It might seem odd to group Cetaceans (whales) with Artiodactyls (hooved animals such as pigs, deer, camels, llamas, and hippos). But that is exactly what the combination of their scientific names into Cetartiodactyla is about. For some time, scientists had proposed that whales descended from land mammals, with the focus on the hooved fossil Mesonychia. In the 1990s, DNA sequences from many different genes revealed a closer relationship between whales and hippos than between hippos and any other hooved mammals. While it is not yet known what common ancestor whales and hippos share, the newly discovered relationship is getting attention. It appears that whales and hippos may have branched off from Artiodactyls as long as 60 million years ago. Scientists have proposed a new group called Whippomorpha (wh[ale] + hippo[potamus]; morphe = form) to include whales and hippopotamus and exclude other hooved animals.