Abstract
BACKGROUND: Mexican terrestrial malacofauna is highly diverse, but poorly studied. The genus Humboldtiana includes near to 60 species, most with insular distributions on single mountains from South Texas (USA) to entral Mexico. NEW INFORMATION: Humboldtianadugesi sp. nov. is described from the state of Guanajuato, Mexico. This new species represents the first one described for the state and is diagnosed by the following combination of characters that allow distinguishing for other species included in the genus, a protoconch with growth lines and granulated microsculpture, a globose penis that bears a stout verge that covers half of the penis cavity and a long flagellum that is four times longer than the combined length of the penis and epiphallus.