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Showing results for tags 'crocodilians'.
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One for the (marine) crocodile specialist...
pachy-pleuro-whatnot-odon posted a topic in Questions & Answers
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. 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... 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!- 14 replies
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Hello Everyone! Seems to be a good bit of interest in this topic, so I thought I’d make a little summary on what types of crocodilians you may find along the Calvert cliffs. Most of this information is gleaned from Dr. Robert Weems’ “Crocodilians of the Calvert Cliffs” in Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA, available freely by clicking the underlined portion. I encourage you to read that for more detail. If you have anything to add or you notice any mistakes, please let me know! Thecachampsa This genus is the only described genus along the cliffs, of which two species are described in this area. Among extant (living) creatures, it is most closely related to the false gharial. All large non-shark coprolites along the cliffs are assumed to be produced by Thecachampsa. Their vertebrae, like all reptile vertebrae, have a convex side and a concave side, making their vertebrae look like they have a ball and a socket. Their osteoderms are distinctive, with thick, blunt sections between the pits. Osteoderm associated with T. sericodon, from “Geology and Vertebrate Paleontology of Calvert Cliffs, Maryland, USA”
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Is it generally impossible to distinguish different croc species, even from just half a dozen from a certain location, by most individual bones, like humerus’/arm/leg bones, and individual verts? I know experts can definitely do so if they have the bone in-hand, and proper tools, but in THIS situation, through just pics, there’s not much that can be done unless there’s something that stands out, like unusually large size or something, is there?
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