The surname was her husband's surname (she was named
Ana Justina Ferreira). I didn't find the genealogy of Néri family at Brazil, but it seems a no-unusual surname; since there was a big migration of Italians in South
America (specially Arentina and Uruguay) it is not odd at all that
Isidoro Antônio Néri (her husband) was of Italian ancestry. But I really can't assure that.
Lumia
http://onomastica.mailcatala.com