Interesting Baptism Name

This is a new one for me. Has anyone ever seen where a name that is traditionally a last name is actually made to be part of a 1st name? I found the baptism record for my 5th great grandfather. On most records he is listed as Juan Hernandez or Juan Antonio Hernandez. His parents were Cristobal Hernandez and Maria de la Encarnacion Vallin (or Ballin). On his baptism record his first name is listed as "Juan Jose Antonio Bautista". Bautista is not his last name. So his whle name at baptism would be Juan Jose Antonio Bautista Hernandez Vallin. 

 

Attached is the document. Just wondered if anyone had thoughts on this? Maybe his name was inspired by someone somewhat notible/of important historic reference at the time?