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pachy-pleuro-whatnot-odon

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Hi everyone,

 

Recently, while researching the morphology of machimosaurid crocodile teeth, I bumped into the below specimen, identified as Machimosaurus hugii (presumably based on its size). And although I can't confirm the specific name, I'm confident the referral to Machimosaurus is correct.

 

5ffb48549972d_MachimosaurushugiitoothonmatrixLourinhFormationPortugal02.thumb.jpg.7579d92ddebf07976b6b9c1e4dc7aa15.jpg

 

When taking a closer look at the tooth's striations, however, I noticed not all of them actually run the whole apicobasal length of the tooth as I expected. And although some striations have undoubtedly been terminated and/or interrupted by wear, I was more genetically wondering if striations not running the full apicobasal length of the tooth is a know characteristic of crocodile teeth.

 

For I'm only familiar with teeth that are either entirely smooth, or that have fine striations on one or both sides of the tooth, where only those striations that run into one of the tooth's carinae may be truncated before reaching the full apicobasal length of the tooth. That having been said, though, I can imagine crocodilian dental ornamentation being more varied, with different patterns of organisation in their striations, as Madzia (2016, A reappraisal of Polyptychodon (Plesiosauria) from the Cretaceous of England), in an annotation with his figure 8 illustrating pliosaurid tooth crown morphologies following Tarlo (1960) (reproduced below), observes that the teeth with the most striae, previously referred to Simolestes nowackianus, are now considered Machimosaurus nowackianus. And with the great variation of expression in striations on pliosaurian teeth, I don't think it would be such a leap to assume the same for this species of teleosaur...

 

peerj-04-1998-g008.jpg.03466509aecf45566c9aaf6cbf605c1e.jpg

 

So, my question is: are striations on crocodilian teeth as variable as they are amongst pliosaurs? Can individual striae end prior to stretching the full apicobasal length of the tooth, and, if so, in which clades or under what conditions? Do crocodilian teeth exhibit patterns of striations of interchanging lengths (e.g., short-long-short)?

 

Thanks for your help!

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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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Could I ask your opinions, @Jesuslover340, as the author of the excellent guide on alligator vs. crocodile tooth identification, and @caterpillar, for your general knowledge on crocodilians?

'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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Thanks! And no need to apologize! I might not get through it as fast as in another language, but it seems like a very interesting article to read.

 

I'll see if I can report my findings back here afterwards. Though that might take a while, as I've got quite a bit of literature still lined up :P

'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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Hmmm....good question. Variable striations,  absolutely, but variable striations with some terminating prematurely I myself have not come across :unsure: I checked my collection and even modern C. porosus skulls and those with striations all run the full apicobasal length, but of course, take that with a grain of sand as my collection is by no means comprehensive. 

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"Let us therefore follow after the things which make for peace, and things wherewith one may edify another."
-Romans 14:19

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Thanks for sharing your insights! I guess I'll just have to check the above article to find out whether that answers my question ;)

 

Thing is, I received four marine reptile teeth before Christmas that were supposed to be plesiosaurian teeth. But when I received them, it turned out they've got carinae, and look much more like teleosaurid crocodilian teeth. However, certain characteristics don't match up with that hypothesis either - not to mention one of them comes from Lavernock (the others are Oxford Clay from the Peterborough area), from the Terminal Triassic to Earliest Jurassic, and thus from a time that knows a paucity (if not total lack) of thalattosuchians. I took some photographs and still intend to post them on the Fossil ID board, but wanted to educate myself a bit mor beforehand (will refer to it here when I do, if needed).

 

One of the teeth seemed to lack carinae, and has a distinct pattern of striations that seems to match that of Peloneustes philarchus, so that I initially identified it as such - or possibly an ancestral species, as it dates to the Callovian Jurassic, a time from which P. philarchus is not known. However, even recently re-examining the tooth, I spotted something that looks a lot like a carina (though it's hard to say for sure with the tip missing), and have now started doubting again, especially as the tooth looks nothing like the other tooth in my collection I've currently got marked down as P. philarchus from Peterborough. Below is a photograph:

 

Plessy2021.jpg.f98371756f138a649c95e0fa2bebab6e.jpg

 

And, for comparison, a schematic drawing of pliosaur tooth morphotypes following Tarlo's 1960 A review of Upper Jurassic pliosaurs, with the type attributed to Peloneustes to the right (F).

