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Teeth from the Rhaetian Bone Bed


Pleuromya

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Hello,

I collected this piece a while ago from Aust Cliff, UK. The rock is from the Rhaetian, and Severnichthys teeth are quite common from here. I was wondering if perhaps this tooth could be a small Plesiosaur tooth, or Severnichthys? This measures about 3-4mm. 

 

PXL_20220805_140417007.jpg

 

 

There's also this tooth which I was thinking could be from Hybodus? It measures about 3mm across.

 

PXL_20220805_140859391.thumb.jpg.164d00bb9734da9398753ea280dc91d3.jpg

 

Lastly, these four larger teeth, each measuring about 7-8mm. I haven't been able to find any close matches for these.

 

PXL_20220805_140523571.thumb.jpg.f8c51381a366f3ecf889ce47599e326d.jpgPXL_20220805_141500161.thumb.jpg.061a99b640dbaa5e45554882045ec42e.jpg

PXL_20220805_144710798.thumb.jpg.904fbaaf5053dfa41c1b944411d50340.jpg

PXL_20220805_150314523.thumb.jpg.b46a38b1618cb7cecef3b58fbd05133d.jpg

 

There's also some coprolites, bone fragments and what I think is the scale of Gyrolepis albertii elsewhere on the piece. 

 

PXL_20220805_135742707.thumb.jpg.41c09df213054a291253794011eefcc4.jpg

 

Thank you :)

 

 

Edited by Pleuromya
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This might be of interest:

 

(PDF) Note on the Rhaetian fish fauna from a subrosion pipe in Winterswijk (the Netherlands), with a discussion on the validity of the genus Severnichthys Storrs, 1994 (researchgate.net)

 

PXL_20220805_150314523.thumb.jpg.b46a38b1618cb7cecef3b58fbd05133d.jpg

 

I believe this is Saurichthys acuminatus. I also believe the first tooth is of the same ID.

 

On 8/5/2022 at 3:35 PM, Pleuromya said:

 

PXL_20220805_140859391.thumb.jpg.164d00bb9734da9398753ea280dc91d3.jpg

 

Rhomphaiodon minor lingual?

 

Both prior mentioned paper, as well as Microvertebrates from the basal Rhaetian Bone Bed (latest Triassic) at Aust Cliff, S.W. England - ScienceDirect could be of major use.

 

@pachy-pleuro-whatnot-odon

Isaac

 

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I think Isaac is on the right track.

 

On 8/5/2022 at 4:35 PM, Pleuromya said:

There's also this tooth which I was thinking could be from Hybodus? It measures about 3mm across.

 

PXL_20220805_140859391.thumb.jpg.164d00bb9734da9398753ea280dc91d3.jpg

 

I think your identification is correct, with the exception of Isaac's following Cross et al. (2018) that the genus name Hybodus has been superseded by that of Rhomphaiodon. That'd make this tooth, as Isaac already suggested, a R. minor. I wasn't aware of the publication before, by the way, @IsaacTheFossilMan, so thanks for sharing! It's very interesting.

 

On 8/5/2022 at 4:35 PM, Pleuromya said:

Lastly, these four larger teeth, each measuring about 7-8mm. I haven't been able to find any close matches for these.

 

PXL_20220805_140523571.thumb.jpg.f8c51381a366f3ecf889ce47599e326d.jpgPXL_20220805_141500161.thumb.jpg.061a99b640dbaa5e45554882045ec42e.jpgPXL_20220805_144710798.thumb.jpg.904fbaaf5053dfa41c1b944411d50340.jpgPXL_20220805_150314523.thumb.jpg.b46a38b1618cb7cecef3b58fbd05133d.jpg

 

These are all fish teeth as can be seen from their acrodin caps (clearest in the first specimen, but present in the second and forth, least visible in the third), as I understand it best described as a transition in the type of enameloid tissue. At Aust Cliff, the specific morphology with which this acrodin cap is connected to the lower part of the tooth is diagnostic of Severnichthys acuminatus. And while the lower part of these teeth often carry striations, this is only the case under best preservation, frequently having worn off either ante-mortem or post-depositionally (I don't really know). As with the name Hybodus above, however, Diependaal and Reumer (2021) recently reviewed the validity of S. acuminatus, finding it to belong to the genus Bigeria. Thus, these teeth should now be referred to as B. acuminatus.

