The enamel of the teeth resisted digestion, though the cementum is gone.  The shape of the object is unmistakable.  The guess of compaction and concretion just doesn't fit the Peace River sediments in my experience.

[Al Dente]

The matrix around the teeth looks sandy. Croc and gator coprolites are fine grained, almost clay-like. It would be very unusual for the teeth to be lined up in their original order after the bone has been mostly digested and churned up in the stomach and intestines.
 

 

Edited February 8, 2022 by Al Dente

[Harry Pristis]

51 minutes ago, Al Dente said:

The matrix around the teeth looks sandy. Croc and gator coprolites are fine grained, almost clay-like. It would be very unusual for the teeth to be lined up in their original order after the bone has been mostly digested and churned up in the stomach and intestines.

The Peace River is shallow and loaded with sand.  It's unreasonable to think that 'gators don't ingest sand when thrashing about to dismember large prey items.  But 'gators don't digest sand.  Sand just passes through, along with other incompletely digested items. 

It's also unreasonable to argue that you know what all 'gator coprolites are like.

Reptiles, specifically 'gators, don't "churn" food -- you must be thinking of ruminants.  Reptiles rely on strong digestive acid and peristalsis to process food items.

But, you're correct about one thing:  This is a very unusual fossil.  Rare, even. Something held the teeth in close-to-life position.  What else but the jaw bone plus a tightly packed alimentary canal.

[Lone Hunter]

Just wanted to throw in my two cents, having worked around alligators when I was volunteering at the Dallas zoo many years ago I learned quite a bit about them,

having two stomachs, the first containing gizzard stones the second with acid virtually nothing passes through intact or undigested. However, like a lot of animals they will vomit if stressed or if temp drops too low for them to digest their meal, it would seem more likely this may be regurgitate.

 

Edited February 8, 2022 by Lone Hunter

[BullStrong]

So very interesting! The size and shape does strongly suggest coprolite and according to this study of crocodilian coprolites: A Study of Crocodilian Coprolites from Wannagan Creek Quarry (Paleocene- North Dakota): Ichnofossils II (smm.org)      205 coprolites were studied, 69 contained inclusions, and some appear to be gar scales. The study also cites past studies that found inclusions of frog bones, small croc bones, stones and teeth. So clearly bones and teeth can pass through a crocs digestive system. Higher resolution magnified images of the specimen may offer more clues like smaller identifiable inclusions or evidence of it being a fossil embedded in a water worn limestone rock. Awesome find regardless!

 

 

 

[Al Dente]

9 hours ago, BullStrong said:

So clearly bones and teeth can pass through a crocs digestive system.

I’ve read this publication a while back and it doesn’t really address what criteria he uses to differentiate which coprolites belong to crocodiles and how he excluded other animals. He falsely describes Champsosaurus as an alligator which is wrong. It is a reptile that superficially resembles alligators and crocodiles and might have a different digestive process from alligators and crocodiles.

 

 

[Al Dente]

Modern studies of alligator and crocodile feces usually mention that bone does not survive the digestive process. Here’s one example:

 

 

[RuMert]

1 hour ago, Al Dente said:

He falsely describes Champsosaurus as an alligator

I didn't read the publication, but from that quote alone doesn't follow that Champsosaurus is considered an alligator, it could mean a simple enumeration like Champsosaurus, alligator, croc, etc

[Harry Pristis]

Lone Hunter introduces a new idea:  the fossil is regurgitate -- it was never fully processed in the gut.  Carrying that idea a bit further, perhaps the toothed fossil is a cololite, petrified stomach contents.  Again, the meal was not fully processed in the gut. 

  Imagine the gator that swallowed the horse jaw was injured in a scrum over the horse carcass . . . infection . . . death . . . burial . . . preservation . . . recent exposure and disintegration in the high-energy Peace River.  The cololite scenario does answer the objections to other explanations. 

[Al Dente]

10 hours ago, RuMert said:

I didn't read the publication, but from that quote alone doesn't follow that Champsosaurus is considered an alligator, it could mean a simple enumeration like Champsosaurus, alligator, croc, etc

I think you are correct. I read it wrong. The author probably isn’t referring to Champosaurus as an alligator.

Edited February 9, 2022 by Al Dente

[Plantguy]

Absolutely remarkable find! Might want to send a photo up to Dr. Hulbert at UF to get his thoughts. 

Regards, Chris 

[BullStrong]

After reading this very thorough publication on crocodilian scatology: Crocodilian Scatology, Microvertebrate Concentrations, and Enamel-Less Teeth on JSTOR ,  , the coprolite/fossil in question can more plausibly be a coprolite and could be confirmed as a crocodilian coprolite if the teeth are without enamel or mostly so.  

[Harry Pristis]

Interesting to read.  Thanks, BullStrong.  I note that the study dealt with microfaunal remains.

 

The paper argues that decalcification of enamel and dentine takes place in the fundus (the upper portion of the stomach).  If BullStrong's paper results can be applied to large animal teeth, it suggests that the toothed fossil did not spend much time in the 'gator gut.  I say that because the enamel and visible dentine is evidently not affected.  The cementum, which shrouds horse teeth in life, is missing.  This "short duration" possibility accommodates both the "regurgitate" and the "bololite" scenarios.

 

Either it was a short exposure to the strongest gastric acids, OR the cementum was extra-resistant to the acids, allowing time for the supporting bone to be seriously attacked.

 

We're having fun now!  

[Lone Hunter]

I agree this couldn't have spent much time in the stomach,  it looks unaffected by gastroliths or acid. I don't think it would even be able to pass from muscular to glandular stomach. Inclusions cited in the papers referred to were on the micro level, small meals are digested fast, and the hotter the temperature the faster it's digested, so small bones or single tooth can pass through digestive tract without further breakdown.  Another scenario,  if a gator is chomping on a horse head to get it in to manageable peice to swallow a chunk could break off and end up buried in sediment. 

[Mtwombly]

I love this discussion! Thank you all so much for such valuable information. I truly appreciate it and have learned a lot while researching this fossil with your help. I will work on taking some better, higher resolution photos and I will post them here. Some quality keeps getting lost in the process of uploading the photos I’ve taken with my phone and the details are slightly blurry. I’ll get out the camera!