Fish tooth from the Triassic of Bulgaria, Anisian

[Dimitris]

Hello!

I am assisting a friend identifying this tooth.

He found it in Anisian limestone and so far has not managed to find any further information, since there is not a single publication.

The environment is marine, since there are shell imprints, without any shell preserved, so he assumes it belongs to a fish.

 

Another friend said that it might even belong to a reptilian and the teeth have crushing form.

It's size is around that of a dime, maybe slightly larger.

Any help would be appreciated!

[pachy-pleuro-whatnot-odon]

Definitely not reptilian, but indeed the mouth plate of a fish. Your friend is probably thinking of placodontia, which do have tribodont/crushing teeth, but which teeth are much bigger, and arranged in a V-shape in their mouths:

 

Overview of placodont dentition and cranial shape, at the Zoological and Paleontological Collections of the University of Zurich

 

 

Placodus gigas (left) and Placochelys placodonta (right) dentition at the Naturmuseum Senckenberg in Frankfurt

 

Your specimen is much more similar to the tooth batteries of Bobasatrania scutata, such as the specimen below from Zwingelhausen in Germany:

 

 

 

And like this specimen from the Muschelkalk Museum:

 

 

As your example appears to have a bone base, however, it's more likely that your fossil does not belong to B. scutata, but instead can be attributed to Colobodus sp. (ibid.), known from the Muschelkalk and Lower Keuper/Middle Triassic. That's just a best guess, however, as I'm really not too familiar with fish... May be members like @sander or @Pemphix would have more to add.

 

[sander]

First of all, this is not my speciality, so I am not sure on this.

I think it might be a tooth palate of a colobodus-like fish: 

https://www.researchgate.net/publication/285582931_BOTTCHER_R_2015_8_Fische_des_Lettenkeupers_-_In_HAGDORN_H_SCHOCH_R_SCHWEIGERT_G_eds_Der_Lettenkeuper_-_Ein_Fenster_in_die_Zeit_vor_den_Dinosauriern_-_Palaeodiversity_Sonderband_141-202

 

But when I think outside the box (really far-fetched) it could also be a part of a shark spine:

https://core.ac.uk/download/pdf/18225978.pdf

 

Better to wait until a triassic fish specialist has reacted here though.

Kind regards,

Sander

Edited October 26, 2021 by sander

[pachy-pleuro-whatnot-odon]

20 hours ago, sander said:

But when I think outside the box (really far-fetched) it could also be a part of a shark spine

 

I hadn't really considered this, as 1) the close-up of the teeth clearly shows similar patterns of striations as do the shell-crushing teeth of both crocodiles and mosasaurs, and 2) the bone on which the teeth sit is concave rather than convex - together leaving little doubt in my mind that this is the tooth battery of a fish. But, yeah, you're right: there it's a certain resemblance with some shark fin spines. Kudos for thinking out of the box line that! 

[Dimitris]

On 10/26/2021 at 12:33 PM, pachy-pleuro-whatnot-odon said:

Your specimen is much more similar to the tooth batteries of Bobasatrania scutata, such as the specimen below from Zwingelhausen in Germany:

 

 

 

And like this specimen from the Muschelkalk Museum:

 

 

As your example appears to have a bone base, however, it's more likely that your fossil does not belong to B. scutata, but instead can be attributed to Colobodus sp. (ibid.), known from the Muschelkalk and Lower Keuper/Middle Triassic. That's just a best guess, however, as I'm really not too familiar with fish... May be members like @sander or @Pemphix would have more to add.

 

 

Really hard to tell. The first set of teeth of scutata resemble a lot in terms of shape, but they are much more in quantity.

As per the second sample, I don't understand where to look for the bonny structure.

 

22 hours ago, sander said:

First of all, this is not my speciality, so I am not sure on this.

I think it might be a tooth palate of a colobodus-like fish: 

https://www.researchgate.net/publication/285582931_BOTTCHER_R_2015_8_Fische_des_Lettenkeupers_-_In_HAGDORN_H_SCHOCH_R_SCHWEIGERT_G_eds_Der_Lettenkeuper_-_Ein_Fenster_in_die_Zeit_vor_den_Dinosauriern_-_Palaeodiversity_Sonderband_141-202

 

This one looks possible.

 

22 hours ago, sander said:

 

But when I think outside the box (really far-fetched) it could also be a part of a shark spine:

https://core.ac.uk/download/pdf/18225978.pdf

 

Rhomaleodus has been found in Bulgaria, though I cannot find any article showing its spine. Yet again, these sharks belong to chondrichthyes. Wouldn't that make the fossilization of skeletal part (which is not even skeleton) impossible?

[R0b]

Maybe an alternative from this topic, an amphibian.

 

 

[pachy-pleuro-whatnot-odon]

3 hours ago, R0b said:

Maybe an alternative from this topic, an amphibian.

 

Based on the images there, hard to exclude this. But I haven't seen any temnospondyl material like that come out of the German Muschelkalk yet (not that I'm extremely savvy on either the Muschelkalk or temnospondyl amphibians, though). I'm therefore inclined to stick with the fish mouth plate interpretation, which seems a better fit, both geographically and stratigraphically...

