Palposcydmus gen. n. from India, with a preliminary key to world genera of Stenichnini (Coleoptera, Staphylinidae, Scydmaeninae)

Palposcydmus yelamalai, gen. et spec. n. is described, based on specimens collected in Kerala, India. The new species is one of the smallest known scydmaenines, with the body length reaching merely 0.53–0.59 mm. Although in dorsal aspect resembling Microscydmus Saulcy & Croissandeau, Palposcydmus clearly differs in the presence of hypostomal sutures demarcating a subrectangular submental region, and enormously enlarged maxillary palpomeres 3. The new genus shows also a unique antennal structure not known in any other Stenichnini: the antennomere 3 is inserted deeply into the apex of pedicel, so that there is no constriction between them. Keys to extant genera of Stenichnini are given, in order to facilitate identifications separately to Indian, Eurasian & New Guinean, and to world genera.