Arhuaco Adams & Bernard (1977) is one of the least known genera of Neotropical Satyrinae. It comprises two species and presents an unusual disjunct distribution, with A. ica Adams & Bernard (1977), endemic to the isolated Colombian Sierra Nevada de Santa Marta, and A. dryadina (Schaus 1913) found in the mountains of Costa Rica and Panama. Here, the female of A. dryadina is described, and a new generic diagnosis is presented. Affinities with other genera of the subtribe Pronophilina, in particular the potential closest relatives, such as Pronophila Doubleday (1849), are investigated based on morphological, molecular, ecological, and behavioral data. Results from molecular and morphological sources are incongruent. Molecular data indicate that Arhuaco is paraphyletic, with A. dryadina segregating within the Pronophila clade. Morphological data, by contrast, indicate a closer affinity between the two species currently placed in Arhuaco, favoring the monophyly of the genus, and show no consistent synapomorphies for Arhuaco + Pronophila. A vicariance biogeographical scenario is evaluated.
Keywords: Arhuaco; COI; Costa Rica; Pronophila; Pronophilina; RpS5; Sierra Nevada de Santa Marta; cloud forests.