Any Repair or restoration on these mosasaur jaws ????

[Guns]

Hi everyone ! i need a bit of help .   I recently found the mosasaur jaw that i really like and in my budget range so i just want to make sure before buying this 2 . Any repair / restoration ? or any red flag on this 2 jaw pieces ???  

Seller said to me that no Repair / restoration on this two jaw .

 

Jaw number 1 

 

Jaw number 2 

 

 

as always thank you in advance guy !

Regard

Guns

 

[ThePhysicist]

I don't see any issues at first glance, but there might be some restoration in that white space on the first jaw. They both look like Pluridens serpentis. @LordTrilobite@Praefectus@pachy-pleuro-whatnot-odon

Edited August 4, 2021 by ThePhysicist

[LordTrilobite]

Both jaws look pretty good. I don't see any red flags. I'm not seeing any clear evidence for the teeth being placed. So I'm thinking these might just be all original. With the one tooth sticking out it might have been repaired on jaw 2. Jaw 2 also looks like it might have been repaired along that break on the bone.

Both look like partial dentaries.

 

Jaw 1 looks like Prognathodon or Eremiasaurus. Dentary tip of a left jaw.

Jaw 2 looks like a halisaurine. Perhaps Pluridens serpentis as ThePhysicist suggested. Also looks like left dentary. But we're seeing the inner side of roughly the middle of the jaw.

[Troodon]

I also believe the top jaw and teeth were placed on that matrix slab as evidenced by the different colored matrix around the jaw and teeth.  Cannot tell on the second  one

[Praefectus]

There is something strange going on with the top jaw. At least two of the teeth were placed and there appears to have been some sculpting. 

 

Bottom jaw looks find. Definitely halisaurine. Either Pluridens serpentis or Halisaurus arambourgi. 

[pachy-pleuro-whatnot-odon]

I agree with most of what's been said already.

 

Jaw 1, while on its original matrix (as can be seen by how the matrix connects to the mandibular bone in the third photograph), has something going on with its teeth. While the teeth all seem to belong to the same species - as far as I can make out from them having an anterior but not a posterior carina, Eremiasaurus heterodontus - they seem to have been reattached to the jaw. To me this explains the slight discolouration around the teeth, where either A. some matrix may have been added to smooth out areas around niches carved out to fit the teeth into; or B. different amounts of glue applied may have caused a colour difference. It's hard to say whether teeth and jaw would've originally belonged together, however.

 

In addition, the lighter coloured area of the jaw may have had some restoration done to it. But seeing as there's still bone texture visible even in that area on the first photograph, I suspect that, rather, the glue was applied differently here, if at all (the glue used by Moroccan preparators has a tendency to crack and flake under certain circumstances). That is, the yellow colouring on the rest of the jaw bone is due to a dirty brush having been used in which fine particles of the matrix acted as a kind of paint. If you were to remove the thin layer of glue on top using a knife or needle, for instance, the colour of the bone itself will be white. It could therefore be that a clean brush was used for the initial bit of jaw that we consider discoloured, so that it remained white while the rest got painted over with glue.

 

The second jaw looks a lot more natural and is quite cool with its resorption pits showing (which is only visible on the inside of the mandible). No doubt about this piece being halisaurine, though better photographs of the teeth would be needed for proper identification - Pluridens serpentis namely has striations around the base of the crown, whereas Halisaurus arambourgi does not. However, based on the size of both teeth and robustness of the jaw, as well as the fact that the teeth are packed quite closely together, I'd say P. serpentis is the more likely option.

[JohnJ]

Based on these photos, I think the first jaw is an artful fabrication.  The linear grain of the bone is uniform up to the planted teeth.  The foramina appear carved. 

 

I don't see the point of supposedly prepping a partial jaw from a block of matrix to leave it in striking relief, yet smeared with a matrix coating.  Why go to the effort of detailing around teeth, but leave a smear of matrix at the base?  Plaster/glue/matrix and fuzzy focus can look convincing.  I'm not a fan.

 

 

[pachy-pleuro-whatnot-odon]

19 minutes ago, JohnJ said:

Based on these photos, I think the first jaw is an artful fabrication.  The linear grain of the bone is uniform up to the planted teeth.  The foramina appear carved.

 

While not all Moroccan mosasaur jaws show this type of horizontal grain, these fibres are part of the natural bone and show more in some pieces than in others. Take the below specimen, for example. While not of the highest quality and having a Pluridens serpentis tooth added to what otherwise appears to be a rather natural Prognathodon sp. jaw, it does show the same fibres as are visible in OP's Jaw 1. The cross-section shows how these fibres interplay with the vascularization of the mandible as a whole, producing a pattern I've also seen in ichthyosaur jaws, for example. And while the fibres of Jaw 1 appear masked by traces of matrix in the photographs, I do believe they're there and authentic. Of course, better photographs would help clarify this.

