When I identify unknowns anywhere, I sometimes find an audio observation of Eleutherodactylus in Hawaii which was either unidentified or misidentified as a bird. It’s easy to tell that it’s a common coquí, because that’s the only species found there.
When I identify in the Antilles, though, there are several species in Puerto Rico, including the upland coquí, and many observations have photos but no sound. I’ve only heard only the common coquí, walking around in the evening, and not seen it or heard any other species. If I find one that’s already identified at least to genus, how can I tell by looking what species it is? How can I tell the common and upland species apart by sound? Or should I look at the elevation?