Loc: Virginia, USA
I heard this just the other day on BBC Radio 3's "Private Passions" show ... it's just wonderful. The subtitle is "A Mexican Serenade." I'm not completely sold on that because it sounds 100% Joplin but, yes, a wonderful piece.
I wouldn't claim to know much about Mexican music of the time, but tango and habanera rhythms in new world music first showed up in Cuba and Argentina, not Mexico. Cursory googling reveals that Mexican tango dates from around 1917, which is around the end of the ragtime era.