Peruvian scientists have found a fossilised skull of a giant river dolphin, belonging to the Platanistoidea family of dolphins commonly found in the ocean 24 to 16 million years ago. The animal would have measured up to 3.5 metres long, making it the largest river dolphin ever found. The fossil is remarkable because it has no links to the river dolphins that now swim in the waters it once inhabited. The Guardian has the full story.