The name Martín Fierro is familiar, but I wish my memory were better. I took two Latin American literature courses in college in the late 60's (in Spanish), and I can't remember if we read or just discussed Martín Fierro. I think it was more likely the latter.

But I didn't know (or study) Omar Moreno Palacios. I listened to the Sencillito clip, and even with my poor Spanish skills, I could tell he was doing something special with the language and timing.

So your Obscure Obit has given me two important figures to study further (José Hernández and Omar Moreno Palacios).