Maggie,

AACR2R 21.3B1b states "make a new entry for a serial when...the main entry
for a serial is under a personal or corporate heading and the person or body
named in that heading is no longer responsible for the serial."

I would maintain that the reverse of this is true also.  If a serial, once
entered as a title main entry, is now under corporate authorship, it
warrants its own record.  I think this is a reasonable interpretation
considering the scope of _Oceanus_ has changed so drastically.

Hope this helps!

Norm Medeiros
Serials Assistant
UMASS Dartmouth
nmedeiros@umassd.edu