The guidance notes for NBN's darwin core imports state that recordedBy is a required field.  Is there a convention for how this field should be filled in if the recorder is unknown.

I'm currently planning to set this as 'unknown' but would prefer to leave it blank if that would be acceptable (as 'unknown' is generally a nuisance for data users).

I have quite a large number of records where the recorder is unknown but there is a known compiler, so the record is not completely without provenance.  I don't want to shoe-horn the compiler's name into the 'recordedBy' field (in several cases the records are historic, created before the compiler was alive, so this would look like an error). Even where the recorder is known, 'compiler' is still useful information as it can help indicate the veracity of the record. I can't find an appropriate Darwin Core term to use for 'compiledBy'.  Do you know of anything usable that I've overlooked?