EDIT - I am now officially even more confused about these two species. I think this one maybe E. coqui and my photos of "E. coqui" in that species blog post may be E. portoricensis. Looks like I need to make another trip to Puerto Rico!
I believe this frog is the Upland Coqui (Eleutherodactylus portoricensis) It is very similar to the Coqui (Eleutherodactylus coqui). Both species occur in the area I photographed and recorded this frog. Their calls are also rather similar. The two species are similar enough that for many years they were both regarded as the same species of frog. The Upland Coqui has a higher pitched call which is most easily heard in the "qui" note of the call.
This is from the lowlands between the El Yunque Rainforest and the town of Naguabo. It had rained very heavily that afternoon and thousands of frogs were calling along the Rio Blanco river floodplain and forest edge. Although this frog was not recorded in the highlands, I still believe it to be Eleutherodactylus portoricensis. (If anyone knows any different, please leave a comment!)
This is the recording from the frog picture above calling near El Yunque.
© Chris Harrison 2013