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  • Dr. Ronny Maik Leder posted an update 5 years, 5 months ago

    5 years, 5 months ago
    5 years, 5 months ago

    Hey Teddy @teddy-badaut,

    yes you are right Gottfried et al. simply scaled C. megalodon using isolated anterior teeth and estimated TBL based on the proportions of C. carcharias. I agree with you that using the dentition size might result in much better estimates than using just single teeth (just think about what Victor mentioned about his estimates using the Shimada method (just like Catalina Pimiento in her paper) at an associated Meg set from Gordon Hubbell – very big differences in BL from the symphysis to the commissure). I think your idea is great and we should continue with it but still there will be the uncertainty that we don’t know the jaw-body proportions unless we find a complete specimen. All we know is that this shark was very big – something between 12 and 20 meters and until we find a complete articulated specimen we cannot say more than that. BUT, and that is what this forum is for, we can get as close as possible for example with ideas like yours. BTW: I can not find your attachments but I am really interested in it since my specialty is in fossil sharks, although more with Carcharhinidae (morphometric teeth analysis) than with Lamniformae.

    regards

    Ronny

    • Hey Ronny @rleder ,

      Thank you for the kind words. I think that using dentition size for fossil macropredatory lamniforms has been already proposed a few times but I’ve always found strange that no one already had the idea to perform TL extrapolations from the available sets, though thinking about it I guess one of the reason was that they are in privates collections. I am glad that Victor had finally the opportunity to work on them (and he informed me about an even larger Chilean set).

      I have to say I had already remarked the vast discrepancies while using Shimada’s method on all teeth positions of the sets. I thought that Catalina Pimiento had already tested this since she reported measurements of the associated sets in her thesis and her 2010 paper.

      I think Catalina is gonna study the Belgian partial backbone, I had contacted the Museum about it and they told me it was stored since a long time but that Catalina planned to go there to study it.

      Certainly we don’t know how proportionned were the jaws of Meg but in absence of contradictory data, I doubt it should be reconstructed with an absurdly large dentition for its body length, especially with the estimated 200+vertebra count suggested by Gottfried et al.
      I think that Ward, in Renz 2002, said that dentition size is pretty stable in relation to the body in large predatory sharks…

      I have to precise I’m absolutely not scientist, merely a shark paleo-enthusiast, I merely want to contribute and suggest to search in that direction but at my own level I certainly have less ability to establish a definitive data. But yes ! I strongly think that dentition size is the best proxy to use, and if confirmed, using larger isolated teeth known from private collections could be used to estimate potential max size in the species.

      Strange that my attachement is not available on the forum…

      I’ve found your email on the FLMNH site, I send you my Word paper attached.

      I certainly guess that the potential data gathered from these sets to estimate body size could be used with some Carcharhinidae (thinking about H. serra…).