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Turtle carapace fragment or Glyptodon? Psephophorus


Plantguy

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Hey Gang, 

 

I acquired this fragment as I was extremely intrigued with the pattern as it was described as Glyptodont.

1369950084_PossibleseaturtlecarapacefragmentMarionCounty.thumb.jpg.acf173fedc2c152a9a53d5104f94a3c1.jpg
 
1764077362_Possibleseaturtle3Marioncounty.thumb.jpg.162859480ac4b6c7e5bcb1051fdd7958.jpg
I've been still playing around with turtle fragments oh way too much lately and my brain is saying this is not Glyptodont and wants to say the textures and groove pattern and polygonal nature are perhaps an ossicle or maybe ossicles from something like Psephophorus polygonus. Are the surface grooves sulci? Its not completely flat on the bottom has a general irregular arch to it and varies in thickness from 1 to 1.8 cms..

Does anyone have any similar pieces and/or agree or disagree? I have been going thru pubs and photos and I'm not convinced that I know what I'm talking about...wont be the first or last time! 

 

I havent run it past the UF folks yet but intend to do so...

Thanks! 

Regards, Chris 

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Weathered turtle plastron piece comes to my mind, looking at the third picture, but I'm unsure. 

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pachy-pleuro-whatnot-odon

Glyptodont was actually the first thing that came to my mind when I hadn't read the text yet, although I have zero experience with either glyptodont osteoderms/armour nor turtle plastrons. I do agree, however, that the pattern on top of the specimen seems too irregular for the glyptodont I'm familiar with. All the same, the piece has the right thickness. Could such a deviating pattern as we're seeing here have been caused by placement of the scute in life, or a pathology? In any case, may be @Harry Pristis can help...

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Harry Pristis

Glyptothere came to my mind, but it's a struggle to make that fit.  But, I can't even pronounce "Psephophorus" much less identify it.  @Boesse has published on this turtle.

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@caterpillar, @abyssunder, @pachy-pleuro-whatnot-odon, @Harry Pristis

Thanks all for your thoughts/feedback! Its nice to have multiple sets of eyes/backgrounds review a find and more intriguing when there isnt a consensus.

 

I've been doing more digging tonight and had seen Bobby's Purisima Fm. find/article and actually quite a few other articles...

Here's the one I stumbled on initially:

 

First record of a leatherback sea turtle (Dermochelyidae) from the Mio-Pliocene
Purisima Formation of northern California, USA BAILEY R. FALLON1* and ROBERT W. BOESSENECKER. PaleoBios 36:1–8, June 25, 2019

 

but after Harry you mentioned him I dug further and also ran across his Oligocene South Carolina article/discussion....

 

Fallon, B.R. and Boessenecker, R.W. 2020. Multispecies leatherback turtle assemblage from the Oligocene Chandler Bridge and Ashley formations of South Carolina, USA. Acta Palaeontologica Polonica 65 (4): 763–776.

 

Here's a crazy photo showing articulated Psephophorus polygonus ossicles from one specimen in 

Cainozoic Research, 19(2), pp. 121-133, December 2019 121 

A Miocene leatherback turtle from the Westerschelde (The Netherlands) with possible cetacean bite marks: identification, taphonomy and cladistics Marit E. Peters1 , Mark E.J. Bosselaers2 , Klaas Post3 & Jelle W.F. Reumer

From Page 127

722676303_PsephophoruspolygonusWesterscheldetheNetherlands.jpg.eccc895714178b47de61c2e432162bdc.jpg

 

 

Its late and I'm out of reading time so maybe he'll be able to checkin/comment and provide his expertise and give a thumbs up or thumbs down. 

Thanks again! 

