Limb Bone From The Chesapeake Bay

[SouthernMdRan]

I have a post in the Fossi Hunting Trips area about this, but wanted to specifically make a post here.

Attached are pictures of what appears to be a mammal bone that I found washed up at a beach on the western shore of the Chesapeake Bay yesterday as I searched primarily for shark teeth there.

I presume it's something like a leg bone of some mammal...and I presume that it is a fossil (rather than a 'modern' bone).

Any ideas what this could be from?

I appreciate the help.

Thanks.

[squalicorax]

Here is some info on your find http://www.thefossilforum.com/index.php/topic/22234-bison-versus-cow-metatarsal-morphology/

[jpc]

I see fused metatarsals of one of the modern artiodactyls... cow is my guess, but there are others here who are better at modern bones.

[RichW9090]

Looks like a metacarpal, perhaps Bison/Bos. There is a bit of Pleistocene overlying the Miocene along most of the Chesapeake Bay, and it has produced a few fossils, so it could be either. It is pretty narrow, so more likely Bos, I'd think. It is a metacarpal because the groove on the anterior surface of the bone extends only part way down the shaft. The metatarsal has the groove almost the entire length of the shaft. Also, the proximal end is diagnostically different, but the photo is at an angle and not very clear - while it looks like a metacarpal, I can't say for sure from the photograph, based just on the end of the bone. But the identification as a metacarpal is clear - the groove gives it away.

[Auspex]

...It is a metacarpal because the groove on the anterior surface of the bone extends only part way down the shaft. The metatarsal has the groove almost the entire length of the shaft...

Good stuff; thanks for the details!