Small Complete Bone--Astragalus? Phalanx?

[Brandy Cole]

Had a great day of fossil hunting this weekend with @Lorne Ledger.  Got everything washed up, and now it's time to try to identify!

 

I found this smaller, fairly complete bone in Southeast Texas.  Mostly Pleistocene fossils here.

 

It's confusing to me because one face reminds me of a deer astragalus, but a few other features don't quite seem to match.   Since it seems to have several attachment points I considered it might also be a phalanx from something.  

 

Any ideas would be welcome to point me in the right direction.

 

Thanks,

Brandy

 

 

@Lorne Ledger @Harry Pristis @JohnJ @garyc

[Harry Pristis]

I think this is a "radial carpal" (scaphoid) from a cow.

 

 

 

[Brandy Cole]

23 minutes ago, Harry Pristis said:

I think this is a "radial carpal" (scaphoid) from a cow.

 

 

 

 

Thank you for taking a look! It is fully mineralized. 

Could a specimen from a cow be old enough to be mineralized? 

[garyc]

Cool little bone! I would have guessed carpal as well, but must defer to Harry for species and position. You’re killing it on the river!!!

[Harry Pristis]

2 hours ago, Brandy Cole said:

 

Thank you for taking a look! It is fully mineralized. 

Could a specimen from a cow be old enough to be mineralized? 

 

Maybe . . . I don't know that river.  You decide what it is; if it's cow, we'll know that mineralization of cow bones is possible.  Did you try the flame/scorch test on the bone?

[Brandy Cole]

19 hours ago, Harry Pristis said:

 

Maybe . . . I don't know that river.  You decide what it is; if it's cow, we'll know that mineralization of cow bones is possible.  Did you try the flame/scorch test on the bone?

 

 

I tested it this morning, and it had no reaction to flame.  It's heavy for its size, solid, and it's the dark reddish brown color that's consistent with most of the other mineralized fossils I find here.  It makes the 'ting' sound associated with rock when I strike it with metal rather than the more wooden/hollow type sound of modern bone.  

 

I compared it to the example diagrams you've posted, and I do see the areas that appear to more closely resemble bos rather than bison.  I also see a few features on this bone that don't seem to be depicted in the examples.  Do you have any other reference pictures or books that you could recommend for me to review?  There are a few edges on this one that look to be rounded off, and that might be making it harder for me to compare accurately. 

 

I had assumed, and maybe incorrectly, that any bos bones I found would by necessity be modern bos taurus and un-mineralized, since modern cows weren't introduced here until a few hundred years ago, and I thought it took much longer to mineralize than that.  But I'm sure others with more experience in this area would know better.

 

What I've most commonly found in this part of the river are mineralized materials from equus, camelid, and tortoise specimens.  And I occasionally, but less commonly, find mammoth/mastodon material.  Also less commonly, I find modern cow and deer bones that are clearly not mineralized.

 

@garyc Thank you!  After the river finally receded, it left a lot of great stuff behind.  The most exciting finds for me so far were the mastodon tusk fragment, a mammoth metacarpal and phalanx, and the glyptodont vertebra.  The glyptodont vertebra was mostly buried and a lighter color than most of what I find, and I almost walked right over it, assuming it was a modern bone!  I'm going to try to hunt as much as I can now while the weather is nice and before the river levels rise again.  We all know it's always just a matter of time before the next downpour changes things. 

 

--Brandy

 

[Harry Pristis]

(7) The lateral extension of the articular surface for the radius approximates a right angle in Bos. In Bison it forms part of a continuous gentle curve from the dorsal apex.

 

 

 

[Brandy Cole]

On 9/28/2021 at 8:49 PM, Harry Pristis said:

(7) The lateral extension of the articular surface for the radius approximates a right angle in Bos. In Bison it forms part of a continuous gentle curve from the dorsal apex.

 

 

 

Thank you so much for the examples!

 

I'm still working on learning the anatomy and how everything fits together, so I'm not sure exactly how I should orient the bone to compare it to this example.

 

I'm posting additional views in case that helps.

 

Is the articular surface I should be looking at one of the smooth, flat sides from the first two pictures below?  If so, which should I be looking at, and which way should I hold it to get a comparable view?

 

Or would the 'short' sides in the bottom two pictures also be articular surfaces?

 

Thank you again for the help,

Brandy

 

[Harry Pristis]

If you can't find faces of your bone to match the line drawings, maybe it's not a scaphoid after all.  There are other, not dissimilar, ankle bones.  Try searching for "cow ankle bones."

 

Here are the homologs from horse and camel:

 

 

 

 

[Brandy Cole]

@Harry Pristis

I was able to take this piece with me to the Vertebrate Paleontology Lab at University of Texas along with a few other unidentified fossils.  The lab manager, Kenny Bader, excluded cow and bison, but we weren't able to get a definitive ID in the time we had.  I do think scaphoid or a homolog is the right direction.

 

I didn't ask him if we could check camelid, but now that I've had a chance to figure out how to orient this better in comparison to the examples in your last post, it does seem to bear  resemblance to camelid.

 

Thank you for all your many examples online.  They've been a tremendous learning tool for me.