 

On 8/5/2022 at 4:35 PM, Pleuromya said:

[...] and what I think is the scale of Gyrolepis albertii elsewhere on the piece.

 

That seems a likely culprit for a fish scale included in this matrix.

 

On 8/5/2022 at 4:35 PM, Pleuromya said:

I was wondering if perhaps this tooth could be a small Plesiosaur tooth, or Severnichthys? This measures about 3-4mm. 

 

PXL_20220805_140417007.jpg

 

Based on this single photograph and with the tooth still largely embedded in matrix, I find it hard to say. Of course plesiosaur teeth are found at that location, especially the rhomealosaurid Eurycleidus arcuatus, which does have strong striations. However, those striations, in the specimens I've seen, are only found on the lingual side of the tooth, where they, moreover, run the full apicobasal height of it. The tooth may still be plesiosaurian, especially in absence of a clear acrodin cap. But in order to establish that, the tooth would need to be freed up further, and, to be honest, I doubt that it'll turn out plesiosaurian even than. Considering the restricted location of the striae on this tooth and what looks to be a carina on the bottom left of the tooth - which is a feature absent in plesiosaur teeth, but one present in B. acuminatus - I rather suspect this to be another Birgeria acuminatus tooth.

 

In any case, if all of these specimens come from the same piece of matrix, it's an especially rich sample! Nice find! :D

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

I wasn't aware of the publication before, by the way, @IsaacTheFossilMan, so thanks for sharing! It's very interesting.

 

Of course, my friend!

 

I wasn't aware of Diependaal and Reumer (2021) reviewing Saurichthys a. to be Birgeria, so, thank you

 

It's nice to be validated by such an awesome palaeontologist as you, my good friend!

Edited by IsaacTheFossilMan
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~ Isaac; www.isaactfm.com 

 

"Don't move! He can't see us if we don't move!" - Alan Grant

 

Come to the spring that is The Fossil Forum, where the stream of warmth and knowledge never runs dry.

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11 hours ago, IsaacTheFossilMan said:

This might be of interest:

 

(PDF) Note on the Rhaetian fish fauna from a subrosion pipe in Winterswijk (the Netherlands), with a discussion on the validity of the genus Severnichthys Storrs, 1994 (researchgate.net)

 

PXL_20220805_150314523.thumb.jpg.b46a38b1618cb7cecef3b58fbd05133d.jpg

 

I believe this is Saurichthys acuminatus. I also believe the first tooth is of the same ID.

 

 

Rhomphaiodon minor lingual?

 

Both prior mentioned paper, as well as Microvertebrates from the basal Rhaetian Bone Bed (latest Triassic) at Aust Cliff, S.W. England - ScienceDirect could be of major use.

 

@pachy-pleuro-whatnot-odon

Isaac

 

Thank you. :)

The links look great, I have came across the paper about the Microvertebrates before,  although due to having to buy it, I have only had some of the pictures to compare to. I haven't seen the first one, but it looks like it will be very useful at helping identifying some of my other finds.

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9 minutes ago, Pleuromya said:

Thank you. :)

The links look great, I have came across the paper about the Microvertebrates before,  although due to having to buy it, I have only had some of the pictures to compare to. I haven't seen the first one, but it looks like it will be very useful at helping identifying some of my other finds.

 

The first one is very helpful, I've found! Happy hunting, and congrats on a beautiful piece.

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~ Isaac; www.isaactfm.com 

 

"Don't move! He can't see us if we don't move!" - Alan Grant

 

Come to the spring that is The Fossil Forum, where the stream of warmth and knowledge never runs dry.

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

I think Isaac is on the right track.

 

 

I think your identification is correct, with the exception of Isaac's following Cross et al. (2018) that the genus name Hybodus has been superseded by that of Rhomphaiodon. That'd make this tooth, as Isaac already suggested, a R. minor. I wasn't aware of the publication before, by the way, @IsaacTheFossilMan, so thanks for sharing! It's very interesting.

