First appeared?

Boom boom chakka chakka boom boom.

The dance associated with the rhythmic delights of a beat box pumping out it's mega bass tunes, in which a youthful gyrator would acrobatically spin round on their head or whatever other appendage was appropriate at the time, is one most people think of as being a modern phenomenon. Certainly, they would place break dancing as a thing of the 80's, or maybe 70's if pushed. 

Footage showing this exact same thing being done in the 1930's is catching many by surprise.

Dance innovation

Kids today - pah! They just don't get that all the oldies around them were exactly the same as they are at one point. And yes, that includes having the energy and fitness to dance around as much as they pleased, any way they wanted. There's a misconception amongst the young that the oldies, such as Fred Astaire, Gene Kelly etc - were somehow old and doddery even back in their day. The truth is they would outclass many top Olympic athletes of today before breakfast, and were doing so for much longer in their lives than today's "entertainers".

Black culture has always deliberately separated itself to forge its own identity, and has often been mimicked or just plain hijacked when it seemed opportune to do so. For example, not to take away any of his fantastic natural ability, but Elvis began and made his breakthrough singing in an African/American style back in 1953, and the rest is history.

Break dancing is associated with the beat heavy techo music which accompanies it, so in people's minds it is part and parcel of that. Since there were no beatboxes or ghetto blasters before the '80's, they are assuming the dancing style didn't exist before then too.

Mills Brothers

This isn't the original music from the video - that's not available - but just take a look at these moves: