Thanks for the idea. Maybe I can find his death certificate in Argentina and that should say date of birth and more ... maybe.

Piantieri is right spelling.. a Piantieri italian family, but coming from Rio de Janeiro came in USA also, maybe related with your Domenico....

-Concetta Piantieri Rio de Janerio 1905 44
Concettina Piantieri Rio de Janerio 1905 10
Giovanni A. Piantieri Rio de Janerio 1905 48
Maria Piantieri Rio ...

Did he live and die in Argentina? I would try to get records in Argentina that might show where he was born before I attempt to get records from Italy. After all he was in Argentina much longer.

Or if he was in the USA for a long time, I would try to get his application for Social Security ...

I've been having a hard time locating my great grandfather's birthplace. I know he came from Napoli, Italy.
Name: Domenico Piantiere (it was spelled wrong it should have been Piantieri)
Nationality: Italian
Port: Napoles
Arrival: Argentina
Data: Oct 09 1883
Ship name: Vayndick Tenier
Age: 1

Some ...