Hyla is a genus of tree frogs in the family Hylidae. Over the years, scientists have changed their minds about which frog species should be in "Hyla" and which should be in "Litoria", "Ranoidea" or other genera. At one time, "Hyla" had more than 300 species from Europe, Asia, Africa, and across the Americas. Now, "Hyla" has only 17 extant (living) species. They are from Europe, northern Africa and Asia. The earliest known fossil from a "Hyla" frog is †"Hyla swanstoni" from the Eocene. The fossil was found in Saskatchewan, Canada, but it is not clear whether we would consider "swanstoni" a "Hyla" frog today.