Da Costa

The "da" or "de" that you sometimes see in front of portuguese surnames are never capitalized! It would be for example [Blank] da Costa, not Da Costa, Dacosta or DaCosta which are common ways non portuguese speaking people write the surname. The "da" and "de" are also very common yet optional suffixes in a lot of other Portuguese surnames (ex. [Blank] da Silva, [Blank] de Carvalho, etc.)