A greater understanding of mite biodiversity and ecology can explain their preference for microhabitats within host bodies, i.e., as ecto-, meso-, and endoparasites. Similarly, learning about the patterns formed by mite communities in wild animals can shed light on the mechanisms of parasitosis development in their domesticated counterparts. Hence, the present study examined the acarofauna of the mouflon, introduced to Poland in the early 20th century from a region of endemic occurrence. Forty-one individuals were examined for the presence of ectoparasites between 2010 and 2013; later, skin fragments were analysed for the presence of skin mites. A new species of Demodecidae, Demodex musimonis sp. nov., was discovered in the skin of the pasterns of 14.6% mouflons, as well as the ectoparasitic tick Ixodes ricinus (prevalence 29.3%) and ungulate-typical fly Lipoptena cervi (34.1%). However, no mites typical for ovine Ovis (Psorergatidae, Psoroptidae) were noted, nor any colonisation of microhabitats by species from local ungulates, resulting from the loss of original parasites during the introduction. A comparison of the acarofauna of the mouflon and domestic sheep Ovis aries aries suggests that a mite community with a complex structure and the co-occurrence of different families may be formed. However, it is not known whether the acarofauna of domestic sheep is derived from wild ancestors or the process of domestication. Even so, the peculiar Demodecidae must have been part of the natural parasitofauna of wild sheep, of which only D. musimonis sp. nov. has been recognised so far.