3 more specimens - bones or rock?

[PSchleis]

Checking on three more specimens found on Myrtle Beach - I labeled them 4/5/6. I'm very curious about #6. The more I look at it, the more it doesn't look like a bone.

 

[digit]

Yup. Agreed that 4 and 5 have the look of worn bone but 6 is entirely different looking but I'd not exclude bone just yet. I'd like to see closer images of the smoother surface and the rougher side as well. Possibly taking some images in bright outdoor light (assuming it is sunny where you are) might yield a better view of this last one.

 

 

Cheers.

 

-Ken

[PSchleis]

5 hours ago, digit said:

Yup. Agreed that 4 and 5 have the look of worn bone but 6 is entirely different looking but I'd not exclude bone just yet. I'd like to see closer images of the smoother surface and the rougher side as well. Possibly taking some images in bright outdoor light (assuming it is sunny where you are) might yield a better view of this last one.

 

Ok more on No. 6 -- this is a really strange piece.

 

[PSchleis]

Ok I figured out No. 6. It's turtle

[digit]

I considered tortoise (a bit big for most turtles other than possibly a large snapping turtle). How did you come to this identification?

 

 

Cheers.

 

-Ken

[PSchleis]

11 hours ago, digit said:

How did you come to this identification?

I found this photo online, labeled "fossil turtle section from Montana."  

 

Mine has the same sandwich look:

 

Also, now that I had turtle as an option, I think I see it's shape. If you look at this photo, the part that is whitest (that half-curve at the bottom) is a very turtle-like indentation and curve before it gets to the ruffle at the edge. I just didn't see it because of the white coloring and heavy pitting on both sides of this piece. 

 

Of course, I also still think it looks like a fossilized pork chop.

 

(Oh - I'm using turtle and tortoise interchangeably because I couldn't begin to be able to identify the difference.)

 

[PSchleis]

Ok I'm doing some reading on tortoises and turtles. The turtle shell seems to be much smoother and more closely resembling my specimen. Unless erosion leveled out the top of this piece (and it sure could have) I'm thinking turtle.

[digit]

Turtles and tortoises both belong in the order Testudines (but in separate families). While folks may use the terms a bit interchangeably, I believe the distinction is that tortoises dwell on land and turtles may come up on land but generally live in water. Using my knowledge of Florida turtle/tortoise fossils as a guide for my opinions, all of the turtle shell finds tend to be from smaller freshwater turtles where the carapace (or plastron) thickness is generally under half an inch in thickness. We also find carapace fragments of a large tortoise (think Galapagos tortoise size) here in Florida that is generally assigned to the genus Hesperotestudo. Most of these finds are over an inch in thickness (as your find seems to be).

 

Other than possibly fragments of a sea turtle carapace (which I have no experience in), I generally think of the thinner pieces of carapace as turtle and the thicker pieces as tortoise. That is why I would suggest you pursue tortoise over turtle. Given the possible erosion of the surface on your item, I don't know that I'd be using surface texture as a particularly diagnostic clue.

 

And don't discount that fossilized pork chop if you happen to find some apple sauce preserved in amber nearby.

 

 

Cheers.

 

-Ken

[PSchleis]

Thanks for taking the time to explain all that. That being the case, tortoise does seem more likely given the size of this. The erosion is significant. Either way, fun to have found it! This is my first concerted effort to look for tortoise/turtle shell when I go beachcombing.

 

All the best -

Paula 

[Tidgy's Dad]

2 hours ago, digit said:

Turtles and tortoises both belong in the order Testudines (but in separate families). While folks may use the terms a bit interchangeably, I believe the distinction is that tortoises dwell on land and turtles may come up on land but generally live in water. 

Hmmmm. 

It's a lot more complicated than that. 

For example box turtles are exclusively terrestrial.

In the USA 'turtle' is often used as a general catch all for the whole group while in the UK and elsewhere tortoises are considered to be the land based ones and turtles the aquatic varieties. 

Technically they are all turtles - Order Testudines, but after that it gets a bit more complicated.

The superfamily Testudinoidea contains all the extant true land dwelling tortoises of the family Testudinidae. Tidgy is a representative, of course. 

But the superfamily also includes other families that include the box turtles and other groups that are very closely related some having entirely terrestrial lives and others amphibious or mostly aquatic. 

The fossil record gets even more complicated.

And please, don't ask about 'terrapins' . 

[Plax]

this could be marine turtle especially considering the provenance. Fossil tortoise frags have been found on beaches though.

[digit]

Thanks for the local intel.

 

 

Cheers.

 

-Ken

[Plax]

Most all the turtle shell I've found had the non porous portion preserved at the expense of the porous portion. This has a bone look to it but I'm not qualified to opine with any expertise. Since fossils at Myrtle Beach can be from the Cretaceous or Pliocene and Pleistocene it leaves a lot of possibilities. The adhering steinkern is from the Waccamaw or Canepatch I'd guess but an older clast could have been reworked into one of those formations. Also having little experience with tortoise bone in the fossil record it could be that I suppose.

  Am better with geology than fossils Ken!