Help please on my Lomelin ancestor?

Im pretty much stuck on this the Lomelin individual his name is Sebastian Lomelin he married Josefa Hurtado but i do not have their marriage record i descend from the offspring Maria Margarita Lomelin who married Rafael Yanez in 1762 in Nochistlan and i do have the record.Can someone please help me find Sebastian Lomelin parents?

Maria Margarita Lomelin And Rafael Yanez Marriage record

https://familysearch.org/pal:/MM9.3.1/TH-1-15184-37453-25?cc=1410092&wc=6835674