Date when external appearance was first known 

More than one editor has reverted the 2012 date to 2010 on good faith. As the two specimens were originally thought to be Gray's beaked whale, the 2010 date can not be used as they hadn't been identified as spade-toothed yet. As such, the 2012 date of the paper should be used to be safe. Please do not revert before explaining why it should be changed here. Thank you.