Dugong rib Predator markings?

[PODIGGER]

Was out on the Peace River yesterday and found two Dugong rib bones larger than what I normally come across so I decided to keep them.  These dugong bones are so numerous I don't usually save them to add to my collection.  After cleaning the bones with some mild soap and water I found one of them to have what look like slice or cut marks on one side.  I found this very strange and wanted to ask if anyone has come across similar markings and what may have caused them.  Any of the Florida/Peace River crew have an idea?  @Harry Pristis @Shellseeker @Bone Daddy

 

         

 

 

    

 

[Harry Pristis]

This is not a rare phenomenon with dugongid ribs.  Most common is shark tooth drag marks as the predators/scavengers strip meat from bone.

[PODIGGER]

Thanks Harry! I guess all the previous ones I have found were just to small and beat up for me to notice similar marks.

[Shellseeker]

5 hours ago, Harry Pristis said:

This is not a rare phenomenon with dugongid ribs.  Most common is shark tooth drag marks as the predators/scavengers strip meat from bone.

 

As Harry indicates, these are not rare.  Plenty of dugongid ribs are lacking these marks,  but there are lots of ribs,and 5-10% have bite marks.

Harry, I have often wondered if I can "guess" at the size of the predator by the gap between the scars (which might be the gap between the teeth).

Make it general... Is there any info that one can obtain from teeth marks on fossil bone?

 

[PODIGGER]

Jack, Thanks for your response and interesting question.  I am eager to see what Harry’s answer may be.

[Bone Daddy]

Nice find. Dugong ribs are often underwhelming (there are so many!), but finding one with predation marks is always a keeper. I've found a few like this, including one with very deep gouges. 

[PODIGGER]

Thanks for the input. I’m heading back tomorrow to the same spot to see what else turns up. Found several partial megs a nice hemi and two complete dolphin periotic bones there on the last visit.

[Harry Pristis]

17 hours ago, PODIGGER said:

Jack, Thanks for your response and interesting question.  I am eager to see what Harry’s answer may be.

 

I don't think there's an answer to Jack's question because there are different sharks and different sizes of the same shark to consider.  Generally, I suppose the deeper and wider apart the tooth marks, the larger the shark.

[PODIGGER]

Thanks for your response Harry!

[Shellseeker]

9 hours ago, Harry Pristis said:

 

I don't think there's an answer to Jack's question because there are different sharks and different sizes of the same shark to consider.  Generally, I suppose the deeper and wider apart the tooth marks, the larger the shark.

 

Thanks for the response, Harry.  Most times on dugong ribs, I see the long parallel lines that would indicate "shark" versus mammal.  On @PODIGGER's teeth, there are narrower gaps and most likely multiple bites from a sequence of predators.

Occasionally, I have seen a dugong rib with 3 or 4 long gouges more than 2 inches apart and wondered about the size of the shark that left the marks.  Did it have to be Megalodon or would Snaggletooth do?

I have also wondered what the marks left by a Dire wolf or Jaguar would look like. There are a whole lot of questions and so few answers.