A revision of Nearctic species of the genus Geostiba Thomson, 1858 (Coleoptera: Staphylinidae: Aleocharinae)

Nearctic species of the genus Geostiba Thomson, 1858 are revised. Redescription and illustrations are provided for distinguishing the genus Geostiba from other aleocharine genera. Six new species of Geostiba are described (G. (Sibiota) crepusculigena Gusarov, sp. n. from Tennessee, G. (S.) pluvigena Gusarov, sp. n. from North Carolina, G. (S.) coeligena Gusarov, sp. n. and G. (S.) nebuligena Gusarov, sp. n. from Tennessee and North Carolina, G. (S.) appalachigena Gusarov, sp. n. from West Virginia, Virginia, Maryland, Pennsylvania, New Jersey, New York, Massachusetts, Rhode Island, New Hampshire, Maine, Wisconsin and Quebec; G. (S.) silvigena Gusarov, sp. n. from California). Nine species are redescribed (G. (S.) alticola Lohse & Smetana, 1988, G. (S.) balsamensis Pace, 1997, G. (S.) bicarinata Lohse & Smetana, 1988, G. (S.) graveyardensis Pace, 1997 and G. (S.) nubigena Lohse & Smetana, 1988 known from North Carolina, G. (S.) carteriensis Pace, 1997 and G. (S.) nimbicola Lohse & Smetana, 1988 known from Tennessee and North Carolina, G. (S.) impressula (Casey, 1906) known from Oregon, and G. (s. str.) circellaris (Gravenhorst, 1806) introduced from Europe to Newfoundland). A key for identification of Nearctic species of Geostiba is provided. Geostiba impressula (Casey, 1906) is removed from synonymy with G. circellaris. Ditroposipalia Scheerpeltz, 1951 is placed in synonymy with Sibiota Casey, 1906 (a valid subgenus of Geostiba), Geostiba fossata (Casey, 1910) with G. impressula (Casey, 1906), Sipaliella Casey, 1911 with Meotica Mulsant & Rey, 1873 (a valid genus in tribe Oxypodini) and Sipalia (Sipaliella) filaria Casey, 1911 with Meotica pallens (Redtenbacher, 1849). Tylosipalia Scheerpeltz, 1951 is confirmed to be a synonym of Typhlusida Casey, 1906 (a valid subgenus of Geostiba). The lectotype of Sipalia fossata Casey, 1906 is designated. The geographical distribution of Geostiba in the Southern Appalachians is discussed.