Previously only recorded as a single species, at least five additional new species are hiding under the name Chilomys instans. After eleven years of field work in different regions of the Ecuadorian Andes, an international group of researchers with the participation of the LIB was able to describe five new species of the mouse genus Chilomys. The species, which were so far completely unknown to science, live at altitudes between 1,200 and 4,050 metres. The genus Chilomys turns out to be a group of morphologically distinctive Andean rodents with unique specialisations. The names of the new mice species honour important personalities.