 

On 10/27/2021 at 6:06 PM, Dimitris said:

Really hard to tell. The first set of teeth of scutata resemble a lot in terms of shape, but they are much more in quantity.

As per the second sample, I don't understand where to look for the bonny structure.

 

I wouldn't get too hung up on quantity, as is shown from the two specimens I posted, since the density of the one specimen there is also much higher than that of the other (this is actually one of the main reasons I posted the second sample, since it illustrates tooth densities may differ).

 

As to the boney structure: the teeth in your example are clearly not just lying directly on the rock/matrix, but on a small black plate. This is, in fact, bone, namely the mouth plate of the fish to which the teeth belong. You won't see that in B. scutata, which teeth have ended up lying directly on the matrix (as can most clearly be seen in the second example I provided)...

 

Quote

Rhomaleodus has been found in Bulgaria, though I cannot find any article showing its spine. Yet again, these sharks belong to chondrichthyes. Wouldn't that make the fossilization of skeletal part (which is not even skeleton) impossible?

 

While it's generally true that the cartiligenous doesn't easily fossilised, shark skeletons do occasionally preserve under exceptional circumstances. In addition, certain bones seem to have a greater of being preserved than others, which includes the fin spines, vertebrae, and, I understand, even nose tips (have a look amongst the older threads on this forum).

 

Below are some examples of exceptionally preserved sharks:

 

Hybodont shark with a stomach full of belemnite rostra at the Urweltmuseum Hauff in Holzmaden (Toarcian)

 

Huge hybodont shark from the Posidonia Shale at the Museum am Löwentor, Stuttgart (Toarcian)

 

A spectacular Hybodus obtusus from the Solnhofen quarries at a temporary exhibit at the Sauriermuseum Aathal (Tithonian)

 

An astoundingly well-preserved specimen of Carcharocles megalodon from the Aguada de Lomas formation of Arequipa in Peru at the same temporary exhibit (Tortonian)

Edited October 28, 2021 by pachy-pleuro-whatnot-odon

[Dimitris]

15 hours ago, R0b said:

Maybe an alternative from this topic, an amphibian.

 

 

 

Crossed my mind. Just for the reference, the environment of the sea floor resembles marine.

There are imprints of shells similar to Chlamys sp. or Daonella sp.

 

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

 

Based on the images there, hard to exclude this. But I haven't seen any temnospondyl material like that come out of the German Muschelkalk yet (not that I'm extremely savvy on either the Muschelkalk or temnospondyl amphibians, though). I'm therefore inclined to stick with the fish mouth plate interpretation, which seems a better fit, both geographically and stratigraphically...

 

In the middle Triassic of Bulgaria, bone material has been found by the same person. I  have to ask though if it was the same locality and formation.

 

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

 

I wouldn't get too hung up on quantity, as is shown from the two specimens I posted, since the density of the one specimen there is also much higher than that of the other (this is actually one of the main reasons I posted the second sample, since it illustrates tooth densities may differ).

 

Indeed, density is what matters and the patern,  shape and angles of each individual tooth.

 

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

As to the boney structure: the teeth in your example are clearly not just lying directly on the rock/matrix, but on a small black plate. This is, in fact, bone, namely the mouth plate of the fish to which the teeth belong. You won't see that in B. scutata, which teeth have ended up lying directly on the matrix (as can most clearly be seen in the second example I provided)...

 

To be honest, I haven't seen the sample in person. Moreover, I have zero experience with such material.

 

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

 

While it's generally true that the cartiligenous doesn't easily fossilised, shark skeletons do occasionally preserve under exceptional circumstances. In addition, certain bones seem to have a greater of being preserved than others, which includes the fin spines, vertebrae, and, I understand, even nose tips (have a look amongst the older threads on this forum).

 

Below are some examples of exceptionally preserved sharks:

 

Hybodont shark with a stomach full of belemnite rostra at the Urweltmuseum Hauff in Holzmaden (Toarcian)

 

^ This is truly amazing. 

[Pemphix]

Sorry not to answer earlier, but had a lot of job to do.

For me that is pretty clear a mouth-plate of Colobodus sp., no Bobasatrania mouth-plate and no fragment of shark-spine and no amphibian plate of any kind.

Key for the determination (see BOETTCHER 2015 in Paleodiversity, Special Issue "Lettenkeuper"): the sublime warts in the middle of each teeth (see microscopic pictures above). This is typical for teeth of Colobodus and NOT for Bobasatrania (missing warts) and -like already said- Bobasatrania usually do not have a bone base of the "mouth-plate" (nevertheless, i own a piece with the bone base, so that is/might be not a strong determination criteria). Furthermore, shark-spines do not have those warts, too.

In rare cases, amphibian remains can be found in Anisian deposits (i have a pretty complete Plagiosternum clavicle from the uppermost Muschelkalk), but even those have no such warts in the middle of the pustules on the surface of the dermal (or other) plates.