Surviving a Dark Age: The Oldest Baleen-Bearing Whales (Cetacea: Chaeomysticeti) of Pacific South America (Lower Miocene, Peru)
Journal: Life
Year: 2025

The evolution of baleen whales (Mysticeti) comprises two main phases, namely, (i) a Paleogene phase, which saw the diversification of stem lineages, and (ii) a Neogene phase, dominated by modern-looking, toothless, baleen-bearing forms in the monophyletic group Chaeomysticeti. These two phases are separated by a global turnover event coinciding with a gap-or "dark age"-in the mysticete fossil record. This dark age occurred between 23 and ~18 Ma and is apparently detected worldwide, except in Zea