New on AAAS: The World's Rarest Whale

For 150 years, all that was known of the spade-toothed beaked whale (Mesoplodon traversii) was gleaned from two skull fragments and a jaw bone. Then in December 2010, two individuals - a mother and her male calf - washed up on a New Zealand beach.Read more about this enigmatic marine mammal and how scientists were able to positively identify it (pdf or link).