Plesiosaur tooth/teeth?

[Still_human]

This kind of tooth surface, with the ridges, isn’t that for the most part, not a common plesiosaur feature? This is from Lyme Regis....what would you all think? 

[Tidgy's Dad]

Ichthyosaur teeth from the area also have these ridges, but the plesiosaur ones from Lyme Regis are a) rather rare and b ) usually with much finer striations in my experience.

I think your specimens are probably ichthyosaur. 

[Pterygotus]

Plesiosaur teeth tend to be much thinner than ichthyosaur teeth. The ichthyosaur teeth do have ridges at Lyme like @Tidgy's Dad said. 2 looks plesiosaur but 1 and 3 look ichthyosaur. However, I’m not completely sure on 2 because that piece of matrix adhering seems to be messing with my mind as I’m not how much tooth is under it .

[fossil_sea_urchin]

Ichthyosaur teeth are straight with large striations, this is curved with fine striations which lead me to believe this is probably a plesiosaur tooth but is very unlikely to be Ichthyosaur tooth. @Pterygotus all the pictures are one tooth how did you come to your identification other than the facts you've posted? As you mentioned @Still_human the tooth is unusual and appears to be of a plesiosaur of great size, possibly an early form edging towards pliosaurs, either way very nice

[Pterygotus]

6 minutes ago, fossil_sea_urchin said:

Ichthyosaur teeth are straight with large striations, this is curved with fine striations which lead me to believe this is probably a plesiosaur tooth but is very unlikely to be Ichthyosaur tooth. @Pterygotus all the pictures are one tooth how did you come to your identification other than the facts you've posted?

Not all ichthyosaur teeth are straight. Below is a picture of teeth of ichthyosaurus communis. Only just realised that they are in fact the same teeth. Got confused because @Still_human said ‘teeth’ as well . Like I stated above, that piece of matrix on the side is messing with my mind. Like @Tidgy's Dad stated above, plesiosaur teeth are considerably rarer than ichthyosaur teeth and the seller seems to be listing an unusually large amount of them.

[fossil_sea_urchin]

1 minute ago, Pterygotus said:

Not all ichthyosaur teeth are straight. Below is a picture of teeth of ichthyosaurus communis. Only just realised that they are in fact the same teeth. Got confused because @Still_human said ‘teeth’ as well . Like I stated above, that piece of matrix on the side is messing with my mind. Like @Tidgy's Dad stated above, plesiosaur teeth are considerably rarer than ichthyosaur teeth and the seller seems to be listing an unusually large amount of them.

The striations become more spread out towards the tip unlike on the teeth of Ichthyosaurus communis.

[Tidgy's Dad]

Yes, Ichthyosaur teeth can be curved, straight, sort of triangular, all sorts at Lyme Regis. 

I found lots, back in the day, but only one plesiosaur tooth. 

The striations on the slim, curved plesiosaur teeth are much finer than this. 

I'm pretty certain this is ichthyosaur.

 

[Pterygotus]

18 minutes ago, Tidgy's Dad said:

Yes, Ichthyosaur teeth can be curved, straight, sort of triangular, all sorts at Lyme Regis. 

I found lots, back in the day, but only one plesiosaur tooth. 

The striations on the slim, curved plesiosaur teeth are much finer than this. 

I'm pretty certain this is ichthyosaur.

 

Still haven’t even found a vertebra yet . I have to base my ID’s off tiny ones I’ve found at Aust and ones in museums and collections .

[Pterygotus]

Just now, Pterygotus said:

Still haven’t even found a vertebra yet . I have to base my ID’s off ones I’ve found at Aust and ones in museums and collections .

I had a chance after two large storms but spent 2 hours at Lyme trying to break a fossil out of a metre long piece of rock.

[Welsh Wizard]

Looking at the curve of the tooth, I would say it’s from a plesiosaur.

