Phylogenetic relationships among cetartiodactyls based on insertions of short and long interspersed elements: Hippopotamuses are the closest extant relatives of whales

Retroposon presence-and-absence data from sampled living cetartiodactyls support Hippopotamidae as the extant sister group of Cetacea; this topology is not a fossil age, a direct ancestor or a nomenclatural catalogue decision.

The 55–0 Ma Whippomorpha route uses a rounded early Eocene navigation ceiling and combines the approximately 48.6 Ma Indohyus raoellid sample with living whale–hippo retroposon topology; neither source dates the Whippomorpha crown, and the span is not a direct lineage duration.