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Hello!

 

I asked this question in the Facebook group so I apologize if any of you are seeing it for a second time, but it was buried in a comment chain so I’m hoping to get a few more expert eyes on it.

 

I received this beautifully prepared Keichousaurus today and it’s truly awesome to see it in person, but now that I’m able to inspect it more closely I’m thinking it may be a composite. There are a few things making me lean that direction:

 

1) There is an obvious mismatch in the patterns on the matrix, both front and back, when comparing the chunk that the body is on to the chunk that the skull is on. For example, the partial fish fossil on the righthand side just abruptly stops at the seam (last photo, blue arrow) … but it’s maybe possible that this is due to variable flaking/weathering and reattachment

2) The head is dorsal while the body is ventral … but I know it’s possible for this to happen naturally if the neck is twisted

3) The white “veins” that appear to run across both plates (skull and body) are, I think, true calcite veins in one plate and scratches intentionally placed to match on the other. For example, the red arrow in the last photo points to a junction where a true calcite vein from the body plate should cross the skull, but no vein is visible in the skull. A “vein” reappears above the skull but I believe this is just a surface scratch.

 

On the other hand, the skull is perfectly sized and aligned to the “horns” (retroarticular processes) present on the body plate. This seems incredibly difficult to achieve in a fossil of this size.


This specimen was prepared in the US and I have no reason to believe the skull is fake, but the uniform spacing and shape of the teeth also looks off to me. That may just be due to incomplete preparation of the area, I can’t tell even under 10x magnification.

 

In any case it’s beautiful to look at, I was just a little disappointed to see that it may be a composite. What are your thoughts?

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23 minutes ago, Roses said:

2) The head is dorsal while the body is ventral … but I know it’s possible for this to happen naturally if the neck is twisted

Can you see a twist in the neck?

 

Would you like to provide a side view of the top part?

 

Franz Bernhard

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12 minutes ago, FranzBernhard said:

Can you see a twist in the neck?

 

Would you like to provide a side view of the top part?

 

Franz Bernhard

Hello Franz!

 

It’s so lovely that you’ve responded, thank you for engaging me on this as well as the curious white crystallized Keichousaur earlier this year.

 

I can’t see an obvious twist in the neck, but it’s very hard to tell. The ~four uppermost vertebrae are not as well preserved/prepared as the others, and could be in alignment or turned any which way. I’ll try to get a side view photo in the morning.

Edited by Roses
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Looks pretty good to me. It may be a composite, but if it is, it is a high quality one.

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    Tim    VETERAN SHALE SPLITTER

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Not super well versed on keich material but this doesn’t look composite to me. Everything seems to line up right for the most part. 

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Nice one! Though the neck looks a bit strange:headscratch:

Edited by trilobites_are_awesome
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Cheers!

James

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I’m actually not seeing a difference in the slabs….I think there was a small sliver missing where it broke. Maybe a mm or so plus or minus. Wich is causing the slight mismatch of the matrix pattern and skull at the joint where it was reattached . Wether it was removed to make the joint fit together better or wether it was missing before I couldn’t say. 

Edited by Randyw
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9 hours ago, FranzBernhard said:

Can you see a twist in the neck?

 

Would you like to provide a side view of the top part?

 

Franz Bernhard

 

Here are some more images. The first is the joint near the fish fossil. The second is the joint near the Keichousarus head.

 

It's heartening that this doesn't look composited to some of you all, I'm just having a hard time reconciling the differences in the matrix.

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Thanks for the additional pics!

Some of the veins seem to run through both parts, but you have noticed otherwise (vein in one part, scratch in the other part). Would you like to check that again?

 

27 minutes ago, Roses said:

I'm just having a hard time reconciling the differences in the matrix.

Maybe the two parts have been acid-prepped separately and glued back together afterwards?

 

1 hour ago, Randyw said:

I think there was a small sliver missing where it broke. Maybe a mm or so plus or minus. Wich is causing the slight mismatch of the matrix pattern and skull at the joint where it was reattached .

Yeah, and this was possibly already recovered in two pieces.

 

I am in the non-composite camp at the moment (just reattachment of two no longer 100% perfectly fitting parts), but waiting for detailed analysis of the vein pattern.

 

Franz Bernhard

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1 hour ago, FranzBernhard said:

Some of the veins seem to run through both parts, but you have noticed otherwise (vein in one part, scratch in the other part). Would you like to check that again?

 

Hopefully it will be possible to follow this. The red arrow indicates a true calcite vein on the body plate. The blue arrow indicates a true calcite vein on the skull plate.

If you follow the red vein from the body plate to the skull plate, it doesn't continue through the skull. If you follow the blue vein from the skull to the body, it doesn't cut through the scapula or the rest of the body.

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Another angle, the red vein doesn't look to me like it cuts all the way through the skull plate, but it's hard to tell because there is another vein next to it that does.

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Here is the back of the plate. Red vein doesn't continue on the skull plate, blue vein doesn't continue on the body plate.

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This third, green vein cuts all the way through the body plate, but then seems to just disappear into a scratched/polished area on the skull plate.

