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On my last visit to the Wilson Clay Pit in central Texas I stumbled across this curious piece.  It is approximately 6 cm long and 1.5 cm wide.  The surface is irregular and rounded.  Near one end, an object about 5 millimeters in length, that looks like a brachiopod or pelecypod is attached.   The object looks partially buried in the surface of the piece.  The piece is below.  The scale is in centimeters.

 

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Below is a close-up of the attached object...

 

DSC_8613.thumb.jpg.ae86fb147d855fd044a326896c1db0ae.jpg

 

I can see three possibilities.  Its geological (matrix) with an attached bivalve (if it is a bivalve).  Its an infilled burrow of a bivalve.  Or, most enticingly, its a coprolite of a rather large aquatic animal.  The Wilson Clay Pit is a well known Paleozoic shark tooth site.  I have tried to look up shark coprolites from the Paleozoic, but they seem to have a more regular shape.  The 'bivalve' on the side is unlike any of the shells from the locality that I'm familiar with.  Could it be undigested remains of something else?

 

Any opinions would be greatly appreciated.

 

 

 

 

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DPS Ammonite

How about posting a photo of the whole shell so we can give an ID for it.

 

Here is a good guess for an ID, a brachiopod that occurs in Pennsylvanian rocks in the area: Meekella.   See: http://pennsylvanianatlas.org/genera/meekella/

 

Meekella sp. from the Keechi Creek Fm. of Palo Pinto County, Texas (KUMIP 6826).

Meekella-sp-KUMIP6826-Plate-800px.jpg

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It looks more like a coprolite than a burrow to me. It is hard to say from the photos if it is an inclusion or if the object (bivalve fragment?) just adhered to the surface as the poo settled into the sediment. Very interesting either way!

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Since a shark coprolite would have a spiral groove running the length of the specimen we can rule that out. For it to be from another marine (not just aquatic) animal you would have to consider what animals would be the right size to make a guess but even then it would only be a guess without something to confirm it. I think the usual diagnostic method is to cut a thin section to look for undigested remains in the kind of quantity normal for a coprolite, not just a single attached shell. The researchers who do this have probably seen enough suspect material to know whether it's worth a try but I don't know where you would take it in your area.

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doushantuo

some remarks:

sharko2n.jpg

shark2on.jpg

 

will look at the bibliography to see if anything  selachian coprolite-related turns up

 

 

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Thanks everyone!  I was hoping Geshwhat would respond!

 

BobWill, thanks for responding.  I agree with you that the piece is probably not shark since, as you say, they have the spiral groove running around their coprolites.  Is it possible that it is from another vertebrate?  It's from the Pennsylvanian/Permian boundary.  Could it be an early amphibian coprolite?  Has anything like that been found in the Virgilian deposits in central Texas, or from the Wilson Clay Pit specifically?

 

Thanks again everyone.  DPS Ammonite, I'll try to post a full picture of the 'brachiopod' this afternoon.

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Sorry, I'm the wrong one to ask about what it might be. I haven't heard about any local finds other than shark and the fecal-lined burrows that are found in Pennsylvanian and Cretaceous deposits here. There are plenty of more experienced Texans here who might know though.

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It is almost impossible to know what type of animal created it. As Bob Will said, it is not a spiral, so sharks, rays and the like are out. Usually, the best we can do is determine the diet of the producer. Sometimes we can make educated guesses. If a coprolite such as yours had no inclusions and there were a lot of croc teeth in the area, it would be possible that it came from a crocodilian of some sort because we know modern species have a very acidic digestive system. If we find a theropod tooth in a larger coprolite, we know that their teeth would break off and they would ingest them along with their prey. So in that instance there is a good chance that the theropod produced it. The best you can do is figure out what creatures were around at that time and rule out those that were too small to have produced it or are known to have specific morphology (as with sharks/rays/etc.). I have checked into having thin sections done and found it to be expensive. I tend to shy away from destructive testing unless I have a lot of similar specimens.

 

I don't know if you missed my first post, but I think it is a coprolite. Based on the photo of the bivalve, I can't tell if it is embedded in the coprolite or just affixed to the surface. Therefore, I can't say if it was ingested or the poop just happened to land on it. Regardless, I think you have a mighty fine piece of poop there! :D

 

@doushantuo that was a great paper. I hadn't seen it before - thanks for sharing!

 

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Thanks @Geschwhat.  I figured that we could never identify the animal perpetrator.  But since it didn't match any known sharks or rays from the locality, it immediately got my curiosity juices flowing.  I, too, had never heard of any vertebrate fossils except for the sharks, so I was wondering if anyone had found anything amphibian or reptilian.  Anyway, I think it is poop as well, and will label it as such in my collection.  Thanks again!

 

@DPS Ammonite, I took a few more pics of the inclusion, and can't make out enough detail to identify it with certainty.  However, one side does appear to be coated in the same material as is seen on the surface of the specimen (pictures 2 &3), so it looks like it may have been deposited with the specimen, not adhering to it after it landed on the sea floor.  But, that's just my theory...  The pictures are below...

 

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It looks to be a continuity in color and texture between the brachiopod/bivalve and the main mass, so I think the "object" might be an inclusion, which makes me believe that the whole ensemble could be a coprolite, but I'm wondering, who could be the holder of the "treasure" in this case. A creature eating brachiopods/bivalves, or it was picked up accidentally and dropped out as a regurgitate, or just simply pushed out as phaeces (-coprolite)? :headscratch:

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20 hours ago, abyssunder said:

It looks to be a continuity in color and texture between the brachiopod/bivalve and the main mass, so I think the "object" might be an inclusion, which makes me believe that the whole ensemble could be a coprolite, but I'm wondering, who could be the holder of the "treasure" in this case. A creature eating brachiopods/bivalves, or it was picked up accidentally and dropped out as a regurgitate, or just simply pushed out as phaeces (-coprolite)? :headscratch:

I was kind of thinking the same thing after seeing the latest photos. It almost looks like it was partially digested. Since their doesn't appear to be others, maybe incidental consumption?

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