 

N

[Still_human]

23 hours ago, fossil_sea_urchin said:

Ichthyosaur teeth are straight with large striations, this is curved with fine striations which lead me to believe this is probably a plesiosaur tooth but is very unlikely to be Ichthyosaur tooth. @Pterygotus all the pictures are one tooth how did you come to your identification other than the facts you've posted? As you mentioned @Still_human the tooth is unusual and appears to be of a plesiosaur of great size, possibly an early form edging towards pliosaurs, either way very nice

That’s what I was wondering. I know pliosaurs commonly have the tooth striations like this, so my mind immediately went to pliosaur

[Still_human]

23 hours ago, Tidgy's Dad said:

Yes, Ichthyosaur teeth can be curved, straight, sort of triangular, all sorts at Lyme Regis. 

I found lots, back in the day, but only one plesiosaur tooth. 

The striations on the slim, curved plesiosaur teeth are much finer than this. 

I'm pretty certain this is ichthyosaur.

 

How about opposed to pliosaur? I’m not sure why, I’ll have to ask, but the person, who is an ichthyosaur collector, thinks this is not an ichthyosaur, but a plesi(or plio).

[Tidgy's Dad]

1 hour ago, Still_human said:

How about opposed to pliosaur? I’m not sure why, I’ll have to ask, but the person, who is an ichthyosaur collector, thinks this is not an ichthyosaur, but a plesi(or plio).

I have a little experience, but am by no means an expert. 

I still say icthyosaur from my own studies, but am often wrong.

In my limited experience, people often  want it to be a plesiosaur because it's rarer, but it's nearly always ichthyosuar 

I may be wrong, but i see no definite plesiosaur features here (from Lyme Regis specimens that I know of)  

Pliosaur is possible from Lyme Regis, but do you really think this fits? 

As I keep saying, I am no expert, but have collected there many times 

I would say this is ichthyosaursus , but am open to decent reasons why it isn't .

Not what someone wants it to be. 

[pachy-pleuro-whatnot-odon]

On 2/23/2020 at 9:17 PM, fossil_sea_urchin said:

Ichthyosaur teeth are straight with large striations, this is curved with fine striations which lead me to believe this is probably a plesiosaur tooth but is very unlikely to be Ichthyosaur tooth. @Pterygotus all the pictures are one tooth how did you come to your identification other than the facts you've posted? As you mentioned @Still_human the tooth is unusual and appears to be of a plesiosaur of great size, possibly an early form edging towards pliosaurs, either way very nice

On 2/24/2020 at 9:04 PM, Still_human said:

That’s what I was wondering. I know pliosaurs commonly have the tooth striations like this, so my mind immediately went to pliosaur

 

I feel like I should add my 2cts in this discussion, since this specific specimen has since found its way into my collection - as have various similar teeth offered by the same seller. And though I too was originally surprised by the amount of plesiosaur material this particular seller had on offer (plesiosaur finds not being all that common in the Lyme Bay area, as @Tidgy's Dad pointed out), the material looked good to me, being clearly identifiable as plesiosaur - i.e. various more recognizable plesiosaur teeth, vertebrae, paddle bones, and even an occasional podial.

 

It would also be good to keep in mind that we don't know over what amount of time these items were collected: the collection could have been built up over several years prior to sale. Alternatively, a full or partial skeleton may have eroded out of the cliffs only to be smashed to bits by the rocks and waves, so that only a lot of similar, yet more fragmentary, material could be found. For me, this seems the most likely scenario, as multiple of the same types of teeth were all offered around the same time. The same has happened to me once as a child, when searching in Lyme Regis: in one day I found a ton of small rib-fragments of what may have been a fish, but may very well also have been a juvenile ichthyosaur, judging from the piece of jaw-bone my mother found the same day in the same area.

