Small to medium-sized mustelids from the last 18 million years represent a heterogeneous group of carnivorans with a wide-ranging record in the northern hemisphere. They were first referred to the genera Mustela and Martes, but lately ascribed to the latter, and hence considered as the longest-lived genus within Mustelidae. However, a great many of these forms have been based upon fragmentary material and Martes has conformed progressively to a wastebasket nomen for species of uncertain relationships. Here, we describe dentognathic material of a small-sized mustelid from three middle Miocene (MN7 + 8, latest Aragonian) localities of the Iberian Peninsula that constitutes a new genus and species. Aragonictis araid, gen. et sp. nov. represents a distinct taxon if compared with early/middle Miocene forms ascribed to "Martes" spp., especially the similar-sized early Miocene Circamustela? laevidens and the middle Miocene "Martes" caedoti and "Martes" delphinensis. The finding of particular features in A. araid (low p2-3, loss or reduction of the p4 accessory cuspid with its main cuspid centrally located, presence of a sharp, beveled and lingually open m1 talonid, and reduction of M1 lingual platform) indicates affinities with the late Miocene Circamustela in the range of hypercarnivory. Our reassessment of "Martes" indicates possible evidence of cladogenesis for Miocene mustelidae with, at least, two different events being recognized in Europe-the latter during MN7 + 8 to MN9 with presence of Aragonictis and Circamustela. The finding of A. araid further confirms the presence of more densely forested environments than expected in inner Iberia during the latest middle Miocene.