 

 

 

19 minutes ago, JohnJ said:

I don't see the point of supposedly prepping a partial jaw from a block of matrix to leave it in striking relief, yet smeared with a matrix coating.  Why go to the effort of detailing around teeth, but leave a smear of matrix at the base?  Plaster/glue/matrix and fuzzy focus can look convincing.  I'm not a fan.

 

While I'm not fully sure I understand what you mean by "yet smeared with a matrix coating", I presume you're referring to my statement about the "glue + matrix"-paint. As you can see, the above specimen also suffers from the same phenomenon. As to why I'm so sure this is the case is because of personal experience. I once bought a Zarafasaura oceanis ischium, that, when it arrived, had broken into pieces due to careless packaging. As a result (or maybe already prior to shipping) the surface layer of glue had started to chip off to the extent that I could actually just peel it off. Most of this glue-layer was transparent so as to make it clear it was just the varnish, and didn't include any bone. However, this varnish had a yellow and in places orange tint, whereas the bone underneath was consistently white.

 

Similarly, I started prepping a mosasaur paddle last year that again looked yellow and orange on the outer surface, but showed white bone on the side extracted from the matrix - that is, that part of the fossil that had been inaccessible when the varnish was applied.

 

As to why they'd cover perfectly clean bone with a matrix paint, I can only guess at. May be it's what people expect by now and makes the fossils looks more authentic than a purely white specimen (which might appear modern, or as simply a gypsum cast). May be it's to provide the bone with a more uniform look/colour, as matrix may sometimes cling to the bone, thereby causing unnatural looking staining (to be fair, I can't see this being the reason, as the way the "matrix-paint" is often applied to me looks much more unsightly). But, to me, the most likely explanation is that it's just difficult to keep a clean brush and cleanly apply the glue/varnish to a piece of bone. As part of preparing my mosasaur paddle, for example, I consistently remove the old varnish layer, then apply a new layer of acrylic varnish to ensure that the pieces retain a uniform look. However, since the bone typically comes out looking unnaturally white with the aforementioned occasional staining where matrix could not be removed, I've taken to applying the varnish as a paint, using a paint made out of the acrylic glue and stone powder. From this I know that once your glue has touched the stone powder, it'll colour whatever you coat in the glue. But not only that, the stone powder is very hard to remove from your brush again. Thus my conclusion that where bone has been left white, the preparator paid attention to cleaning their brush before and while applying the varnish, while where bone looks yellow and/or orange a dirty brush was used...

[JohnJ]

Disparate prep raises my eyebrow.  This could be a concoction just as I described.  It's just my opinion based on the provided photos.  

 

I have some experience with mosasaurs...having personally found and cleaned three partial skulls and hundreds of various individual elements.  In full disclosure, I have never purchased a mosasaur fossil.

 

@Guns should spend some time comparing @jnoun11 's fine specimens.

[Guns]

@ThePhysicist @LordTrilobite @Troodon @Praefectus @pachy-pleuro-whatnot-odon @JohnJ  thank you so much everyone for the help and comment!!!  I will ask seller for better focus and close up photo for analyze this 2 specimen. ( I do admit that the photos i provide were a bit blur and not focus in details . sorry for that  ).

@JohnJ  thank you for the link! wow thats so eye appealing!! i will definitely spend sometime in this post.

[pachy-pleuro-whatnot-odon]

8 hours ago, JohnJ said:

Disparate prep raises my eyebrow.  This could be a concoction just as I described.  It's just my opinion based on the provided photos.  

 

I have some experience with mosasaurs...having personally found and cleaned three partial skulls and hundreds of various individual elements.  In full disclosure, I have never purchased a mosasaur fossil.

 

@Guns should spend some time comparing @jnoun11 's fine specimens.

 

True, I would also love to see some better photographs of Jaw 1 to see what's really going on there. After all my opinion too is just that, another opinion, and there certainly are things that make me wonder out the first jaw as well. I also definitely don't want to diminish your experience with mosasaurs, as what I've found out so far sounds like something I could only ever dream about, and I continuously keep finding out new things. All I'm saying is that, from my experience with both commercial and museum specimens, there's a lot of variation across the world, as well as undoubtedly across time, in both modes of preservation and ways of preparation. Material from Maastricht looks wildly different from that of Ciply, which, in itself differs markedly from what you'd find in Morocco, Kansas and Texas (where preservation differs from site to site as well). So may be the best thing to do seems indeed to advise caution on Jaw 1 and look to @jnoun11 to see what his opinion is on the matter

[Yoda]

Beginners question:

 

Jaw 1:

Teeth 1 & 3 look different to 2 & 4.

Is this normal for this type of Mosasaur ? 

(Teeth in Jaw 2 look more consistent.)

[pachy-pleuro-whatnot-odon]

6 minutes ago, Yoda said:

Beginners question:

 

Jaw 1:

Teeth 1 & 3 look different to 2 & 4.

Is this normal for this type of Mosasaur ? 

(Teeth in Jaw 2 look more consistent.)

