Pacific Tree Frog - Evolutionary History

Evolutionary History

The evolutionary history of these frogs is a very interesting one that is still being debated. Amphibians themselves are thought to have descended from the lobe-finned bony fishes. These fish had an ossified skeleton and emerged from the water as they developed limbs, girdles, and terrestrial characteristics such as lungs and a neck.

It is hard to figure out an exact frog lineage because of the lack of fossil record. The habitat in which these animals lived was moist and decay was quick. This was not helpful in preserving biological clues. The family of Hylidae is somewhat recent, appearing around 50 million years ago. The genus Hyla then appeared just after the dinosaurs went extinct. This genus originated in South America and expanded to the north into Mexico and eventually into North America. There was then a rise in sea level and the connection between the northern and southern populations was gone. They have been separate ever since, and have become genetically distinct from one another.

For this reason, the genus Hyla has been split into three separate genera: Aris, Limnaoedus, and Pseudacris. This is where the current confusion has taken place. Although the Pacific Tree Frog has carried the scientific name of Hyla regilla for many years, the most current consensus among scientists is that they should actually be Pseudacris regilla. This is still not agreed upon completely, and in the future we will see what becomes of these names.