Pocket Gopher Femur, SD

[PaleoNoel]

Hi everyone, I was just browsing @PrehistoricFlorida's website and my eye was caught by what was labelled as a pocket gopher femur (trust me there were many more impressive fossils that caught my eye as well). Reason being, I found a very similar bone on a hunt in South Dakota's Hell Creek formation back in 2019. I kept it, hoping in my heart of hearts that it was fossilized, but keeping my expectations low. The rusty staining on the bone made me think there was a chance it was just a beautifully preserved Cretaceous limb bone, but I knew it was most likely recent. It's about 2.5 cm long and .7 cm wide at the proximal end. 

I'm interested in your opinions about whether or not I can confirm this bone as modern/recent.

Floridian specimen.

Dakotan specimen.

[Bobby Rico]

You can try a burn test to determine if it is a fossil or recent.

Hold a flame to a part of the bone. If it gives off a smell of burnt hair, it is likely recent. 

If it doesn't burn or give off an odor, it is more likely  a fossil. 

Edited January 3, 2022 by Bobby Rico

[jpc]

looks fossily from here, esp on the last photo.  Very nice find.  Rodents were a long way from evolving by Hell Creek time, so it would not be a rodent.  Postcranials of Lancian mammals (and this IS a mammal femur) are not well known.  you might want to hunt down some papers on Cret mammals from Mongolia and Paleocene multituberculates.  There are some very well preserved mammals from Mongolia.  

[ClearLake]

To me it looks very much like a ground squirrel femur (and probably recent) rather than a pocket gopher.  Here is a snapshot out of Gilberts "Mammalian Osteology" which shows a Spermophilus columbianus which matches quite closely.  I believe that is no longer the proper genus name, but you can start form there.  It could also be one of the other species, not sure what is native to where you found it.

 

[siteseer]

I don't think you can hope to find a Cretaceous mammal femur in that condition from Hell Creek.  Paleontologists specializing in those animals are deliriously happy to find just bone ends in their screenings.  Only the hardest parts tend to survive as fossils in the Hell Creek like gar scales, dermal denticles, and teeth because anything more delicate like the shaft of a limb bone would have been snapped and ground into micro-bits by water action in the river.

 

Partial skeletons are found in Mongolia.

[jpc]

and hope we do.  : )

but I have to agree that such a complete bone from a Cret mammal would be a truly rare find.  I just did a google search for cretaceous mammal skeletons and found no good pictures of a femur.    

Edited January 4, 2022 by jpc

[Plax]

17 hours ago, ClearLake said:

To me it looks very much like a ground squirrel femur (and probably recent) rather than a pocket gopher.  Here is a snapshot out of Gilberts "Mammalian Osteology" which shows a Spermophilus columbianus which matches quite closely.  I believe that is no longer the proper genus name, but you can start form there.  It could also be one of the other species, not sure what is native to where you found it.

 

Wish the book wasn't 200 bucks. Looks to be a fantastic reference.

[ClearLake]

27 minutes ago, Plax said:

Wish the book wasn't 200 bucks. Looks to be a fantastic reference.

Wow!  I thought you were exaggerating when I first read that, but then I went and looked and it is true.  It is a very good reference butI know I did not pay anywhere near that price.  However, that was quite some time ago.  I guess I should be more careful with my copy!  

[PaleoNoel]

On 1/3/2022 at 2:59 PM, Bobby Rico said:

You can try a burn test to determine if it is a fossil or recent.

Hold a flame to a part of the bone. If it gives off a smell of burnt hair, it is likely recent. 

If it doesn't burn or give off an odor, it is more likely  a fossil. 

Ok, I might give it a try.

23 hours ago, jpc said:

looks fossily from here, esp on the last photo.  Very nice find.  Rodents were a long way from evolving by Hell Creek time, so it would not be a rodent.  Postcranials of Lancian mammals (and this IS a mammal femur) are not well known.  you might want to hunt down some papers on Cret mammals from Mongolia and Paleocene multituberculates.  There are some very well preserved mammals from Mongolia.  

Thanks JP, when I saw the similarity to an extant rodent my mind immediately went to modern as I'm aware they weren't yet around at the end of the Cretaceous. After searching for images of multi femurs, it appears to definitely be rodent.

22 hours ago, ClearLake said:

To me it looks very much like a ground squirrel femur (and probably recent) rather than a pocket gopher.  Here is a snapshot out of Gilberts "Mammalian Osteology" which shows a Spermophilus columbianus which matches quite closely.  I believe that is no longer the proper genus name, but you can start form there.  It could also be one of the other species, not sure what is native to where you found it.

 

It could very well be ground squirrel as they're in SD, as are pocket gophers, prairie dogs and other mid size rodents that could fit the bill.

18 hours ago, siteseer said:

I don't think you can hope to find a Cretaceous mammal femur in that condition from Hell Creek.  Paleontologists specializing in those animals are deliriously happy to find just bone ends in their screenings.  Only the hardest parts tend to survive as fossils in the Hell Creek like gar scales, dermal denticles, and teeth because anything more delicate like the shaft of a limb bone would have been snapped and ground into micro-bits by water action in the river.

Partial skeletons are found in Mongolia.

That's been my experience for the most part, although I've found a few complete small limbs, along with some very delicate bird/small nonavian theropod bones at microsites and channel deposits, although these tend to be incomplete.