The enigmatic ailurid <i>Magerictis imperialensis</i> (Mammalia: Carnivora) unveiled: a systematic approach to the early Ailuridae

We present a detailed description of the craniodental and postcranial remains of the enigmatic <i>Magerictis imperialensis</i>, a basal Ailuridae previously known only from a single m2 from the Middle Miocene of the Madrid Basin (Spain). The discovery of new specimens from eight Middle Miocene (MN5–MN6) localities in Madrid has yielded comprehensive information on the dentition, mandibular morphology, and postcranial skeleton of this species. These new fossils provide an excellent opportunity to revise the phylogenetic relationships of <i>Magerictis</i> and related musteloids from the Oligocene and Miocene of Eurasia and North America. Our phylogenetic analysis indicates that <i>Magerictis</i> and <i>Rothictis</i> gen. nov. are the most basal members of the Aiuluridae. Both genera, together with <i>Alopecocyon</i>, <i>Actiocyon</i>, and <i>Protursus</i>, underwent a limited adaptive radiation during the Middle and Late Miocene in Eurasia and North America. This radiation potentially includes the ancestors of the most specialized ailurids (<i>Simocyon</i>, and the ailurines <i>Parailurus</i>, <i>Pristinailurus</i> and <i>Ailurus</i>). The postcranial elements attributed to <i>Magerictis</i>, particularly the astragalus and calcaneus, exhibit a morphological pattern comparable to that of <i>Ailurus</i>, thereby distinguishing it from other Musteloidea. A systematic rearrangement of the primitive Holartic musteloids from the Oligocene and Miocene is proposed. The Ailuridae are divided into three subfamilies: (i) Ailurinae for <i>Ailurus</i>, <i>Parailurus</i> and <i>Pristinailurus</i>; (ii) Simocyoninae, which includes <i>Simocyon</i>, <i>Protursus</i>, <i>Alopecocyon</i> and <i>Actiocyon</i>; and (iii) Magerictinae nov. rank for <i>Magerictis</i> and <i>Rothictis</i> gen. nov. (type species <i>Rothictis wintershofensis</i> comb. nov.). The family Amphictidae Winge, 1895 is revalidated for <i>Amphictis</i> and <i>Bonisictis</i> gen. nov. (type species <i>Bonisictis ambiguus</i> comb. nov.). https://zoobank.org/urn:lsid:zoobank.org:pub:15D893D5-0C61-4652-8919-DAEF998F3953