Caloplaca cancarixiticola Nav. -Ros., Egea & Llimona (Teloschistales, Lichenes) is described as new. It is characterized by a lobate thallus weakly attached to the substratum, and narrowly ellipsoid or ellipsoid-fusiform ascospores, (14.5–) 16–22(–25) × (4–)4–5–6um3 with a narrow equatorial wall-thickening, only (1–) 2.5–3.5(–4) um wide. This new species, related to the Caloplaca aurea-group of the subgenus Gasparrinia, was found on cancarixite, an ultrapotassic rock, in a volcanic region of Albacete (SE Spain).