In Latin, certain nouns that ended in -us in nominative singular had the same form in nominative plural (so-called "4th declension" nouns). The term "zero plural" refers to the lack of change in the English word, or lack of an overt plural morpheme, going from singular status to plural status.
"Anglicized plural" refers to borrowing the word into the English language, and treating it as an English word, where the regular plural is formed by the morpheme -s/-es. According to this view, the singular status will change into statuses when pluralised.
Some other words that end in -us were "2nd declension" in Latin, and form plurals by replacing the singular -us with -i (like alumnus becoming alumni in plural). These would be neither "zero plurals" (as there is an observable change in form), nor would they be "Anglicized plurals" (as an Anglicized plural would have been alumnuses).