I have searched my data base and I did not find Otilano or Ysidra
Yniguez. I have Herreras with the first name of Jose and Manuel but I could not make a connection to Otilano. I looked Tlaltenago de
Sanchez Roman and it is not near
Villa de Cos. Tlaltenago is at the southern tip of Zacatecas. I looked the town in the Family History Catalog and it is a municipal seat. The Family History Library has microfilm on Baptismals from 1630 through 1961, Church marriages from 1926 through 1961, Church burials from 1686 through 1956, Civil births from 1867 through 1950, Civil marriages from 1867 through 1914, Civil death records from 1867 through 1914 and census records. Visit you local Family History Library,
Mormon Church or visit their website. Lots of luck.