Thursday, 18 March 2010


This year in Tucson I bought a few Ptychodus teeth, the first time I've had them in years. Ptychodus was a shark around in the Cretaceous and for a little while after, and there are a few species. It doesn't fit most people's idea of a shark, as it lived on a diet of giant clams and has been described as a 'sluggish bottom-dweller' - not something you'd really want on your gravestone. The teeth I have are rounded, stumpy pegs, used for crushing heavy-duty shells rather than ripping fish into fleshy shreds. Ptychodus had big tooth-plates, like some vegetarian dinosaurs, and while interesting, they don't quite capture the imagination in the way a huge megalodon tooth does.

Anyway - I noticed a new discovery of Ptychodus mortoni had been made in Kansas, dating to about 88-89 million years ago, when that area was covered by a vast shallow sea. This one was a lot bigger than previously known, clocking in at over 30 feet long. Would take a lot of clams to keep it happy. It doesn't come as too much of a surprise that a clam-eater could get to be monstrously big. Walrus also eat mostly clams, and they seem to do alright by it. Wouldn't want to sit next to a walrus on the bus.

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