Resumen: Here we describe the new fossil site of El Horcajo in the vicinity of Trevijano (La Rioja, Spain). It is located in the palustrine facies of the Enciso Group (Cameros Basin). This new locality has provided dozens of eggshell fragments, together with other vertebrate remains and charophyte fructifications, which allow dating of the locality as Valanginian-Hauterivian. Five ootaxa have being recognized: 1) the Spheroolithidae Guegoolithus turolensis; 2) a surprisingly thick Prismatoolithidae indet., with certain affinities to the oogenus Sankofa, that may represent a new oogenus and oospecies for this oofamily; 3) the Krokolithidae Idioma: Inglés DOI: 10.7203/sjp.31.2.17158 Año: 2016 Publicado en: Spanish Journal of Palaeontology 31, 2 (2016), 305-320 ISSN: 2255-0550 Originalmente disponible en: Texto completo de la revista