Thanks. I actually looked at that Wikipedia article but was not sure, since the frog I stumbled upon blended in with the scenery so amazingly well, that I didn't believe it could actually be just a colour variation. I mean even the lines on its skin and the eyes matched the limestone perfectly.
Another thing that I found weird is that the article describes them as being "strictly nocturnal" whereas this little fellow was moving around in the middle of the day. My guess is we might have startled him as he was resting, which would explain why he was out and about at noon.