News of the WeekEvolution

Tooth Theory Revises History of Mammals

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Science  05 Jan 2001:
Vol. 291, Issue 5501, pp. 26
DOI: 10.1126/science.10.1126/SCIENCE.291.5501.26

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The most important advance in mammalian dental evolution has long been regarded as the tribosphenic molar--a Cuisinart-like tooth that could both slice and grind. This was considered a key innovation, shared exclusively by placental mammals and marsupials, that helps explain their extraordinary success ever since the Cretaceous period. Now three paleontologists propose that the tribosphenic molar evolved not once, but twice--a highly provocative idea.