 

For me the first clue that the above tooth indeed concerns a plesiosaur tooth was that the striations are clearly marked on the lingual side of the tooth, but are absent from the labial side. As far as I know, this is not a condition found in ichthyosaur teeth, which either have them all around or, in infrequent cases, not at all. The striations, moreover, are more sharply defined than those typically found on ichthyosaur teeth. As one TFF-member put it, they were more "squarish" rather than rounded. That is, this was not a case of the regular plicidentine condition so typical for ichthyosaur teeth.

 

The second clue was in comparing them with similar specimens that the seller had on offer, which showed the roots as smooth and round in cross-section, rather than bulbous and somewhat square with optional folds, as is the case with ichthyosaurs. This is an indication of how these teeth would have fit in the jaw, with the roots of ichthyosaurs facilitating placement along a groove in ichthyosaur jaws (I believe this is considered a variation on the pleurodont dentition). The roots I was seeing, however, were clearly indicative of a thecodont dentition, meaning they would have set in individual alveoli, or tooth-sockets. This dental condition occurs in mammals, dinosaurs and crocodilians, as well as plesiosaurs. With the first two of these group falling out of context and no carinae being present on the teeth (ruling out croc), these had to be plesiosaur teeth.

 

What further convinced me about the plesiosaurian nature of these teeth, and makes me indeed consider them as likely candidates for very early pliosaur teeth, is the fact that they're very similar to a tooth I managed to acquire from Wimereux, said to date to the tithonian (very latest) Jurassic. That tooth is very similar in general appearance (though thinner and taller) to the Liopleurodon tooth figured by Sven Sachs here (image below) and classified as Liopleurodon in other places as well. Now tithonian would be too late for Liopleurodon as such, but it could be that the strata from which the tooth derives has been identified wrongly, or the tooth belongs to another plesiosaurid. However, what becomes clear when checking The Paleontology Database is that the only plesiosaurians reported for that region seem to be pliosaurs, most with uncertain attribution, yet all from the Kimmeridgian - a time when Liopleurodon was still around. The only other plesiosaur reported from the area is Cryptoclidus, which, however, has smooth teeth. So pliosaur that tooth is, cf. Liopleurodon. In fact, there's a very similar tooth posted on this forum, albeit Cretaceous and from Texas. But please note Mike from North Queensland's response, as he seems rather knowledgable on marine reptiles, from what I've read on the forum: "nice pliosaur tooth".

 

How this all comes together is that I believe the tooth discussed here, as the similar pieces I acquired from the same seller, are definitely plesiosaurian in nature, and very probably early pliosaurid. Seeing as the most prominent of them around at the time were rhomaleosaurids and these teeth show many similarities to Eurycleidus arcuatis, I currently have this set of teeth marked down as Rhomaleosauridae indet.

Cheers,
Alexander.

[Mike from North Queensland]

I will defer to those who collect in the area for a better confirmation as I have only one species of ichthyosaur from my collecting area to compare against.

The stirations look like what I would expect from a pliosaur. the root is round in shape as in pliosaur.

Ichthyosaurs from my area tend to be squarer as they grow more from a long continuous slot in the jaw rather than as a single erupted tooth.

 

Mike

[Planko]

Ok, I am no expert by any means. Even worse at teeth. Could not help but to think I have seen something similar to that tooth. It was a spinosaurus tooth. Then I looked to see if they had any relatives that might of marched around the England area eating stuff. And there is one that might work: Baryonyx. Just a thought. 

[Troodon]

48 minutes ago, Planko said:

Ok, I am no expert by any means. Even worse at teeth. Could not help but to think I have seen something similar to that tooth. It was a spinosaurus tooth. Then I looked to see if they had any relatives that might of marched around the England area eating stuff. And there is one that might work: Baryonyx. Just a thought. 

A ‘typical’ baryonychine tooth possesses 6-7 ridges on either side or both so this one looks to dense to be one but a good idea  lots of similarities

[pachy-pleuro-whatnot-odon]

Just bumped into another very similar tooth here on TFF, for those interested