Seeking advice on newly purchased Keichousaurus

[jasonwongzero]

Hi!  I recently purchased the following Keichousaurus Hui.  Although I have a modest fossil collection primarily consisting of Trilobites, this is my first Keichousaurus fossil.  I had a chance to inspect the fossil first hand in the store before purchasing and while it looks quite nice to me, I would appreciate feedback from this group.

 

IMHO, the piece is very attractive and presentable as a display piece (and it carried a correspondingly 'display piece' price!).  I don't have any major concerns other than maybe the piece is too nice as it is nearly symmetrical, the detail is very fine, etc.  Here is what I have observed:

 

1) The fossil is extremely 3D with well defined relief.  Bones are thick, heavy, dark and well articulated.  The fingers and toes in particular are very well defined.

2) The neck loop is very unique and the 'physical loop looks right' in that the bones go under and around each other in a believable way.

3) I did a very light acetone test on most bones, including the fingers and there was a bit of soil that came up.  I did not see evidence of ink, nor did any of the bone detail wipe off.

4) The head is very detailed with needle like bones that might be teeth?

5) The matrix is soft and from the side is clearly layered.  The back side of the matrix is flaking off and has a section that appears a little glossy...  perhaps epoxy of some kind was used to shore up a weak back side?

6) There are thin cracks/striations that cross the specimen.  These line up with the natural lines of the animal, so it does not appear that it is a composite.

7) There are no bubbles that I can see.

8) There appear to be a jumbled lump of bones in the gut...  maybe the little guy's last meal?

 

I have a ten day purchase guarantee from the seller and would love to keep this piece for display.  Would appreciate the experts in this forum to help give me some confidence as to the quality of this piece, thank you!

 

Jason

 

 

[FranzBernhard]

Thanks for sharing this with us! The pics are very good and detailed and you made a number of very detailed and educated observations.

And welcome to TFF!

 

Just my opinion, from what I have learned about this fascinating species here on TFF:

- It looks real and the neck loop is indeed very unique and very special.

- A lot of effort was put into its preparation. It was mostly mechanically preped, with maybe some acid prep somewhere in between?

- Bones look good, but I don´t know, how much bone substance was removed during preping.

- Bones are probably colorated or at least impregnated / thinly coated with something, to make them darker and more shiny. But this work was done highly professionally (in my opinion).

1 hour ago, jasonwongzero said:

The back side of the matrix is flaking off and has a section that appears a little glossy...

- It seems, that the backside would need a little bit more stabilization, maybe something to be glued on the backside. But you will get some expert advice here!

 

This is such an amazing specimen - Do you have some background info (when found, where preped, former owner etc.)?

 

And now I am waiting for all the profs here "killing" me... .

 

Franz Bernhard

[jasonwongzero]

Thank you Franz! Super helpful and I really appreciate you taking the time to reply to me. The seller has been very nice and helpful.  He seems to be a passionate fossil enthusiast first (and retailer second) and has said that he is prepping some of the paperwork that should hopefully illuminate my questions to him like location found, provenance, etc. He did mention that he has owned several keich in the past, but this was a special piece for him.  He did in fact have other beautiful keiches in the store that day but this was head and shoulders nicer than the others due to both display and detail. 

 

Looking forward to others' opinions!

 

Jason

[JohnJ]

@jasonwongzero 

Please remember to keep this discussion focused on the fossil, not the seller.  Other members are very familiar with these type fossils and should be along shortly to offer their input.  Thanks for your help.

[steelhead9]

As good as they get in all ways! A real keeper.

[Bobby Rico]

I think it is fantastic something to wright home about. 

[RJB]

I can see both scribe marks and air abrasion burn and a nice prep job for sure.  Im not very knowledgable about these and am only guessing, is the body showing the ventral side and the head the dorsal side?  Just wondering.  Nice specimen though.

 

RB

[snolly50]

1 hour ago, RJB said:

the body showing the ventral side and the head the dorsal side?  Just wondering.  Nice specimen though.

Yes, precisely the observation I was about to post. The specimen displays some interesting contortion. I can't tell from the photo; do the neck verts reflect the suggested "twist?" To my eye from the photos. it is very nice and much more carefully prepared than the typically available offerings.

 

9 hours ago, jasonwongzero said:

The head is very detailed with needle like bones that might be teeth

Yes, teeth.

 

From what I can see, I like it and would be pleased to display such a piece. 

[JarrodB]

One of the nicer ones I've seen. 

[Fossildude19]

Awesome.  

Thanks for posting it for us. 

[jhw]

Agree with the others. That's a dandy. Congrats!

[Mark Kmiecik]

The best advice I can give you is to send it to me. Thanks in advance.

[Crazyhen]

This is a nicely prepped specimen of Keichousaurus.  It seems to be mechanically prepped with both air abrasion and acid.  The bones look fine to me, many nicely prepped specimens show dark and shiny bones and very fine details.  I especially like the teeth that remain after prepping. You may compare to the one below for what it looks like for the unprepped natural form with fine details.

