Baker and colleagues found that the Laridae lineage diverged from a lineage that gave rise to both the skuas (Stercorariidae) and auks (Alcidae) before the end of the Cretaceous in the age of dinosaurs. They also found that the Laridae themselves began expanding in the early Paleocene, around 60 million years ago. The German palaeontologist Gerald Mayr has questioned the validity of these early dates and suggested that inappropriate fossils were used in calibrating the molecular data. The earliest charadriiform fossils date only from the late Eocene, around 35 million years ago.