pachy-pleuro-whatnot-odon Posted October 1, 2021 Share Posted October 1, 2021 Hi all, I bought this Kimmeridgian plesiosaur tooth from the Faringdon sponge gravels a while back. It came identified as Colymbosaurus sp.. At that point, I simply accepted this identification, seeing as the teeth of Colymbosaurus (or, at least, what's suspected of being Colymbosaurus) were already known from the Etches Collection and I didn't really have the means to verify the ascription from online sources. Today, however, The Etches Collection posted a video on Kimmeridgian plesiosaurs on their YouTube-channel, which make it abundantly clear that my specimen doesn't correspond to Colymbosaurus (video referenced below, as is a photographic excerpt of the teeth). The teeth of Colymbosaurus are not only subtrihedral but gracile in shape, they also have very strong striations - much stronger than in my specimen and almost pliosaur-like. The striations on my specimen, on the other hand, are way more similar to those of the Oxford Clay Tricleidus seeleyi, with very fine striations all along the tooth, a round cross-sections and (obviously) without carinae (just to rule out marine crocodile). My question now is: can my tooth be identified as to species or even genus? Could it be that the temporal range of Tricleidus extended into the Kimmeridgian? Might this tooth belong to Kimmerosaurus? Steve mentions in his video that there are more plesiosaurs that remain to be described from the Kimmeridge Clay, so, with that in mind, should I just classify mine as "cf. Crypticlididae indet."? Any ideas and suggestions welcome, but will just also tag @paulgdls and @DE&i. '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 Link to comment Share on other sites More sharing options...
Coco Posted October 1, 2021 Share Posted October 1, 2021 Maybe the size might help ! Coco 1 ---------------------- OUTIL POUR MESURER VOS FOSSILES : ici Ma bibliothèque PDF 1 (Poissons et sélaciens récents & fossiles) : ici Ma bibliothèque PDF 2 (Animaux vivants - sans poissons ni sélaciens) : ici Mâchoires sélaciennes récentes : ici Hétérodontiques et sélaciens : ici Oeufs sélaciens récents : ici Otolithes de poissons récents ! ici Un Greg... Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted October 1, 2021 Author Share Posted October 1, 2021 (edited) 14 minutes ago, Coco said: Maybe the size might help ! Valid point, though most plesiosaur teeth from either Oxford of Kimmeridge Clay fall within the same overall size range. Anyway, this one's 15.9mm tall, with a diameter of 6.1mm. I'm also going to take this opportunity to come back on my observation of fine striations, as this was an observation made with the naked eye. However, on inspection with a lens, it turns out that what look like striations are actually the remnants of the tooth's enamel, with the striae suggested by regular and straight apicobasal crazing/cracking of the enamel in between... As such, it's very well possible that the tooth originally didn't bear any ornamentation. Edited October 1, 2021 by pachy-pleuro-whatnot-odon '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 Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted March 21, 2022 Author Share Posted March 21, 2022 Any ideas on this one, @PointyKnight? '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 Link to comment Share on other sites More sharing options...
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