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FF7_Yuffie

Hi,

 

I am interested in this. Sold here, seller says its ok to have a second pair of eyes look it over.

 

From Holzmaden. Slab is 50cm. Jaw is 14cm. Seller thinks jaw has been added. My main concern is have the vertebra been added too?

 

Thanks

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47AB770C-C1CA-44C0-973D-B6817E9E6EAD.jpeg.fd7170f747d9b53dc3f9c64c0ae35a68.jpeg

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Ludwigia

I must say, it does look a little strange and untypical for a piece from this site, so your suspicion is well-founded, but it's difficult to determine from the photo. It may be that the large vertebrae were added, but I'm not sure about the smaller ones.

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Paleoworld-101

I also thought the rostrum section with teeth was added on. And if that was added, then some of the vertebrae are likely to have been added too. Whether you proceed depends if you're comfortable with a composite piece or not. 

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FF7_Yuffie
35 minutes ago, Paleoworld-101 said:

I also thought the rostrum section with teeth was added on. And if that was added, then some of the vertebrae are likely to have been added too. Whether you proceed depends if you're comfortable with a composite piece or not. 

 

 

A little bit, like just the jaw, im ok with, but seems like this is too composited for me. 

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pachy-pleuro-whatnot-odon

I also saw this piece yesterday, but something didn't feel quite right about it - and that's not even considering the over-use of consolidant (sure, such a consolidant is often applied to pieces from Holzmaden to preserve the Dactyloceras-ammonites contained in the shale, I just don't find it very attractive or necessary for most vertebra material from this locality). One of the things that set me off is that I haven't ever seen a slab full of pyritized ammonites from this location contain any bone. That is, as far as I'm aware, bone and ammonite death beds come from entirely different stratigraphical layers. It also seems highly unlikely to me that you'd find ichthyosaur vertebrae laid out like that. You may find a string of vertebra, sure. May be there's a rupture in the string, offsetting one part of it. Fine, I'll also swallow that. But for such a perfect line of tail vertebrae to have another almost perfect line lying next to it seems highly unlikely. That's because the taphonomic processes that lead to the one condition necessarily exclude the other - i.e., in order to preserve a perfect line of vertebrae, you need quite calm depositional conditions, probably combined with rapid sedimental covering so as to prevent predation. Sure, some vertebrae may displace due to underwater currents, but not a whole string. That is, unless some other organism interacted with the carcass. But then you'd be contradicting the calm depositional environment, wouldn't you?

Same goes for the big vertebrae. Sure, these may have become displaced under the influence of currents and predation, but the tail section next to it contradicts this type of taphonomy. Besides, these vertebrae would need to come from a part much anterior on the body, which makes it odd that only those vertebra would've been displaced. As with the jaw - which is the most blatant and obvious addition to the composition for the fact that it's so cleanly cut off on both sides, without any bone or tooth debris around it - I therefore believe the whole slab to be a composite aimed at a target group that likes both the pyritized ammonites as well as ichthyosaur fossils. Although in my mind unfortunate - as I prefer my fossils in a more natural state - this is, alas, not an uncommon practice with pieces coming from Holzmaden. A lot of them have been slightly altered to improve their aesthetics - and in doing so, have lost much of their scientific value.

 

Still, if you look at the asking price, the piece is not that badly priced. Forum rules don't allow me to go in to details here, but if you consider the components separately, this definitely would be a worthwhile purchase. Just know that it's a composition, or plan on dismantling it for its parts...

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pachy-pleuro-whatnot-odon

(I'm just a collector too, though. And even though I've collected from Ohmden myself, I've never been lucky enough to find any vertebrate material there. So if you want some real expert opinions, I'd like to refer you to either @belemniten or @Trahho, who I know have build excellent collections from the area.)