Regards, Chris 

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Shellseeker

Gorgeous stuff,  Chris.  It is always exciting to be discovering something new.  Ride that wave!!!! New fossils are especially exciting when the water is cresting 3-4 feet over my head.  :thumbsu:

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pachy-pleuro-whatnot-odon

Miocene leatherback turtles from the Westerschelde! That's pretty exciting stuff for me as a dutchman...! I never knew we had those! But... I now do see some similarity there as well. Interesting to see how this develops :popcorn:

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hemipristis
12 hours ago, abyssunder said:

Weathered turtle plastron piece comes to my mind, looking at the third picture, but I'm unsure. 

Looked turtle-y to me as well, but there was something about the texture I couldn't;t put my finger on.  

 

If leatherback, congratulations!

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Hey Gang,

@caterpillar @abyssunder @pachy-pleuro-whatnot-odon @Harry Pristis @Shellseeker @hemipristis

An update...so it looks like I was right that its not glyptodon as was labeled, but unfortunately wrong about it being marine turtle.

 

Sounds like its more probably a supernumerary bone of a giant tortoise, probably around the suprapygals toward the back of the carapace.

Those polygonal grooves/lines are extra scute sulci as well which isn’t too uncommon.

 

So I've got lots more to go investigate/learn/read about! 

Thanks again for all the comments/feedback/encouragement!! 

 

Continued hunting success! 

Regards, Chris 

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Shellseeker

Thanks Chris for the follow_up. It is always good news to get to a right answer. The process of discovery is its own reward.  Jack

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22 hours ago, Shellseeker said:

Thanks Chris for the follow_up. It is always good news to get to a right answer. The process of discovery is its own reward.  Jack

Hey Jack, yes the process is invigorating and has as many undiscovered holes as the Peace River and surrounding areas do. 

 

This particular find of another giant tortoise fragment adds to my current wonderment about our turtle/tortoise scraps.  With alot of help I've been able to identify fragments of Pseudemys, Trachemys, Terrapene, Kinosternon, Gopherus, Chelydra, and Hesperotestudo here locally.

 

One of my favorite thus far and not very impressive at all (and coming in at a whopping under 2 cm) is a juvenile tortoise carapace fragment--

Hesperotestudo from the Bowling Green mine showing growth annuli. 

935365463_JuvenileHesperotestudofragmentBowlingGreen.thumb.jpg.c9c7e946cfdc56751870aef097636b56.jpg

It didnt take too much to get me intrigued about this little critter fragment and how it met its untimely demise and ended up where I found it!

The search/quest continues...

 

Regards, Chris  

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This element is certainly turtle - the radial channels and flaky-ness of the bone on the internal surface look right - but the irregular shape is wrong for leatherback: leatherback ossicles typically have polygonal flat-sided edges rather than weird triangular apices, and none of the named leatherbacks have this weird channel texture.

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5 minutes ago, Boesse said:

This element is certainly turtle - the radial channels and flaky-ness of the bone on the internal surface look right - but the irregular shape is wrong for leatherback: leatherback ossicles typically have polygonal flat-sided edges rather than weird triangular apices, and none of the named leatherbacks have this weird channel texture.

Thanks Bobby. I appreciate you looking and providing additional feedback/details. 

 

Regards, Chris 

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Shellseeker

I am currently tracking this one....

http://www.thefossilforum.com/index.php?/topic/116599-an-interesting-bone/&tab=comments#comment-1283140

 

Not a lot of response on the thread but there are a couple of other threads discussing Cannon bones with their associated metatarsals and metacarpals.

Too small to be Equus, I believe it is a right 3rd metatarsal (cannon bone) of a pre_equus horse.  I still want to know which one.

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turtlesteve

Normally the channels would correspond to scute sutures.  
 

Just a guess, but might be pathology, tortoises that survive fires can end up with weird random scute sutures, or even none at all.

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5 hours ago, turtlesteve said:

Normally the channels would correspond to scute sutures.  
 

Just a guess, but might be pathology, tortoises that survive fires can end up with weird random scute sutures, or even none at all.

Thanks Steve, yep this one is a bit different! 

Regards, Chris 

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