More Crappy Questions - Crab, Bivalve Or Coprolite?

[GeschWhat]

Hi all,

A while back, I acquired about 160+ coprolites from the Bull Canyon Formation in Quay Co., NM. As some of you may know, I have been doing a little experimenting by dissolving them in vinegar in order to study the inclusions. Prior to dissolving them I always scan candidates with the microscope. While scanning, I came across this interesting specimen. It reminded me of the segmented worm coprolites that I found crab exoskeleton that you all helped me identify (LINK) a while back.

This specimen is quite a bit different in that it has the general shape of a crab exoskeleton, but none of the features you would expect to find on the underside of a crab nor an opening for a head. The people that collected this said that they have never found crabs in the area, but have come across bivalves. However, this doesn't really look like a bivalve to my untrained eye. What I believe to be tiny coprolites on (and possibly contained within) the specimen are the pellet shaped items on the microscopic image.

I would like to get the opinion of all you experts on crabs, bivalves, and coprolites out there. What do you think the host fossil is?

[GeschWhat]

More photos...

[GeschWhat]

...and a few more angles...

[GeschWhat]

A couple more angles

[Carl]

I agree that the micro bits look a lot like coprolites but I can't really say anything about the whole mass.

[GeschWhat]

I agree that the micro bits look a lot like coprolites but I can't really say anything about the whole mass.

Carl, I was counting on you!!! Since I initially posted I sent these photos to the couple that collected it, and they said it looks nothing like the bivalves found in the area, so I think I can cross that one off the list. A lot of the more verifiable coprolites specimens from the area do have what appears to be the same mineral composition. Because this one is on the unique side, I don't want to destroy it to see a section. I have a lot more to go through. Maybe if I find another, I'll cut one. Thanks for looking!

[Carl]

A coprolite filled with coprolites would make my heart sing! I may have seen one or two potential ones before but none yet confirmed.

[Auspex]

A coprolite filled with coprolites would make my heart sing! I may have seen one or two potential ones before but none yet confirmed.

Coprophagy is bound to be hard to prove by the fossil record, due to "alteration" of the original material.

[garyc]

Coprophagy is bound to be hard to prove by the fossil record, due to "alteration" of the original material.

It's easy to prove in modern times. I used to have a dog that would dine at the cat box.......

[Auspex]

Contemporary observation is best evidence, but forensically hard to prove after the fact...

[garyc]

Does cat litter digest completely?

[GeschWhat]

I think I found another one...will try to post photos tomorrow!

[Carl]

I'd even accept a coprolite with coprolite-filled burrows in it! Not necessarily coprophagy but a better mechanism to get copros in copros!

[GeschWhat]

Here are a couple photos of another one I found in the same batch with the microcoprolites. This one had a little bit of bone showing so I did some microexcavation with my Xacto blade this morning, but I just did enough to verify that it is bone. I don't have time to mess around downloading the micro photos right now.

Tell you what, Carl, when I go to rehome these, I'll save you one!

[Carl]

Woohoo! Thanks!