Eucera (Cubitalia) breviceps (FRIESE, 1911), hitherto only known from Turkey and Syria, was discovered in the southern part of Massif Central (France), in the “Grands Causses” area, a few years ago. It has been found to be distributed throughout it, also present in the French Alps and Italy (Valle d’Aosta, Abruzzo) as well as in southwestern Bulgaria and northern Greece. Our article presents the corresponding data, originated from field work and examination of material in collections, and gives new data for Turkey from material in the collection of the Oberösterreichisches Landesmuseum, Linz (Austria). Several ecological traits of E. breviceps are discussed. We especially highlight the close association between E. breviceps and the plant genus Onosma L. (Boraginaceae), based on literature and our field observations. Both their ecological requirements and their interactions illustrate the complexity of such relationships and their potential vulnerability in the context of global change. Through this remarkable example of an oligolectic interaction, we aim to promote a better consideration of pollinators, notably bees, and pollinator networks in conservation biology.