was highly endemic. Deméré and Berta consider Aetiocetus to be a lineage endemic to the north Pacific Ocean basin. High endemism would be highly atypical of mysticetes. However, a more likely explanation is that the fossil record for Aetiocetus is poor, or that a sampling bias is present and not enough work has been done in late Oligocene deposits in the south Pacific Ocean. Perhaps there are more specimens of Aetiocetus that will be discovered as paleontologists continue searching. The other genera in the family Aetiocetidae are Ashorocetus, Chonecetus, Morawanocetus, and Willungacetus. All aetiocetids are known from the North Pacific except the Australian Willungacetus and its taxonomy is disputed. See also Evolution of cetaceans References Aetiocetidae Transitional fossils Prehistoric cetacean genera Oligocene cetaceans Rupelian life Oligocene mammals of Asia Oligocene mammals of North America Whitneyan Paleontology in Oregon Fossil taxa described in 1966