predator/scavenger puncture marks ???? in an Oligocene tortoise carapace

[MarcoSr]

I was looking closely yesterday at my tortoise (Stylemys nebrascensis from the Oligocene Brule Formation) that I found on my sons’ M&M Ranch in Nebraska that finally made it to my home in Virginia this Saturday.  You can check out the two below links which describe finding it and the four year time-frame to get it home to Virginia:

 

http://www.thefossilforum.com/index.php?/topic/65393-oligocene-tortoise-from-the-mm-ranch-in-crawford-nebraska/&

 

http://www.thefossilforum.com/index.php?/topic/98983-my-stylemys-nebrascensis-tortoise-from-the-oligocene-brule-formation-of-nebraska/

 

I could see a number of rounded holes on the carapace.  I started to measure the distance between the centers of the holes and determined that there were four pairs of holes with 45mm spacing between centers of three sets of holes and 44mm spacing between centers of the fourth pair.  I don’t think that this could be coincidence so I believe that the holes may be puncture marks from the canines of a predator/scavenger.  Below are pictures of two sets of holes:

 

 

 

Do TFF members think that these are puncture marks from a predator/scavenger?

If so, what animal or animals could have made them?

 

I looked at skulls found on my Virginia property from extant mammals like skunks, possums, raccoons, coyotes etc.  Most were under 23mm canine spacing.  The coyote skull had the largest canine spacing at 40mm.  So if the marks on the carapace of my tortoise are from a predator/scavenger it was a decent sized animal.  My sons have the skulls of a good number of the predators/scavengers from that Oligocene time period.  I’ll have them check the canine spacing.  They have 6 or 7 saber cat skulls and I’ll have them check the saber spacing also.

 

Marco Sr. 

Edited July 2, 2020 by MarcoSr
not as confident "are" to "may be"

[jpc]

A lot of modern turtles have diseases that eat into the shell.  These could be either that or predator marks. 

[MarcoSr]

9 hours ago, jpc said:

A lot of modern turtles have diseases that eat into the shell.  These could be either that or predator marks. 

 

Thank you for letting me know about the diseases that modern turtles have.

 

Do you know what Oligocene predators/scavengers, if any, might have 45mm spacing between canine tips?  If there aren't any currently known than that would eliminate predator/scavenger marks.

 

There weren't many noticeable rounded holes in the carapace.  Most fit into four sets of two with 45mm (one was 44mm) spacing between centers.  I would expect more holes and random spacing if from disease.  Edit: seeing the below carapace picture I'm thinking disease may be much more likely.

Edited July 2, 2020 by MarcoSr
disease more likely

[sharkdoctor]

I suspect ulcerations of the shell are more likely. Likely of equal or greater scientific interest! See ulcerations in a modern turtle below

 

[Troodon]

Can a predator with a 45mm spacing be able to open its jaw wide enough to grasp the carpace to make those marks?  Croc unlikely. 

[MarcoSr]

6 hours ago, sharkdoctor said:

I suspect ulcerations of the shell are more likely. Likely of equal or greater scientific interest! See ulcerations in a modern turtle below

 

 

It really helps to see this picture.  This may be what I'm seeing.

 

Marco Sr.

[MarcoSr]

8 hours ago, Troodon said:

Can a predator with a 45mm spacing be able to open its jaw wide enough to grasp the carpace to make those marks?  Croc? 

 

That was the biggest problem that I have with the marks being puncture marks from a predator/scavenger.  This tortoise is 8 inches high at its highest point (I was originally told 9 inches by the prepper but I just measured it.)  That is a lot for a jaw to open that wide to try to grasp the tortoise unless it tried to grasp from the edge of the carapace.  This tortoise is just too heavy for me to try to roll it over to see if there are any corresponding marks on the plastron.  Members of the family Alligatoridae are found in the White River badlands.  However, we haven't found any Alligatoridae fossils on the M&M Ranch and I'm not aware of any being found before my sons purchased the ranch.  (Edit: I measured the tip spacing of the large fang pre-maxillary teeth in a 16 inch extant alligator skull and the tip spacing was 60mm) Maybe something like an Archaeotherium might be able to open that wide but I would expect a much larger canine tip spacing than 45mm .  Below is a skull of one that my son Marco Jr. found.  I'll ask him to measure the canine tip spacing and the distance between the upper and lower canine tips.

 

 

 

 

Marco Sr.

Edited July 2, 2020 by MarcoSr
added tip spacing comment, added alligator comment

[Peat Burns]

I found a late-cretaceous Baenid turtle (Hell Creek) that had similar marks.  I sent photos to a fossil turtle expert (academician).  He said he had found similar and also wondered if they were predation damage.  But he said after examining hundreds of modern turtle material in museum collections (and presumably other evidence), he concluded that the marks were bacterial infections.  

[MarcoSr]

20 minutes ago, Peat Burns said:

I found a late-cretaceous Baenid turtle (Hell Creek) that had similar marks.  I sent photos to a fossil turtle expert (academician).  He said he had found similar and also wondered if they were predation damage.  But he said after examining hundreds of modern turtle material in museum collections (and presumably other evidence), he concluded that the marks were bacterial infections.  