 

That's one of the reasons to be a bit suspicious of the piece. However, I'd say that all four teeth look like they belong to the same species. If you look at just the crown (the enamelled beige/brown part), then the morphology (overall shape, curvature, ornamentation, cutting edges, that kind of thing) seems consistent between them. The main difference between tooth pairs 1 & 3 versus 2 & 4 is that the one pair has protruding roots - the white part underneath the tooth crown. This is a natural occurrence in mosasaurs and other reptiles, who change their dentition all through their lives. A new tooth starts growing below the old one, and gradually pushes the old one up and out of the jaw, subsequently taking its place. In plesiosaurs (pliosaurs to be more precise) such replacement happens in patterns, such that there's always a functional tooth next to one that might be replaced. As such, this pattern involves three teeth at a time (see Sassoon, Foffa and Marek, 2015). Unfortunately, I'm unfamiliar with the replacement patterns in mosasaurs, and thus cannot rule out that replacement would indeed take place involving only two adjacent teeth. In any case, I hope that explains why these two pairs of teeth look slightly different from one another, yet are still the same species.

 

As to why Jaw 2 appears more consistent is because we're looking at that jaw from the inside of the mouth, rather than from the outside (as with Jaw 1). As in mosasaurs the bones that make up the inside of the jaw (a skull and even a jaw is made up of various different bones all connected together) are positioned just slightly lower than those on the outside, you can see the roots more clearly from this side, giving an overall more consistent appearance.

[Guns]

@ThePhysicist @LordTrilobite @Troodon @JohnJ @pachy-pleuro-whatnot-odon @Praefectus  Hi again Y all ! I got some new photo from the seller . I hope these photo help to analyze this two jaw  

 

 Jaw number 1 : from the additional photo look like some teeth have been added to the jaw ?  still not sure about the "white'' patch area in the jaw ... restoration area ? what do you guy think ??

 

Jaw number 2 :  look ok ?  

 

 

 

thank in advance !

Guns

 

Edited August 5, 2021 by Guns
correct

[LordTrilobite]

These photos still really aren't sufficient. To make a proper assessment, much better closeups would be needed. Especially closeups of the joins between the teeth and jaw.

That being said. I think all of this looks original. Just from these photos there is no clear evidence that the teeth have been placed there afterwards. The first jaw shows some weird white areas. But I think this is just due to a bad prep job.

 

There definitely looks to be some repair on jaw 2. But I don't think jaw 1 has been tampered with at all besides the bad prep.

[pachy-pleuro-whatnot-odon]

3 minutes ago, Guns said:

Jaw number 2 :  look ok ?  

 

 

Jaw 2 still looks pretty much okay to me. You can clearly see the surface texture of the bone and even the vascularization underneath where the top layer of bone has worn away (top of third photograph). Also clearly to be seen is that the roots are connected to the bone (except for in the spot where the connecting bone is broken, second from top tooth in the first photograph), and that the teeth are connected to their roots. I have little doubt about the authenticity of this piece, although the photographs are still not good enough to provide conclusive evidence on the identification of the species. It's still halisaurine and still most likely Pluridens serpentis - I even think I see some ribbing, but can't be sure if those are photographic artefacts, just my desire to see them, or whether they're actually there.

 

13 minutes ago, Guns said:

Jaw number 1 : from the additional photo look like some teeth have been added to the jaw ?  still not sure about the "white'' patch area in the jaw ... restoration area ? what do you guy think ??

 

As Olof said, the new photographs are unfortunately still not enough to properly validate Jaw 1, however. The piece still looks rather flat to me, primarily because it's just the buccal side of the jaw without there being a lingual counterpart, but the last of the new photographs at least shows that the jaw has some curvature to it, which I would expect from a natural jaw. The second but last photograph also clarifies that there's much more variation in the shape, size and angle of the foramina in the jaw, with the sloping tear-drop shape again having me convinced these are authentic. Unfortunately, the issue with the jaw's bone texture still cannot be resolved, although I'm now having more doubts about whether or not the white part could, indeed, not be a reconstruction (I still don't think this is likely, however). What does become clear with the newest photographs, though, is that all teeth have been refitted and are not much more than that - that is, teeth, may be just with a bit of root adhering, but definitely not fully rooted. All, except for the third tooth, the one in between the two rooted ones: all the other teeth show gaps between them and the jaw bone. At least, that's how it looks to me. Still, not as bad as I originally thought, as I previously believed all teeth to have been refitted.

 

Just my 2cts.

 

May be we could ask @snolly50 to chip in here as well, though, as he's got experience re-preparing Moroccan mosasaur jaw material.

[Yoda]

4 hours ago, pachy-pleuro-whatnot-odon said:

 

That's one of the reasons to be a bit suspicious of the piece.

Thanks for the informative reply 

[Guns]

so sorry that photos were still not good.

 

@LordTrilobite and

@pachy-pleuro-whatnot-odon thank you once again for the help!!! 

 

Regard

Guns