My favorite has predation marks but what's the story?

[hunbun2]

Hi everyone. Iv'e been thinking about doing this for years and now, here I am! I have some interesting beach finds from "Sharks tooth island" and emerald isle, north carolina beaches. My favorite has obvious tooth marks. Black brown bone shard, about 1 inch long. Looks like something bit into the bone and cracked it open. There are a few molar marks and smaller tooth marks as well. The hole shown is I think a tendon insertion hole? So many predation marks on it. So cool! Any ideas of what the bone is and what had a good meal off of it?

[Fossildude19]

I'm not sure these are all predation marks.

They could be borings from piddock type clams.

[hunbun2]

Do they do that on bone? What I think of as "molar marks" are mechanically opposite of the fang like marks, as if something bit down and the bone snapped in an awkward section.  No serrated bite marks like are more common. Looks like a dog bit it!

[Fossildude19]

34 minutes ago, hunbun2 said:

Do they do that on bone?

 

 

Mineralized bone and rocks are both targeted by the piddock clams.

[Harry Pristis]

For illustration:

 

[ChristineR]

Predation marks always make me curious.  Are they predation or scavenger marks? Are there indications of who did the biting? I get especially curious when the bone is huge, with long marks preceding a break. The unknowns lead to many questions.  

 

I am sure there are many things that a predation mark can tell us. I just don’t know how to read them.  I believe it  was @MarcoSr who donated coprolites with feeding marks, to be studied.  Someone has likely studied every aspect of predation marks. 
 

 

[MarcoSr]

7 hours ago, ChristineR said:

 I believe it  was @MarcoSr who donated coprolites with feeding marks, to be studied.  Someone has likely studied every aspect of predation marks. 

 

 

 

After I noticed the marks on the tortoise carapace of the tortoise that I found on my sons' Eocene/Oligocene Ranch in Nebraska shown in the below pictures, I was convinced that they were teeth marks from a predator or scavenger.  There are 6 sets of 4 marks with identical mark spacing (1. 45mm 55mm, 2. 45mm 55mm, 3. 45mm 55mm, 4. 45mm 55mm, 5. 45mm 55mm, and 6. 44mm 55mm between hole centers) that I still believe are from a predator's/scavenger's canines.  One set of marks even had what looked like indentations from incisors (See the below pictures).  I searched the web for papers on predator/scavenger marks and was surprised by how few papers I found.  In addition, the papers were written by different authors.   I sent an e-mail with pictures to two authors of a paper on predation marks on a skull from the South Dakota badlands, but unfortunately I didn't receive a reply back.

 

I posted the below and additional pictures here on TFF and asked for opinions on the marks.  The overwhelming consensus was that the marks were from a shell disease that is common in turtles/tortoises.  So it is not likely that many, who respond to this post on the above specimen, will think that the above specimen does indeed have predation marks.  I actually definitely lean against predation marks, but I'm not totally convinced (Maybe crocodile????}.

 

Tortoise (23 inches X 17.5 inches X 8 inches) carapace with 6 sets of 4 marks circled in different colors:

 

 

 

 

Close-up picture of one set of 4 marks, with an additional indentation between two of the marks:

 

 

 

 

 

 

Marco Sr.

[digit]

I've run across only a few turtle shell fossils that definitely showed predation by alligator--though in most cases the bites look healed so the attacks were not fatal.

 

http://www.thefossilforum.com/index.php?/topic/111630-lucky-the-turtle/

 

Your rounded smooth markings are very characteristic of piddock clam borings. Anybody who has hunted for fossils in the Peace River in Florida has come across hundreds of fragments of dugong rib bone. They are solid with no spongy cancellous material inside so they fossilize extremely well. Piddock clams made burrows in a significant percentage of these dugong rib fragments (and in other types of fossils). I have probably seen tens of thousands of these borings over the years and your specimen was instantly recognized as having the same sort of borings.

 

https://www.google.com/search?q=pholad+boring&tbm=isch

 

 

Cheers.

 

-Ken

[Harry Pristis]

Predation marks:

 

 

[abyssunder]

The specimen in question reveals club-shaped pholad borings. One would ask: why, if it's bone?

The explenation would be that the osteic substrate is altered due to the mineralization process making it proper to be close to the lithic substrate, plus the specimen could be very dense, so pholads can react.

I have in my collection borings in amberground made by pholadids and when first seen that I was sure they are what is considered now to be very young (juvenile) Gastrochaenolites., although, at that time, they were considered something else.

Edited January 29, 2022 by abyssunder