I do not see a father for Antonio mentioned. It looks like naturale di Maria, or natural child of Maria. Perhaps he was born out of wedlock. I would look for his birth record and see if there is a father mentioned. I believe there is a mention of a marriage (or maybe it is saying there was not one) about his mother in the handwritten section at the bottom listing the documents presented. My Italian is limited so maybe someone else can tell you what exactly it says.
The marriage was recorded on 29 October 1881 and Antonio was 21 years old and a shoemaker.