Archaeoceti ( `` ancient whales '' ) , or Zeuglodontes in older literature , is a paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene ( ) .
The Archaeoceti ( ` ancient whales ' ) , or Zeuglodontes in older literature , is a group of primitive cetaceans . They lived from the early Eocene to the late Oligocene , 55 -- 23 million years ago ( mya ) .