[Dixielandjazz] another question

[Kimberly Shaffer]

Here's the thing I still can't seem to figure out:

How do I register an original arrangement of someone else's composition 
so as to get publishing rights?

Example:  John Q Songwriter writes a song.  He copyrights that song 
with the US Copyright office.  30 years later, Paul B Arranger writes 
and records a new rendition of the song.  The new arrangement 
completely reworks the style and instrumentation.  The melody is still 
recognizable but it is different enough to be considered a "derivative 
work" by the copyright office, and thus copyrightable in its own right. 
  When the song gets played on the radio, John Q Songwriter and his 
publishing company obviously get a share of the royalties -- but Paul B 
Arranger feels his contribution to the song was unique enough to 
warrant a share of the royalties as well.  How does this work?  How do 
the big studios do it?