 

The more I think about this, the more I'm convinced that the holes were caused by disease.  It sure sounds better to say that your tortoise has predation marks but other than the fact of the same 45mm spacing pattern, disease seems much more likely to have caused the holes.

 

Marco Sr.

[caterpillar]

I've found the same marks on eocene turtles shells in France and it's a disease

[MarcoSr]

5 hours ago, caterpillar said:

I've found the same marks on eocene turtles shells in France and it's a disease

 

Disease is definitely the consensus.  I've seen turtles/tortoises on **** (we are not supposed to use sales website names here on TFF) that showed marks and claimed that they were predator puncture marks.  Because of this post, I now know that disease is probably the cause.  A carapace with predator puncture marks just sounds so much better than a diseased carapace.

 

Marco Sr.

[MarcoSr]

My son Marco Jr. took some canine tip spacing measurements from a few of the skulls (see picture) that he has from the M&M Ranch to see if anything was close to the 45mm spacing that I see in four hole sets in this tortoise.  I was really surprised by the results.

 

 

 

 

Using the Archaeotherium skull in the picture I posted above:  The upper canine spacing is 116mm and the distance between the bottom tip of the upper canines and the top tip of the lower canines was approximately 4".  So the spacing of the canines is much too wide and this pig might not have been able to get an 8" high shell into its mouth.

 

The saber tip spacing on two Hoplophoneus saber cat skulls that he had on hand were 36mm and 40.5 mm.  So smaller than 45mm but other genera of saber cats from the ranch are a little bigger.  But I can't see a saber cat trying to puncture a tortoise shell with its sabers.

 

Now for the really interesting measurements.  Measurements from 3 of the largest Oreodont skulls found on the ranch that my son had on hand to measure :  45mm, 45mm and 41mm.  Even though Oreodonts are herbivores they do have canine teeth.  Would a herbivore like an Oreodont have any reason to bite a tortoise shell?  Not that I can think of.  But what a coincidence that the tortoise has four sets of holes in the carapace with center spacing of 45mm, 45mm, 45mm, 44mm and my son has two Oreodont skulls on hand from the ranch with 45mm spacing between their canines.  Marco Jr. has found probably at least 25 or so Oreodont skulls from the ranch  (some were sold, some are at the prepper, some are in jackets) but only had three large skulls on hand to measure.  Or is this really only a coincidence?  Believe it or Not!!!!

 

Marco Sr.

[aplomado]

Lots of herbivores enjoy eating meat when they get the chance, including cows and horses.  There is no reason to think an oroedont wouldn't eat meat too.

[sharkdoctor]

40 minutes ago, MarcoSr said:

  But what a coincidence that the tortoise has four sets of holes in the carapace with center spacing of 45mm, 45mm, 45mm, 44mm and my son has two Oreodont skulls on hand from the ranch with 45mm spacing between their canines.  Marco Jr. has found probably at least 25 or so Oreodont skulls from the ranch  (some were sold, some are at the prepper, some are in jackets) but only had three large skulls on hand to measure.  Or is this really only a coincidence?  Believe it or Not!!!!

 

Marco Sr.

 

That's intriguing!! The next consideration might be to look at bite marks from similar tooth forms from other fauna. The alligator thread above was not convincing to me because their bite marks have a characteristic shape and often involve crushing (and displacement), whereas other predators involve tearing, etc. 

 

The other bit that may be useful to ponder is the shape of ulcerations vs bites. The lower hole in the second photo has a very unique shape. Would this more likely arise from a tooth under a fixed set of circumstances rather than from a bacterial ulceration?  

 

Another intriguing option is that shallow bites introduced bacteria to the shell and resulted in ulcerations!?!

 

-Aaron

[MarcoSr]

7 hours ago, sharkdoctor said:

 

That's intriguing!! The next consideration might be to look at bite marks from similar tooth forms from other fauna. The alligator thread above was not convincing to me because their bite marks have a characteristic shape and often involve crushing (and displacement), whereas other predators involve tearing, etc. 

 

The other bit that may be useful to ponder is the shape of ulcerations vs bites. The lower hole in the second photo has a very unique shape. Would this more likely arise from a tooth under a fixed set of circumstances rather than from a bacterial ulceration?  

 

Another intriguing option is that shallow bites introduced bacteria to the shell and resulted in ulcerations!?!

 

-Aaron

 

Aaron

 

At some point I may drag my tower and monitor over to the tortoise and use my digital microscope to take some close-up pictures of the holes.  In addition to close-up pictures showing the shapes of the holes themselves there could be some other tell tale signs like fine cracking emanating from the holes that I'm not seeing with the naked eye.  If I had a laptop I would have already taken these pictures.

 

Marco Sr.

 

[MarcoSr]

7 hours ago, aplomado said:

Lots of herbivores enjoy eating meat when they get the chance, including cows and horses.  There is no reason to think an oroedont wouldn't eat meat too.