 

 

These are all fish teeth as can be seen from their acrodin caps (clearest in the first specimen, but present in the second and forth, least visible in the third), as I understand it best described as a transition in the type of enameloid tissue. At Aust Cliff, the specific morphology with which this acrodin cap is connected to the lower part of the tooth is diagnostic of Severnichthys acuminatus. And while the lower part of these teeth often carry striations, this is only the case under best preservation, frequently having worn off either ante-mortem or post-depositionally (I don't really know). As with the name Hybodus above, however, Diependaal and Reumer (2021) recently reviewed the validity of S. acuminatus, finding it to belong to the genus Bigeria. Thus, these teeth should now be referred to as B. acuminatus.

 

 

That seems a likely culprit for a fish scale included in this matrix.

 

 

Based on this single photograph and with the tooth still largely embedded in matrix, I find it hard to say. Of course plesiosaur teeth are found at that location, especially the rhomealosaurid Eurycleidus arcuatus, which does have strong striations. However, those striations, in the specimens I've seen, are only found on the lingual side of the tooth, where they, moreover, run the full apicobasal height of it. The tooth may still be plesiosaurian, especially in absence of a clear acrodin cap. But in order to establish that, the tooth would need to be freed up further, and, to be honest, I doubt that it'll turn out plesiosaurian even than. Considering the restricted location of the striae on this tooth and what looks to be a carina on the bottom left of the tooth - which is a feature absent in plesiosaur teeth, but one present in B. acuminatus - I rather suspect this to be another Birgeria acuminatus tooth.

 

In any case, if all of these specimens come from the same piece of matrix, it's an especially rich sample! Nice find! :D

Thank you :)

I wasn't aware that S. acuminatus had been reviewed either, so I will have to update my labels. :)

 

I probably won't risk freeing up the striated tooth, as it's so small that I wouldn't want to risk breaking it, particularly if it is unlikely to be plesiosaurian.

 

I forgot to mention that two of the larger fish teeth are not from the same specimen,  but there are many other teeth which I think are also Birgeria acuminatus in it. 

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7 minutes ago, IsaacTheFossilMan said:

 

The first one is very helpful, I've found! Happy hunting, and congrats on a beautiful piece.

Thank you :)

Aust is one of my favourite sites.

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53 minutes ago, Pleuromya said:

Thank you :)

Aust is one of my favourite sites.

 

I am actually yet to visit it, despite living so close by... I keep thinking of planning a trip, but never get around to doing it... :(

~ Isaac; www.isaactfm.com 

 

"Don't move! He can't see us if we don't move!" - Alan Grant

 

Come to the spring that is The Fossil Forum, where the stream of warmth and knowledge never runs dry.

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10 minutes ago, IsaacTheFossilMan said:

 

I am actually yet to visit it, despite living so close by... I keep thinking of planning a trip, but never get around to doing it... :(

I have only been a few times, last time I visited, I found much more material on the more overgrown side of the beach, where less people were, but it was quite difficult to access as the mud around the Severn Bridge was really thick. 

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4 hours ago, Pleuromya said:

I have only been a few times, last time I visited, I found much more material on the more overgrown side of the beach, where less people were, but it was quite difficult to access as the mud around the Severn Bridge was really thick. 

 

Desperate times call for... The good ol' British welly! 

 

You will have to show me around sometime, my friend! ;)

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~ Isaac; www.isaactfm.com 

 

"Don't move! He can't see us if we don't move!" - Alan Grant

 

Come to the spring that is The Fossil Forum, where the stream of warmth and knowledge never runs dry.

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3 minutes ago, IsaacTheFossilMan said:

 

Desperate times call for... The good ol' British welly! 

 

You will have to show me around sometime, my friend! ;)

That would be good, I would definitely recommend wellies. :)

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13 hours ago, Pleuromya said:

Thank you. :)

The links look great, I have came across the paper about the Microvertebrates before,  although due to having to buy it, I have only had some of the pictures to compare to. I haven't seen the first one, but it looks like it will be very useful at helping identifying some of my other finds.

 

As a tip, whenever you encounter a paywalled article, it always pays to search online to see if you can find a way to access the article for free. It's not uncommon that paywalled articles to show up on ResearchGate - as is the case with the microvertebrate-article, in this case - or other third-party sites ;)

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'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett

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

 

As a tip, whenever you encounter a paywalled article, it always pays to search online to see if you can find a way to access the article for free. It's not uncommon that paywalled articles to show up on ResearchGate - as is the case with the microvertebrate-article, in this case - or other third-party sites ;)

Thank you, that's really helpful. :)

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