 

peerj-04-1998-g008.jpg.03466509aecf45566c9aaf6cbf605c1e.jpg

 

And just for good measures, the two others from the same batch (the fourth, as said, comes from a different site) - though the last image, unfortunately, isn't sharp enough to show the striations on that tooth...

 

Plessy2018.jpg.23df61dcd54255bf6b154e9b09af3163.jpgPlessy2059.jpg.57a4acedf12a7218097bfaf3862d0271.jpg

'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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  • 3 weeks later...
On 1/16/2021 at 6:34 PM, pachy-pleuro-whatnot-odon said:

Plessy2021.jpg.f98371756f138a649c95e0fa2bebab6e.jpg

Hi @paulgdls,

I think the above tooth might be either Peloneustes philarchus. Can I ask you for your opinion? What do you think? Does this look like a small pliosaurian tooth to you - and does it match Peloneustes' ornamental morphology? It seems very close to what Tarlo (1960) describes...

'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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  • 2 months later...

Although the ornamentation of the teeth under discussion in this thread mainly focussed on the differentiation between teleosauroid and pliosaurian teeth, I just wanted to point to @PointyKnight's excellent overview and description of metriorhynchid thalattosuchian teeth from the Oxford Clay:

 

 

Edited by pachy-pleuro-whatnot-odon
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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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Another interesting thread on a marine crocodile tooth, which demonstrates:

 

  1. that striae on marine crocodile teeth can be as bold as in certain pliosaur species;
  2. that the density of striations may differ lingually and labially;
  3. that presence of carinae may vary along the length of the jaw, with anterior teeth showing carinae more prominently than posterior ones; and
  4. that striae on machimosaurid teeth may bifurcate and reticulate as much as not span the full apicobasal height of a tooth (either starting above the base or terminating before the apex).

 

'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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  • 1 year later...

When I started this thread almost two years ago, I did so because I'd been wondering about three teeth in particular. I've since seen many more teleosaurid, pliosaur and plesiosaur teeth, and have thus been able to answer my own question as to what these teeth are, in the sense that they are indeed marine crocodile teeth. For reference, I posted photographs of two of these teeth below (taking anywhere near quality photographs of them was a real challenge, as the teeth are not only small, but the light needs to be balanced and refracted just right in order for the striae to show up; at one point I gave up, but, in doing do, have newfound respect for those who are actually able to take quality photographs of such teeth!). Both are Teleosauridae indet. from the Oxford Clay and both were originally misidentified as plesiosaur. In fact, they're the same teeth as in the post above.

 

Tooth 1

1024609149_Teleosauridtooth1lingual.jpg.0b9a223b798600f1f96e42afd94800b7.jpg1881413094_Teleosauridtooth1mesiodistal1.jpg.153918c3741f34ba3dadee5f2b743182.jpg812802773_Teleosauridtooth1mesiodistal2.jpg.d8a6d2f8c55cc2f8c78991f006d40970.jpg776299517_Teleosauridtooth1labial1.jpg.d52b545821b44e4eb39b374de8e31d7d.jpg634619932_Teleosauridtooth1labial2.jpg.6b63b39f18b3de561171cb920cfc945c.jpg

 

 

Tooth 2

957936565_Teleosauridtooth2labial1.jpg.8de65444941e3d4613516284033e7530.jpg539969620_Teleosauridtooth2labial2.jpg.de129803803d61ce3738589b7b4cd05a.jpg997621909_Teleosauridtooth2lingual.jpg.a19c501bd294a8d89bd4ac1c1a1685d1.jpg1677202126_Teleosauridtooth2mesiodistal1.thumb.jpg.b21462eb8583f4710382bd24fba9b814.jpg875792847_Teleosauridtooth2mesiodistal2.thumb.jpg.d6c90ef138bc5fbc163c2dd52dca49c3.jpg1282807139_Teleosauridtooth2mesiodistal3.thumb.jpg.975eea84f2fd04a7f607d5f07afb7a17.jpg1904409446_Teleosauridtooth2mesiodistal4.thumb.jpg.fcfbe401ae4db2583f9e9bff213fc2a6.jpg

 

 

I'll come back to post on the third teeth later, as that particular tooth is said to have come from a site that makes its identification somewhat problematic...