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FF7_Yuffie
43 minutes ago, pachy-pleuro-whatnot-odon said:

I also saw this piece yesterday, but something didn't feel quite right about it - and that's not even considering the over-use of consolidant (sure, such a consolidant is often applied to pieces from Holzmaden to preserve the Dactyloceras-ammonites contained in the shale, I just don't find it very attractive or necessary for most vertebra material from this locality). One of the things that set me off is that I haven't ever seen a slab full of pyritized ammonites from this location contain any bone. That is, as far as I'm aware, bone and ammonite death beds come from entirely different stratigraphical layers. It also seems highly unlikely to me that you'd find ichthyosaur vertebrae laid out like that. You may find a string of vertebra, sure. May be there's a rupture in the string, offsetting one part of it. Fine, I'll also swallow that. But for such a perfect line of tail vertebrae to have another almost perfect line lying next to it seems highly unlikely. That's because the taphonomic processes that lead to the one condition necessarily exclude the other - i.e., in order to preserve a perfect line of vertebrae, you need quite calm depositional conditions, probably combined with rapid sedimental covering so as to prevent predation. Sure, some vertebrae may displace due to underwater currents, but not a whole string. That is, unless some other organism interacted with the carcass. But then you'd be contradicting the calm depositional environment, wouldn't you?

Same goes for the big vertebrae. Sure, these may have become displaced under the influence of currents and predation, but the tail section next to it contradicts this type of taphonomy. Besides, these vertebrae would need to come from a part much anterior on the body, which makes it odd that only those vertebra would've been displaced. As with the jaw - which is the most blatant and obvious addition to the composition for the fact that it's so cleanly cut off on both sides, without any bone or tooth debris around it - I therefore believe the whole slab to be a composite aimed at a target group that likes both the pyritized ammonites as well as ichthyosaur fossils. Although in my mind unfortunate - as I prefer my fossils in a more natural state - this is, alas, not an uncommon practice with pieces coming from Holzmaden. A lot of them have been slightly altered to improve their aesthetics - and in doing so, have lost much of their scientific value.

 

Still, if you look at the asking price, the piece is not that badly priced. Forum rules don't allow me to go in to details here, but if you consider the components separately, this definitely would be a worthwhile purchase. Just know that it's a composition, or plan on dismantling it for its parts...

 

Cheers.

 

Yeah, I saw other, much smaller vert columns or jaw pieces usually for sale for much more. But fact it's more than likely a composite puts me off--I'm just not a fan of them, even though some, like this one, can look very nice I much prefer natural assemblages. Plus, I have zero prep experience to remove the bits and display seperate

 

Thanks for taking a look at it.

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DatFossilBoy

@pachy-pleuro-whatnot-odon thank you for the information and detail. I wasn’t aware of this.

I see what you mean now, as in the ray of verts running parallel have been added on as well as the bigger verts and jaw.

I just need to find now a buyer willing to ignore that the composition isn’t original but is just interested in the bones...

One last thing, although it’s uncommon to see ammonites and bones on the same slate, it does occur, like in this fossil I found online.

Thanks again and regards.

1D2E5418-4695-432D-B7A7-B2B2FF11D10D.jpeg

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Didn't we see this slab on the forum recently?  I seem to remember it and thinking... is that snout piece just sitting on top of the slab? Snout pieces that are so perfectly broken suggest to me that the snout was prepped out of a different piece of rock that was itself broken where the snout is broken.  Does that make sense?

 

 

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pachy-pleuro-whatnot-odon
6 minutes ago, jpc said:

Didn't we see this slab on the forum recently?

Yes, you may have seen it on the sales board :)

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belemniten

Thanks for the flowers @pachy-pleuro-whatnot-odon. I mostly agree with you. Besides that its a composition it was also very badly prepared. Especially the verts.               But bones and ammonites actually occur quite often in the same layers. I have also some examples. The usual preparation method to prep bones from there is sandblasting, which destroy the ammonites if you arent extremely careful. 

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pachy-pleuro-whatnot-odon
4 minutes ago, DatFossilBoy said:

@pachy-pleuro-whatnot-odon thank you for the information and detail. I wasn’t aware of this.

I see what you mean now, as in the ray of verts running parallel have been added on as well as the bigger verts and jaw.

I just need to find now a buyer willing to ignore that the composition isn’t original but is just interested in the bones...

One last thing, although it’s uncommon to see ammonites and bones on the same slate, it does occur, like in this fossil I found online.

Thanks again and regards.

1D2E5418-4695-432D-B7A7-B2B2FF11D10D.jpeg

Thanks for taking it so sportingly, as I can imagine it not being what you had hoped to hear about your fossil - which you have undoubtedly cherished and invested in, even if right now you'd like to pass it on. We all get duped sometimes, and your positive reaction only goes to show for your honest intentions of finding a good new place for it.


