Aguilar/Escobedo and Barrios/Salazar

I'm trying to put together a Ethnic Ancestral Lineage about my Great Grandfather Celso Barrios Aguilar (B.April 27, 1908) In Jerez, Zacatecas, Mexico. His Parents Were Pedro Aguilar (B. April 26, 1870) In Tepetango, Zacatecas and Mariana Barrios (B. April 17, 1875) In Monte Escobedo, Zacatecas. Pedro's Parents Were Juan Aguilar (1837) and Maria Guadalupe Escobedo (1836) both born In Tepetango, Zacatecas, Mexico. Mariana's parents were Jose Perfecto Barrios (1835) and Maria Valenta Salazar (1856) Both also from Tepetango, Zacatecas, Mexico. Celso appears to be of African and European Descent, I'm interested in learning more about the African bloodline and which of my ancestors carried it. I searched records upon records and came up empty, I went back as far as the late 1700's on Pedro's and Mariana's family and nothing.

If anybody has any Ethnic information of Celso or his Parents, I would much appreciate the help...

Muchos Gracias,
David Martinez