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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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  • 1 month later...

So here's the final tooth I originally started this thread for. It's identification is problematic, as it's said to come from Penarth, in Wales, where exposed strata date to both the Triassic and very earliest Jurassic (Hettangian).

 

penarth.jpg.59e68997baa0acabb2218b28c45898e6.jpg

(source)

 

I'd definitely say the features of this tooth are teleosaurid, both in terms of the ornamentation/striae and carinae, as well as banding. However, teleosaurids aren't know until much later in the Jurassic, first being recorded in the Toarcian, towards the end of the Early Jurassic, not towards the end of the Triassic or at the beginning of the Jurassic...!

 

1419939013_Penarthteleosauridtooth04.thumb.jpg.4965030ee400c8000c3e3f799bbfb7da.jpg1021008147_Penarthteleosauridtooth03.thumb.jpg.3172a5c16d388e4bc0a830f8e69d565f.jpg97396617_Penarthteleosauridtooth02.thumb.jpg.20d5dc3cd0fe162cc8a131a36e644bfa.jpg1370001026_Penarthteleosauridtooth01.thumb.jpg.ce38f6fe85017b6b5fdfa7954bc3f91a.jpg

 

 

So bar the fact that I may have misidentified the tooth - which I don't belief I have - could it be that, much as was the case with this metriorhynchid tooth, the locality information I received with it is wrong? At the same time, preservation seems quite different from what I'm used to seeing from Peterborough (although, to be fair, there is some similarity in colour patterning with my metriorhynchid tooth), as well as Stonesfield, where I've got the below tooth from:

 

264129636_Marinecrocodilecf.Steneosaurussp.toothStonesfieldSlate02.jpg.6ee2f21848a85146f48947c30a87d355.jpg1328853079_Marinecrocodilecf.Steneosaurussp.toothStonesfieldSlate01.jpg.e6fc347d802ea16d129b430240665a25.jpg1388385372_Marinecrocodilecf.Steneosaurussp.toothStonesfieldSlate03.jpg.84e4742b3e1b463d6212d94567037af4.jpg

 

 

Rather, the root seems more hardened (unfortunately, I don't, however, have the specimen with me right now), much more reminiscent of the beach finds made in the French Boulonnais, as in the machimosaurid tooth in this post.

 

Any ideas, @paulgdls @DE&i @Welsh Wizard @fossils-uk?

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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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  • 8 months later...
37 minutes ago, Alston Gee said:

@pachy-pleuro-whatnot-odon Hi Pachy, would you label the tooth below as Peloneustes philarchus or a marine crocodile? This tooth indeed shares some similarities with the first tooth you posted.

IMG_3545.jpeg

IMG_3546.jpeg

May I recommend a new topic under fossil ID vs adding onto these older, longer threads?  A lot of ID's lose visibility when added to these longer, more aged topics.

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*Frank*

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3 hours ago, FB003 said:

May I recommend a new topic under fossil ID vs adding onto these older, longer threads?  A lot of ID's lose visibility when added to these longer, more aged topics.

 

3 hours ago, Alston Gee said:

@pachy-pleuro-whatnot-odon Hi Pachy, would you label the tooth below as Peloneustes philarchus or a marine crocodile? This tooth indeed shares some similarities with the first tooth you posted.

IMG_3545.jpegIMG_3546.jpeg

 

While I agree with Frank in that this should've become it's own ID topic, which either of us could've then linked to this thread to increase visibility of both through cross-linking, I'll just go ahead and answer your question here. Basically, as I haven't seen any photographs of this specimen exhibiting clear carinae, I'd say this is indeed the lower third of a pliosaur tooth. And while there isn't overly much to go on in terms of identification (which mostly proceeds based on the pattern of striations in pliosaurs), I'd say that the similarities with my tooth above as well as certain striae being restricted to the base of the tooth makes me think Peloneustes philarchus is more likely than marine crocodile, which generally have striae that do run the full apicobasal height of the tooth (though there are exceptions, yet none remaining as low as in these two specimens).

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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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