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Turtles and Teeth-A few hunts in the Aquia


FossilsAnonymous

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FossilsAnonymous

We've had a couple nice hunts in the Aquia recently.

Our first trip was really nice. The weather was beautiful and the tide was low. The only finds of note from this trip were two shark vertebrae and a small yet pristine transitional otodus. As always, we found over a 100 teeth in the gentle shallows.

Our second trip was incredibly productive, albeit with fast moving water and a high tide on a beach ravaged by storms. We found what I think is a turtle washing out of a recent fall; I was unable to spot the rest of the turtle in the fall, however we were able to grab five pieces of material from the same spot,(within 6-7 feet of each other) and then find four more scattered along the beach. This trip was also very productive in terms of otodus, 3 in all from this same trip, although one was very badly damaged. Along with these larger beauties, innumerable teeth found their way into our hands and pockets.

Is there any way that the turtle can be identified? Is it possible to refer to this turtle material as from the same turtle? ( We weren't finding any the first trip and then found a ton the second trip)

@MarcoSr@sharkdoctor@WhodamanHD

Thanks, FA

IMG_8977.jpg.0423c27b527c0fa3ab7b42fe81b551f4.jpg

The rikers mount contains finds from both trips.

IMG_0687.jpg.b2f2b41b84a826ab0341ba6480f8f457.jpg

The largest fragment of turtle. Identifiable?

IMG_0688.jpg.a314faf960502029f2f95e28ced981e6.jpg

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Nice finds. :)

Love the turtle pieces though I can't help with an id.

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5 hours ago, FossilsAnonymous said:

The largest fragment of turtle. Identifiable?

IMG_0688.jpg.a314faf960502029f2f95e28ced981e6.jpg

                                  OLD!

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If you are finding the turtle shell in float it is less likely, but still possible, to be associated from a single turtle because there is lots of turtle shell at the site.  Typically Trionyx sp. (softshell turtle) is found.  The Trionyx carapace shell pieces have distinctive markings (see the four carapace Trionyx turtle shell pieces bottom left and center in the below display picture) and the plastron shell pieces are pretty nondescript (single plastron turtle shell piece bottom right in the below display picture).

 

 

5e49d36f9e082_PaleoceneAquiaFormationPotomacRiverLiverpoolPointMarylandspecimens8X121.thumb.JPG.1bc5f3a9fcfa8aa5ee7d5f92f1d5fba8.JPG

 

 

Marco Sr.

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FossilsAnonymous

@MarcoSr thank you. The plastron seems very similar to mine. 

I haven’t found anything from the carapace with those distinctive bumps, but it is still useful reference. Thank you.

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I think Marco Sr. got it, but if you ever have turtle material you want an expert to see in person, Dr. Weems tends to frequent to Maryland Geological Society meetings in Bowie every two months. He’s super nice and is always willing to lend a hand IDing things (especially reptilian material)

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12 hours ago, WhodamanHD said:

I think Marco Sr. got it, but if you ever have turtle material you want an expert to see in person, Dr. Weems tends to frequent to Maryland Geological Society meetings in Bowie every two months. He’s super nice and is always willing to lend a hand IDing things (especially reptilian material)

 

Dr. Weems is definitely the person to show your turtle shell to.  I may have been misleading with my earlier posts.  Trionyx are the more common turtle shell pieces found at the site.  However other Taxa can also be found.

 

Check out the paper "Weems 2014 Paleogene chelonians from Maryland and Virginia" at the below link:

 

 

https://escholarship.org/uc/item/7253p3tf

 

 

The abstract from this paper:

 

 

Fossil remains of 22 kinds of Paleogene turtles have been recovered in Maryland and Virginia from the early Paleocene Brightseat Formation (four taxa), late Paleocene Aquia Formation (nine taxa), early Eocene Nanjemoy Formation (five taxa), middle Eocene Piney Point Formation (one taxon), and mid-Oligocene Old Church Formation (three taxa). Twelve taxa are clearly marine forms, of which ten are pancheloniids (Ashleychelys palmeri, Carolinochelys wilsoni, Catapleura coatesi, Catapleura sp., Euclastes roundsi, E. wielandi, ?Lophochelys sp., Procolpochelys charlestonensis, Puppigerus camperi, and Tasbacka ruhoffi), and two are dermochelyids (Eosphargis insularis and cf. Eosphargis gigas). Eight taxa represent fluvial or terrestrial forms (Adocus sp., Judithemys kranzi n. sp., Planetochelys savoiei, cf. “Trionyx” halophilus, “Trionyx” pennatus, “Kinosternoid B,” Bothremydinae gen. et sp. indet., and Bothremydidae gen. et sp. indet.), and two taxa (Aspideretoides virginianus and Allaeochelys sp.) are trionychian turtles that probably frequented estuarine and nearshore marine environments. In Maryland and Virginia, turtle diversity superficially appears to decline throughout the Paleogene, but this probably is due to an upward bias in the local stratigraphic column toward more open marine environments that have preserved very few remains of riverine or terrestrial turtles.

 

 

EDIT:  The skull of Euclastes roundsi was found by my son Mel at that site and a cast is illustrated in the below figure from this paper:

 

 

image.thumb.png.d731ad98ac18589b3f28266e4c6da917.png

 

 

Marco Sr.

Edited by MarcoSr
Added skull found by Mel
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Another update to this post.  I actually learn a lot in trying to respond to some of these posts.  I have for over forty years thought that the turtle shell in my display was Trionyx based upon numerous publications.  However, looking at Dr. Weem's paper listed in an above reply, I noticed that he was not showing Trionyx in the Aquia (Piscataway).  So I sent him an e-mail asking if my specimens were Trionyx or Aspideretoides virginianus.  This is how he responded back:

 

 

"Trionyx is an African trionychid and as such is not known from North America.  As used in the 1800's, this name was more like a family name than a generic name.  The carapace in trionychids is much the same throughout the family, and the best differences are to be seen in the plastron and skull, neither of which tend to show up in our deposits.  If you noticed, in my paper I had "Trionyx" halophilus because the generic name Trionyx was used in the initial description, it is not appropriate, but no proper name can be yet proposed for lack of skull or plastron data.  So none of this material is truly Trionyx.

 

Probably the best way to distinguish Aspideretoides virginianus from "Trionyx" halophilus is by the relative thickness of the shell; halophilus is much thinner than virginianus at a comparable size.  The big difference in pattern is that halophilus has more discretely rounded pits, rather like in croc armor, whereas virginianus pits tend to run together laterally into strings that have only low ridges between them but much higher ridges between the strings of pits.  I would say that what you have looks more like virginianus to me."

 

 

So the turtle shell in my display is not Trionyx but Aspideretoides virginianus.  So it is Aspideretoides virginianus that is fairly common from this site.  Note you will see Trionyx listed in many places on the web and that is incorrect for the Aquia (Piscataway) based upon Dr. Weems.

 

Marco Sr.

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33 minutes ago, MarcoSr said:

Trionyx is an African trionychid and as such is not known from North America. 

That’s news to me, good to know.

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