jeudi 8 août 2013

Frilled Shark Teeth

With Shark Week going, I've been seeing a lot of shark pictures on the websites I frequent. Being in a hotel, my mind is wandering. In very odd directions, it turns out.



I saw a picture of a frilled shark. These are....weird. They're sea monsters. Think of the descriptions of sea serpants, and they're that, on a smaller scale. But that's not what struck me. No, what struck me is the teeth.



The teeth are aranged in a very peculiar manner. Shark teeth are always aranged in rows, so that any tooth breaking off is replaced with a new one. But these guys take it to an absurd degree. The teeth are in very descreat rows, and the front portion of the tooth row seems to have the teeth pointing outward. This looks remarkably like an ancient shark, Helicoprion--or, more specifically, the tooth whorls (yes, that's the technical name). I'm wondering how close. And if there's a reason for it--similar feeding behaviors, for example. Probably not; the current view of Helicoprion has them using the tooth whorls remarkably like radula in mollusks. Still, the diet for both is supposed to be similar--a lot of squid--and the structures look, superficially, similar enough that I'd like to see more of the frilled shark tooth structure. The taxonomy seems a bit confused, but it doesn't appear that the two organisms are closely related, so that doesn't explain it.



The infuriating thing is, I can't find a good enough picture of a frilled shark tooth row from the side to compare the two. I know they're different, but I want to see the differences myself. And being a crab and, more recently, mammal guy, I doubt I'm gonna get any offers to disect a rare shark species.





via JREF Forum http://forums.randi.org/showthread.php?t=263509&goto=newpost

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