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Hell Creek Fish / Reptile? (UPDATED: Pics)


Peat Burns

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Hi All,

 

I am hoping someone might recognize this bone fragment.  It is from the Hell Creek Formation (Late-Cretaceous) of South Dakota.  It looks fishy to me but does not have the exterior texture of gar skull.  The exterior is really "pocked", almost like small, conchoidal chips.  If fish, maybe bowfin, paddlefish, or sturgeon skull fragment?  Only other thought I had was maybe crocodilian or champsosaur skull fragment, but I am leaning fish.  There might be enough structure on the interior surface for someone to recognize which bone.  Top photo is the exterior surface, middle is interior surface, and bottom photo is close-up (under magnification) of the exterior surface.  Scale is in cm / mm.  Thanks for any help.

FishReptileQuestion.thumb.jpg.c6276c04945fdc309189221af7b54f22.jpg

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@Peat Burns, could you post some closeups?

 

EDIT: images that can be individually viewed at full size.

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"I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?"  ~Aldo Leopold (1887-1948) 

 

New Mexico Museum of Natural History Bulletins    

 

point.thumb.jpg.e8c20b9cd1882c9813380ade830e1f32.jpg research.jpg.932a4c776c9696d3cf6133084c2d9a84.jpg  RPV.jpg.d17a6f3deca931bfdce34e2a5f29511d.jpg  SJB.jpg.f032e0b315b0e335acf103408a762803.jpg  butterfly.jpg.71c7cc456dfbbae76f15995f00b221ff.jpg  Htoad.jpg.3d40423ae4f226cfcc7e0aba3b331565.jpg  library.jpg.56c23fbd183a19af79384c4b8c431757.jpg  OIP.jpg.163d5efffd320f70f956e9a53f9cd7db.jpg

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17 minutes ago, PFOOLEY said:

How thick is the specimen?...leaning towards turtle.

It's about 3-4 mm thick (sorry, I should have included that)

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39 minutes ago, PFOOLEY said:

@Peat Burns, could you post some closeups?

 

EDIT: images that can be individually viewed at full size.

I'll post some better close-ups tonight, including side-view (I'm away from my work area at the moment). 

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12 minutes ago, jpc said:

as long as you are going to post a few more pix, can we see a photo of the broken edge.  

Yes.  It will be helpful, I think.  It tapers off to a thin edge rather than being a 90 degree fracture typical of most of the turtle shells I find.  I should be able to post something by 9 pm EST.  

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@Al Dente, @jpc, @PFOOLEY, @Troodon, et al.  This may take several replies.  These two pics are photos of the edge of the fossil (see caption on photos for details)

SectionThroughUnknown1.thumb.jpg.e2d774afa8231b478684f23784300cb0.jpg

SectionThroughUnknown2.thumb.jpg.eb402740fef8e0b181a500a2c41f62ef.jpg

 

The pic below is a close-up of the "pocked" dorsal surface texture (i.e. not a regular pattern as in typical turtle shell)

FishQuestion1.thumb.jpg.ce2cdb638c82a3db7bb0b86da15bd8ec.jpg

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@Al Dente, @jpc, @PFOOLEY, @Troodon, et al.  This shows the fossil in question (left) next to a Hell Creek turtle pleural and neural in both oblique and ventral views (see notes on photo)

TurtleComparisonComposite.thumb.jpg.2d3bcf3131293f14351017af24ade807.jpg

 

This photo shows the edge of a Hell Creek turtle pleural of similar thickness to the fossil in question (above) and a Hell Creek turtle Neural below.

 

TurtleComparisonComposite2.thumb.jpg.fa6f6f5427d42cce1ac57346644c7e9a.jpg

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I will stick with turtle. I believe it is the weathering of the piece that is creating the unusual features. 

  • I found this Informative 1

"I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?"  ~Aldo Leopold (1887-1948) 

 

New Mexico Museum of Natural History Bulletins    

 

point.thumb.jpg.e8c20b9cd1882c9813380ade830e1f32.jpg research.jpg.932a4c776c9696d3cf6133084c2d9a84.jpg  RPV.jpg.d17a6f3deca931bfdce34e2a5f29511d.jpg  SJB.jpg.f032e0b315b0e335acf103408a762803.jpg  butterfly.jpg.71c7cc456dfbbae76f15995f00b221ff.jpg  Htoad.jpg.3d40423ae4f226cfcc7e0aba3b331565.jpg  library.jpg.56c23fbd183a19af79384c4b8c431757.jpg  OIP.jpg.163d5efffd320f70f956e9a53f9cd7db.jpg

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Just now, PFOOLEY said:

I will stick with turtle. I believe it is the weathering of the piece that is creating the unusual features. 

Thanks very much.  Do you think the depression / concavity is where the spinal encasement eroded away (i.e. a neural)?

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turtle.  Remember, there are many types of turtles in the Hell Creek and each turtle has many different neural bones,and they come in thicknesses.  

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5 minutes ago, Peat Burns said:

Thanks very much...

 

You are welcome.

 

5 minutes ago, Peat Burns said:

...Do you think the depression / concavity is where the spinal encasement eroded away (i.e. a neural)?

 

Yes.

  • I found this Informative 1

"I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?"  ~Aldo Leopold (1887-1948) 

 

New Mexico Museum of Natural History Bulletins    

 

point.thumb.jpg.e8c20b9cd1882c9813380ade830e1f32.jpg research.jpg.932a4c776c9696d3cf6133084c2d9a84.jpg  RPV.jpg.d17a6f3deca931bfdce34e2a5f29511d.jpg  SJB.jpg.f032e0b315b0e335acf103408a762803.jpg  butterfly.jpg.71c7cc456dfbbae76f15995f00b221ff.jpg  Htoad.jpg.3d40423ae4f226cfcc7e0aba3b331565.jpg  library.jpg.56c23fbd183a19af79384c4b8c431757.jpg  OIP.jpg.163d5efffd320f70f956e9a53f9cd7db.jpg

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One more onto the turtle bandwagon. This isn't really a good match for sturgeon. Sturgeon bone ornamentation (regardless of the genus...) pretty much resembles this: respro_happisburgh_fossils3_624x464.jpg

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