Solving the Giordano vs Giordani puzzle:
Nicola Rossi Giordano, tenor, replacing someone at Chicago Lyric, he is a Verdi and Puccini specialist.
Marcello Giordani, tenor, has just bowed out at the met because of severe laryngitis. This probably means vocal problems. He has been known to sing Arnold, the role with all the high C's in Rossini's William Tell.
Maybe one of them should change his name.