I do feel, however, that I should still react to the second part of your message. For, although I may indeed have seen some plates that combine ichthyosaur fossils with pyritized ammonites, these occasions are rare and, as my memory serves me, exclusive to the commercial context. Moreover, in those few examples that come to mind, the ichthyosaur is frequently positioned in a lower layer of the plate, having been freed of the overlying matrix that contains the ammonites. Having visited many of the important museums in Baden-Württemberg, close to Holzmaden, and having created quite a photographic reference collection, I find no specimens of ichthyosaur fossils that combine the two.

 

The specimen you illustrate here is interesting, in that respect, as it seems to lie in some kind of depression, slightly lower than the surrounding matrix. Although, if you look closely at the traces of the air scribe, you'll notice that it's actually the two ammonites above the ichthyosaur, as well as the area with ammonites to the left and below it, that are lying on a lower level. To me this already looks somewhat unusual, though it is possible that this is simply due to a complex layering in the shale, further proof of which can be seen in what I - with my limited field experience - have come to consider fault lines or ruptures within the Posidonia Shale, areas where one layer of shale breaks abruptly along a diagonal plane, here seen in the area of the photograph to the top left. However, if you look at the matrix around the back of the ichthyosaur, just prior to the tail flukes, the matrix is of a much lighter colour than the matrix to the top of it. The lighter coloured matrix also lacks the natural patterning observed in the darker area and seems to, instead, terminate abruptly. Of course an argument can be made that this is due to the fossil having been prepared using a sand-blaster, which undoubtedly will remove such traces. But seeing as this bit of matrix is not entirely smooth and shows traces of scraping below the tail part, my feeling is that this is artificial infill of matrix. In fact, the same can be seen more towards the front of ichthyosaur and below it (you can see it spill over onto the larger ammonite in front of the ichthyosaur's chest).

 

Then there's the clear black outline of the what's supposed to be the body shadow of the ichthyosaur, comprised of preserved skin. But, as I hope will be clear from the images below, such outlines are hardly ever perfectly preserved and as clearly outlined as is the case here. Instead, it is common practice with Holzmaden fossils to either enhance, or completely add from scratch, such outlines. What's more, I doubt such outlines would so cleanly continue atop an ammonite bed as in the case of the dorsal fin of this specimen.

 

IMG_3480.thumb.jpg.d03de1b903739dfb034c248b6cd53fc2.jpgIMG_3479.thumb.jpg.f6b7ddfeb203b6c575b7b482861ef5c9.jpgIMG_3461.thumb.jpg.063322cedcf9da3eaa0670dd80199bcb.jpg

 

Taken altogether, I therefore believe that this specimen too, has seen significant manipulation, and may even had been inserted into a plate with ammonites (although the head makes me wonder, as this part seems quite okay to me).

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pachy-pleuro-whatnot-odon
20 minutes ago, belemniten said:

But bones and ammonites actually occur quite often in the same layers. I have also some examples. The usual preparation method to prep bones from there is sandblasting, which destroy the ammonites if you arent extremely careful. 

See, that's what we needed an expert in local material on ;) I was under the impression that bones an ammonites were found in different layers, with those containing the bones and teeth rather containing more of the Posidonia muscles :)

 

And so I've learned something new today! :D

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belemniten
25 minutes ago, pachy-pleuro-whatnot-odon said:

See, that's what we needed an expert in local material on ;) I was under the impression that bones an ammonites were found in different layers, with those containing the bones and teeth rather containing more of the Posidonia muscles :)

 

And so I've learned something new today! :D

There are layers in which you can find beautiful ammonites but vertebrate fossils are very rare. And in the layers with the more common vertebrates are ammonites often not that well preserved but they still occur (sometimes quite often). So your impression is not completely wrong. 

By the way I really enjoy reading your posts! Keep up the good work! :)

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pachy-pleuro-whatnot-odon
2 hours ago, belemniten said:

There are layers in which you can find beautiful ammonites but vertebrate fossils are very rare. And in the layers with the more common vertebrates are ammonites often not that well preserved but they still occur (sometimes quite often). So your impression is not completely wrong.

At least it looks like I've been searching the right layers then, even if I haven't found anything yet...! :Confused05:

 

2 hours ago, belemniten said:

By the way I really enjoy reading your posts! Keep up the good work! :)

Thanks! It's always nice to hear that others enjoy what you're doing! :D

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