 

That is interesting.  I didn't know that cows and horses would eat meat.  I'm not really sure how researchers determined that Oreodonts were herbivores.  I know teeth features help a lot.

 

Marco Sr.

[Randyw]

Ummmm.....this may be a dumb suggestion but have you considered Hyaenodon? I know there have been some larger specimens with a spacing between canines of around 41mm (sdsm 3017 for example)... and they could open their mouth wide enough to get a whole Dinictis skull in thier mouth...(reported in geo news July 2011 article titled “ tooth puncture marks on a 30 million year old dinictis skull”)

[jpc]

1 hour ago, MarcoSr said:

 

That is interesting.  I didn't know that cows and horses would eat meat.  I'm not really sure how researchers determined that Oreodonts were herbivores.  I know teeth features help a lot.

 

Marco Sr.

oreodont molars are veggiesaurus molars.  Carnivore teeth are very different.  I still think they are disease, but as Randy said, Hyaenodon might be worth a look.  

[MarcoSr]

1 hour ago, jpc said:

oreodont molars are veggiesaurus molars.  Carnivore teeth are very different.  I still think they are disease, but as Randy said, Hyaenodon might be worth a look.  

 

1 hour ago, Randyw said:

Ummmm.....this may be a dumb suggestion but have you considered Hyaenodon? I know there have been some larger specimens with a spacing between canines of around 41mm (sdsm 3017 for example)... and they could open their mouth wide enough to get a whole Dinictis skull in thier mouth...(reported in geo news July 2011 article titled “ tooth puncture marks on a 30 million year old dinictis skull”)

 

 

Marco Jr. thought that we should check out Hyaenodon.  That was the predator that he thought was the most likely one if the holes were teeth marks.  A fossil collector at one of the trips at the ranch last year found a pretty large Hyaenodon skull.  Marco Jr. was going to contact him to get a measurement between the canines.  The measurements for Hyaenodon in the geo news article at 35.4mm and 40.2mm are too small.  But other measurements in that article are smaller than what Marco Jr. measured on the specimens that he has especially the Archaeotherium in the article at 72mm (approx) when his skull had a spacing of 116 mm.  But you can see in the picture that I posted above, his Archaeotherium skull is quite large.

 

Marco Sr.

[MarcoSr]

2 hours ago, jpc said:

oreodont molars are veggiesaurus molars.  Carnivore teeth are very different.  I still think they are disease, but as Randy said, Hyaenodon might be worth a look.  

 

Jean-Pierre

 

Taking time to think about this, I really believe that this tortoise tried to take over an Oreodont burrow and the territorial Oreodont went postal on the intruder.     

 

Marco Sr.

[Randyw]

True. But I think they were using the hyeanadon horridus. The most common hyeanadon. The rarer  hyeanadon Gigas was even larger..
but I love the thought of an Oreodont going postal!

[MarcoSr]

11 hours ago, Randyw said:

True. But I think they were using the hyeanadon horridus. The most common hyeanadon. The rarer  hyeanadon Gigas was even larger..
but I love the thought of an Oreodont going postal!

 

According to Benton,Terry, Evanoff, McDonald 2015 The White River Badlands there are 3 Hyaenodon species (H. horridus, H. montanus, and H. crucians) in the White River with the body size of H. horridus being small compared to other species in the genus.  However I see elsewhere on the web that H. horridus was the largest North American Hyaenodon.  I also see on the web that H. gigas was the largest Hyaenodon species and was found in North America.  So needless to say I'm pretty confused by the contradictory information out there.   My tortoise came from the flats of the M&M Ranch which is Lower Scenic Member of the Oligocene Brule Formation.  I'm not sure which species of Hyaenodon are found in the Lower Scenic Member.

 

Marco Sr.

[aplomado]

18 hours ago, jpc said:

oreodont molars are veggiesaurus molars.  Carnivore teeth are very different.  I still think they are disease, but as Randy said, Hyaenodon might be worth a look.  

 

Oreodont molars look very similar to deer molars.  Of course, some deer like to eat meat on occasion (munjacs eat birds).

[doushantuo]

"Haynes, G. 1983. A guide for differentiating mammalian carnivore taxa
responsible for gnaw damage to herbivore limb bones. Paleobiology,
9:164–172." might possibly help?

BTW: the Miocene lignites of Ahnikov*(Czech Republic)  contains a hefty amount of gnawed bones,and some new ichnotaxa have been erectd for the traces

*diacritics omitted

 

Jaguar-Panthera-onca-predation-of-marine-turtles-conflict-between-flagship-species-in-Tortuguero-Costa-Rica.pdf

Predation on the tent tortoise Psammobates tentorius a whodunit with the honey badger Mellivora capensis as prime suspect.pdf

Kahlkee2015_BadgerpredationonpondturtleemianinterglaciPalaebiodivndPalaeoenvironments.pdf

[doushantuo]

dgfbull66-repturtcrocpredaMILAN211-218.pdf