ABSTRACT Wandesia (Partnuniella) lehmanni n. sp. is described from a high-altitude lake in the Colombian Andes. It can be easily distinguished from all known members of the subgenus Partnuniella K. Viets by the increased number of acetabula. A key to South American species of the subgenus Partnuniella K. Viets is provided. Key words: Acariwater mitesnew specieshigh-altitude lakeAndesColombia ACKNOWLEDGEMENTS The project was sponsored by the British Ecological Society (Small Ecological Project Grant 1159/1438), the Universidad Pedagógica y Tecnológica de Colombia, and the Corporación Autónoma Regional de Medioambiente de Boyacá (Corpoboyacá, Colombia), with additional support by the Onda Town Council (Spain) to Bioestudios Saganta (SHP). We specially thank Bioservice Ltd. (Colombia) and Zully Ojeda for logistic support.