Lyme Regis Coprolite Fish Inclusion Curiosity - Otolith?

[GeschWhat]

Scanning a small coprolite from Lyme Regis, UK, I noticed this little button-shaped inclusion. I was just wondering if anyone recognized what this might be. My only guess would be an otolith. Any ideas? I'm tempted to try to remove it to get a good look at the other side. Thanks for looking!

 

[Fossildude19]

Could be a crushing tooth.  

[Harry Pristis]

Could be an otolith.  Here is one from the phosphates of Morocco.

 

[Rockwood]

Extract 

[Al Dente]

6 hours ago, Harry Pristis said:

Could be an otolith.  Here is one from the phosphates of Morocco.

 

 

Harry's object is definitely not an otolith. We went around on this one before with several experienced forum members explaining why this is not an otolith.

Here's the link-http://www.thefossilforum.com/index.php?/topic/48346-is-this-a-fish-otolith/#comment-520625

[Taogan]

Looks more like a tooth to me

[Harry Pristis]

4 hours ago, Al Dente said:

 

Harry's object is definitely not an otolith. We went around on this one before with several experienced forum members explaining why this is not an otolith.

Here's the link-http://www.thefossilforum.com/index.php?/topic/48346-is-this-a-fish-otolith/#comment-520625

 

Al Dente overstates the case . . . he doesn't believe this is an otolith, but the thread trying to identify it as something else was inconclusive (to say the least).  It is an interesting read, though . . . read it and draw your own conclusions.

[Al Dente]

Harry

I believe your object might be a plastic bead, possibly PVA that someone was using for consolidating a fossil. Have you tried soaking it in acetone?

[Al Dente]

Here are some fossil otoliths that I have found. These are Pliocene.

[GeschWhat]

I decided to try to extract it, but it was too thin. I chipped the edge a little so I quit. Here are some pictures from the side. It appears that it is no thicker than the scales that are also present. I also tried to uncover what I thought was a tooth (the pointy kind) from another part of the coprolite. That ended up to be what I think is a skull part.

 

Few questions:

• Can crushing teeth be this thin? If so, do you think it might be attached to the bone it abuts?
• Would an otolith be roughly the same size as a scale? I can't seem to find photos of any fish otoliths from the Blue/Lower Lias. Granted, I realize there can be more than one prey item in a poop. 
• Do any of you think it could just be a weird scale or some sort of ornamentation? Or maybe just rounded by digestion?

 

@Al Dente Quite the collection! I couldn't tell from the photo; do any of the small round ones look anything like this?

[Al Dente]

Lori

I don't think you have an otolith. Otoliths are made of aragonite which is fairly unstable. Early Jurassic would be very old for an otolith unless it has been replaced with some type of mineral.

[GeschWhat]

40 minutes ago, Al Dente said:

Lori

I don't think you have an otolith. Otoliths are made of aragonite which is fairly unstable. Early Jurassic would be very old for an otolith unless it has been replaced with some type of mineral.

That would explain why I couldn't find any online! 

[Harry Pristis]

4 hours ago, Al Dente said:

Harry

I believe your object might be a plastic bead, possibly PVA that someone was using for consolidating a fossil. Have you tried soaking it in acetone?

 

You have some strong opinions, Al . . . I wish your arguments were equally convincing. 

I think it's worthwhile to post these comments again:

July 28, 2014

Here is some interesting background info. Unhappily, none of the otoliths in this report resembles my object.

FISH OTOLITHS FROM THE COFEE SAND (CAMPANIAN) OF NORTHEASTERN MISSISSIPPI,
Dirk Nolf and David T. Dockery III
in Mississippi Geology, Volume 10, Number 3, March 1990.

Otolith records from Cretaceous strata are very scarce. This strongly contrasts with the many
otolith-based reconstructions of fish faunas from various Tertiary deposits. Nolf (1985) records
less than 20 valid species for the whole Cretaceous, while this number is on the order of 1,000
for the Tertiary. [This disparity] is essentially due to preservation conditions and collecting techniques.

 

A primary condition for otolith collecting is an unconsolidated sediment that can be sieved (sand,
silt, clay, or marl). ... [Otoliths] consist of aragonite, a metastable polymorph of calcium carbonate.
Decalcification often affects sediments to the extent that aragonite is dissolved, while the stable
polymorph calcite remains (e.g. oysters, pectinids, brachiopods, and echinoderms are preserved).
This is the case in the majority of the Cretaceous deposits in Europe, the continent where fossil otoliths
have been studied most intensively. Recrystallization of otoliths into calcite is rare, which explains their
absence in the fossil record of this period. [rare, but not absent, obviously]

 

[westcoast]

6 hours ago, Al Dente said:

Harry

I believe your object might be a plastic bead, possibly PVA that someone was using for consolidating a fossil. Have you tried soaking it in acetone?

While I don't know what the object is and am open to all ideas and learning...surely plastic bead is highly unlikely?

[Al Dente]

2 hours ago, Harry Pristis said:

 

You have some strong opinions, Al . . . I wish your arguments were equally convincing. 

 

 

 

Harry

I wish you would reread the original thread. Several people took the time to explain to you why this is not an otolith. I will summarize a few reasons.

 

1. Your object is a sphere- Otoliths are not spherical.

2. Your object is clear - Fossil otoliths are made of aragonite and are not clear.

3. The phosphate mines in Morocco do not preserve aragonite, therefore no fossil otoliths.

 

So far your best argument for this being an otolith is "it is the right size".  

[abyssunder]

I'm wondering if could't be something similar to a fish vertebra, but it's just a guess.

 

excerpt from here