http://www.sciencemag.org/news/2020/05/saber-toothed-anchovies-roamed-oceans-45-million-years-ago

When dinosaurs and other large predators went extinct some 66 million years ago, lots of creatures evolved to take their place. But unlike the plankton-hunting anchovies we eat in Caesar salads today, some ancient anchovies evolved into fish-eating predators, according to a new study.

Researchers examined a 30-centimeter-long fossil embedded in a rock formation near Chièvres, Belgium, and another partial fossil from Pakistan’s Punjab province. They were between 41 million and 54 million years old, and both shared a peculiar feature: a single saber tooth on the upper jaw.