Epiphysis?

[Brandy Cole]

I scrubbed as hard as I dared to try to remove the light brown particulate on this to make the articular surfaces clearer, but not much luck.

 

I'll give it a shot as is.  Not sure exactly what I found.  I actually passed it up twice thinking it was chert until I got a closer look and saw osteoporosity along one edge.

 

My best guess is epiphysis, but I'm not sure what from.

[Mahnmut]

hello Brandy Cole,

Epiphysis could be,

I could also imagine this to be some kind of metapodial.

Best Regards,

J

 

[Harry Pristis]

 

The light color crust is distracting to the eye . . . If it's limestone, give it a bath in white vinegar.  Vinegar shouldn't affect the mineralized bone.

Your find may be a bovid cubonavicular.  Compare to:

 

[pachy-pleuro-whatnot-odon]

47 minutes ago, Harry Pristis said:

The light color crust is distracting to the eye . . . If it's limestone, give it a bath in white vinegar.  Vinegar shouldn't affect the mineralized bone.

 

Since there's visible vascularisation and thus incomplete mineralisation, I'd be careful with putting this in vinegar. Without a full cortical covering, you'd get quite high penetration of the acid into the inner structure of the bone with uncertain results. Moreover, the accord would be difficult to properly wash out, leaving any leftovers to work on the bone over a long period of time.

 

Rather I suggest trying to carefully scrape the matrix of with a toothpick, or apply acid using a soaked cotton wad or piece of textile, properly rinsing with water afterwards. Dipping a toothbrush in vinegar and brushing the matrix on the bone with that may also prove very effective...

[Harry Pristis]

3 minutes ago, pachy-pleuro-whatnot-odon said:

Since there's visible vascularisation and thus incomplete mineralisation, . . .

It's appropriate to question my apparent assumption that the bone is mineralized; I meant to make mineralized a condition for a vinegar bath, but didn't express myself very clearly.  Even so, vinegar doesn't pose a great threat to bovid bone.

 

What is it you are trying to say in concluding the bone is NOT mineralized?  Vascularization is not obliterated or filled-in by permineralization.  Even bones entirely replaced by exogenous minerals may preserve nerve and blood vessel foramina.  Replacement is not the common condition of Pleistocene bones in Texas or in Florida.  Even my few French vertebrate fossils from the Eocene are thoroughly mineralized (?replaced), yet show their foramina normally.

 

[fossilus]

2 hours ago, Brandy Cole said:

I scrubbed as hard as I dared to try to remove the light brown particulate on this to make the articular surfaces clearer, but not much luck.

 

 

 

I've had decent luck removing this stuff if I catch it when it's still wet with bleach water and a toothbrush. Once it dries it's almost impossible to remove. 

I think it's from algae as it's worst when found on a fossil in a few inches of water or less. (photic zone)

 

 

 

[Brandy Cole]

Thank you @Harry Pristis Cubonavicular looks like a good match. I'll be able to compare it better when I have it in hand at home.

 

@pachy-pleuro-whatnot-odon

For what it's worth, it looks and feels  thoroughly mineralized.

 

My only fear in rubbing too hard was that even in thoroughly mineralized pieces, I can sometimes scrub out little flakes in the small porous places where the river tumbling has already worn through the cortical bone.  So I would probably prefer a soak rather than more abrasive options.

 

I've used a water and vinegar solution on similarly mineralized pieces before with no ill effects on the piece except for occasional  lightening of the natural color once it dries.  I feel pretty comfortable trying it on this one at home later.

 

@fossilus

Yes, it was in an inch or so of water.  Here's hoping it's limestone, since algae is so frustratingly stubborn to remove!  This one has already completely dried.

 

I haven't tried using bleach right away when I bring a damp piece home yet.  Thanks for the tip. In the future, I'll give it a shot.

[GPayton]

@Brandy Cole I know exactly how much of a pain it is to get that algae off. Aside from scrubbing with an old tootbrush and soap, I've found that the easiest way to get it off is to get a dental pick and use the side of the point to scrape it away. This prevents the actual tip of the pick from digging into the bone and leaving scratch marks while still removing the algae. 

[pachy-pleuro-whatnot-odon]

18 hours ago, Harry Pristis said:

What is it you are trying to say in concluding the bone is NOT mineralized?  Vascularization is not obliterated or filled-in by permineralization.  Even bones entirely replaced by exogenous minerals may preserve nerve and blood vessel foramina.  Replacement is not the common condition of Pleistocene bones in Texas or in Florida.  Even my few French vertebrate fossils from the Eocene are thoroughly mineralized (?replaced), yet show their foramina normally.

 

I guess I probably didn't express myself too clearly either, as, technically speaking, bone is, of course, even in its living condition, a mineralised tissue. What I rather meant was that without mineral infill of the vascular canals you'd get deep penetration of the vinegar into the bone, which I think would be hard to clean out entirely. However, any acid that remains would then be able to slowly break down the integrity of the specimen over time, which is, of course, an undesired consequence. That having been said, though, I've never treated bone with acid - at least, not by full inundation, so this is just how I'd feel about the matter. If this is a method you're used to applying to your bone finds from Florida then you'd definitely have the greater experience and will take this moment to learn from it

 

18 hours ago, fossilus said:

I've had decent luck removing this stuff if I catch it when it's still wet with bleach water and a toothbrush. Once it dries it's almost impossible to remove. 

I think it's from algae as it's worst when found on a fossil in a few inches of water or less. (photic zone)

 

That's why I initially suggested using mechanical tools using tools that are more likely to give way than the material you're applying them to - in this case your bone specimen. As to the external application of the vinegar I suggested, this method is rather similar as @fossilus describes for the bleach water.

[Brandy Cole]

@Harry Pristis

The light coloration did turn out to be some stubborn limestone, and a vinegar solution removed it very well.  Thank you.

 

Here are some additional pictures post clean-up.

[Harry Pristis]

Good job!

[ClearLake]

That is a very nice piece and the extra cleaning made it even better looking.  I agree that it is a cubonavicular and looks similar to the Bison that Harry posted.  Just wanted to give you some shots of a cow one so that you can compare and easily see it is not the same as yours.

 

 

 

[Harry Pristis]

Here's a line drawing for future reference:

 

[Brandy Cole]

@ClearLake @Harry Pristis Thanks for the helpful information!