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I can't find any veins that convincingly cut through both plates.

If the veins matched up or were clearly offset by a mm or so, I would be convinced that the skull plate was just reattached a bit higher or lower than it originally sat, causing a different limestone layer to be exposed during acid prep/polishing. That would explain the mismatched patterns. But I can't figure a way to move the skull plate so that the calcite veins match up.

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Here’s a blowup with parts I marked consistent on both plates within just a millimeter or so…

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Edited by Randyw
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And a little more blown up. And the heads with where I think the neck twist is… dotted red line is top vertabrae I think.. see how they twist to the right?

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Edited by Randyw
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I realize I don’t have it in hand but from the pictures I’d be fairly confident if it was in my collection….

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7 hours ago, Randyw said:

Here’s a blowup with parts I marked consistent on both plates within just a millimeter or so…

 

 

The black lines you've marked appear to match up, but what I was trying to show with my most recent set of photos is that I don't think they are actually continuous calcite veins. Both plates (skull and body) have real calcite veins, but I think someone has intentionally scratched the front of the matrix to create the appearance that the calcite continues from one plate to the other. The possibly-faked "veins" on the front don't show on the back side. But it's not a perfect science, and I'd love to be wrong.

 

I do think it's possible the neck is twisted, but those top vertebrae are a bit beaten up so it's hard to be sure, even under magnification. I can follow the alignment of the vertebrae until the top 4 or 5, then I couldn't say with any confidence where the processes are.

 

I'm hoping the seller still has some photos of this specimen from before preparation, they would be interesting to check out. I might also call the local vet tomorrow and see if I can get it X-rayed, for fun more than anything else 🙂

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2 hours ago, Roses said:

but I think someone has intentionally scratched the front of the matrix to create the appearance that the calcite continues from one plate to the other.

I can not see a difference, based on the pics. I think, at least one vein continues from the body to the skull plate (red arrow). I don´t know, why it doesn´t appear in the skull itself? Possibly some sculpting done on the skull?

With the specimen in hand and with a hand lens, it could be possible to decide, what is a vein and what is a scratch.

Franz Bernhard

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I don't think it's a composite, it looks just fine in my eyes.  The plate might have been broken into two pieces (along the calcite vein) and glued back together.  I am impressed by your detailed examination of the plate.

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Thanks all very much for your thoughts! It's comforting that I seem to be the only skeptic 🙂 

If I can convince one of the local vets to X-ray it I will report back in case anyone is interested in seeing the result. Else it will just be proudly displayed in my living room!

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@FranzBernhard @Randyw @Crazyhen

 

Just thought you all might be interested in the resolution - it’s neither an authentic complete skeleton nor a composite, it’s a restoration 😂


The seller reached out to the preparator who was listed in their records, and that individual said they hadn’t prepared it after all, and that it did appear to be a composite.

 

The anatomy of the nostrils and teeth was bothering me so I kept trying things to suss out whether it might be a fake, and finally found something that seems diagnostic.

 

When wet, you can see the porous matrix is darkened except around the skull where some film (wax or a polymer of some sort) is making it less permeable. The water also lifted some pigment on the skull which I assume was acrylic paint or something else water soluble, and white (resin or similar) is visible underneath.
 

The origins of the fossil are unknown since the seller’s records were not correct (I think the records were inherited from a prior owner or colleague). It’s completely bizarre to me that someone would go to the trouble of meticulously preparing an incomplete skeleton and casting or sculpting a skull for it, when complete skeletons are relatively cheap. But I suppose it happens all the time with trilobites and similar. The professionalism of the prep and resto makes me wonder if it was a museum piece at some point.

 

Photos below. I’ve also included one under 395nm UVA, which (unhelpfully) showed no fluorescence. I haven’t tried short wave UV. Lastly is a photo of an authentic skull, showing teeth more asymmetrically clustered towards the front of the mouth than on this replica. 
 

 

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Great detective work! Thanks for keeping us up to date!

 

So, everything within the red line is a cast or sculpted. That finally explains the missing veins through the scull and the different orientation of body and skull, without an obvious twist in the neck.

 

Furthermore, this was originally a decapitated Keicho? Does this occur often with them, preservation without head?

 

Again, you are a superb scientist and detective @Roses! Thanks again!

 

Franz Bernhard

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Just now, FranzBernhard said:

So, everything within the red line is a cast or sculpted. That finally explains the missing veins through the scull and the different orientation of body and skull, without an obvious twist in the neck.

Yes, I think so! Leagues above any other Keich fake I’ve seen. And impressive detail work by the restorer scratching those fake veins into the matrix.
 

2 minutes ago, FranzBernhard said:

Furthermore, this was originally a decapitated Keicho? Does this occur often with them, preservation without head?

My guess is that the skull was most likely attached, but was on the other side of a vein and was irreparably damaged when the plate was split from the bed. I’ve never seen an intact plate with a missing head, but I’ve seen many plates broken somewhere through the cervical vertebrae. But who knows, it’s also possible it was decapitated at some point in the Triassic. 

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