Ancient fossils reveal how the mollusc got its teeth
The radula sounds like something from a horror movie -- a conveyor belt lined with hundreds of rows of interlocking teeth. In fact, radulas are found in the mouths of most molluscs, from the giant squid to the garden snail. Now, a "prototype" radula found in 500-million-year-old fossils studied by University of Toronto graduate student Martin Smith, shows that the earliest radula was not a flesh-rasping terror, but a tool for humbly scooping food from the muddy sea floor.
FOSSIL SOFT-SHELL TURTLE Trionyx sp. Eocene, Green River Formation Kemmerer, Wyoming, USA In this case, the top shell - known as the carapace - has been fossilized, along with a complete set of impressive ribs that seem to come right out of the shell