[aplomado]

That is a lovely specimen!

Lucky for you!!!

[Pemphix]

Very nice piece with a good preparation....

Maybe last part of the tail has been added from another species (?), imo at least glued.

Definitely glued/added foreign matrix (without fossil) on both sides of the slab (Head and tail).

 

[jasonwongzero]

5 hours ago, Pemphix said:

Definitely glued/added foreign matrix (without fossil) on both sides of the slab (Head and tail).

Ah, yes, I see now since the matrix patterns don't line up.  I'm ok with the matrix glue, but I appreciate you pointing this out!

[Roses]

@jasonwongzero In case you ever pop back in to the forum, your Keich looks eerily similar to one I recently purchased which turned out to have a fake skull. The prep job on the body and the appearance of the skull both match almost exactly to my specimen. I’m also skeptical of yours for two reasons: the body is ventral while the skull is dorsal (like mine), and the loop is very convenient given where the matrix is broken - if the neck weren’t looped, it would have been broken off and the head would not be present. 

See the discussion about my specimen here:

https://www.thefossilforum.com/topic/137605-composite-keichousaurus/

 

You may be able to test it by getting the matrix wet (to see if there is differential absorption around the head, where a polymer may have been used), or viewing it under a jeweler’s loupe at 30-60x magnification.

Edited December 2, 2023 by Roses
Typo

[jpc]

I disagree on the dorsal/ventral.  The body and head are both shown dorsally.  In ventral view, you would not see those verts dominating the body.  The dorsal verts seem to have been damaged in prep as they are just cylinders.   

[Roses]

39 minutes ago, jpc said:

I disagree on the dorsal/ventral.  The body and head are both shown dorsally.  In ventral view, you would not see those verts dominating the body.  The dorsal verts seem to have been damaged in prep as they are just cylinders.   

The coracoid, pubis and ischium are all clearly visible as in ventral presentation (first image). In dorsal presentation you do not see these bones (second image).

 

The morphology of the vertebrae is normal for ventral positioning and they are well-preserved.

 

Edited December 2, 2023 by Roses

[Roses]

@jasonwongzero Looking more closely at the neck, I don’t see anything suspicious about the bend until the bit where it crosses over. If you follow the natural bend in the neck, it looks like the (probably ventral) head may be buried under the rest of the body, which would explain why the first few cervical vertebrae are elevated. I’m wondering if it may be a “complete” skeleton but with an extra, fake head added for aesthetic reasons, since it wasn’t possible to prep out the real head. After the point where the neck crosses, those last cervical vertebrae look suspiciously similar to the fake ones on my specimen, and so does the skull.

 

We could also try counting the cervical vertebrae.

[Roses]

@jasonwongzero

Keichousaurus has 25 cervical vertebrae (source). I count 27-28 visible vertebrae on your specimen, and if authentic, there should be ~3 hidden where the neck crosses, bringing the total up to ~30. There are 22-23 visible vertebrae before the neck crosses over, which does suggest to me that the head is likely buried under that crossover point.

 

With the correct number of vertebrae, this would be the approximate position of the head:

Edited December 2, 2023 by Roses

[FranzBernhard]

5 hours ago, Roses said:

With the correct number of vertebrae, this would be the approximate position of the head:

Fossil detective in action again!

 

What do you think about the detailed head with all its teeth? Including a vein running through it and the matrix.

 

Franz Bernhard

[jpc]

I hate being wrong but I will eat my hat.  You are right, Roses.  I was looking at the gastralia which seem to go under the ribs therefore implying that we are looking at a dorsal view.  But looking a bit closer, I think many of the gastralia have ben prepped off to reveal the ribs.  They don't go under the ribs, they just end at the ribs.

[Roses]

8 hours ago, FranzBernhard said:

Fossil detective in action again!

 

What do you think about the detailed head with all its teeth? Including a vein running through it and the matrix.

 

Franz Bernhard

The anatomy of the head looks off to me. It’s very detailed as you say, but the teeth are too uniform and evenly distributed as with my specimen, and the proportion of the skull which is made up by the nostrils (nasals? nose holes?) and premaxilla is too large. 
 

The first three images are from Chinese Paleontological papers, the last is OP’s specimen. The nostril/premaxilla portion is marked in red.

 

[FranzBernhard]

1 hour ago, Roses said:

The anatomy of the head looks off to me.

Indeed, looks somewhat different.

What about interspecies variation / potential subspecies? Or ontogenetic variation? Female/male differences?

Concerning the teeth, the ones in the second pic are also quite regular, at least compared with the teeth of the specimen in question (last pic).

Ok, now I am noticing the difference of the regularity of the teeth in the most frontal part.

Franz Bernhard