Llanocetidae
Llanocetidae is an extinct family of ancient toothed baleen whales from the Eocene. It was named by American paleontologist Edward Mitchell in 1989 after describing the Antarctic Llanocetus, but a 2018 study by paleontologists Ewan Fordyce and Felix Marx included the Peruvian Mystacodon and an undescribed New Zealand specimen OU GS10897.
