Systematics and biogeography of the subantarctic <i>Leptusa</i> (Coleoptera: Staphylinidae: Aleocharinae: Homalotini)

<i>Leptusa atriceps</i> and <i>L. antarctica</i>, flightess representatives of the nearly global genus <i>Leptusa</i> in the remote and widely distributed subantarctic islands, are taxonomically revised. Identity and the widely disjunct distribution of <i>L. atriceps</i> on Falkland, South Georgia, Marion, Crozet and Kerguelen Islands are confirmed. <i>Leptusa antarctica</i> is found to be a complex of five species restricted to the subantarctic islands of New Zealand. Two of these species, <i>L. sparsepunctata</i> and <i>L. nesiotes</i> are here reinstated from synonymy and two others, <i>Leptusa insulae</i> sp. nov. and <i>Leptusa steeli</i> sp. nov., are described as new to science. The monophyly of subantarctic <i>Leptusa</i> species united in the subgenus <i>Halmaeusa</i> was determined by a phylogenetic study of five exemplar homalotine genera and 17 representatives of <i>Leptusa</i> from South America and the Holarctic based on 76 adult morphological characters. Phylogenetic placement of <i>Halmaeusa</i> was not firmly established. <i>Nanoglossa</i>, a temperate South American subgenus of <i>Leptusa</i> was found as a possible sister group to <i>Halmaeusa.</i> The distribution of <i>Halmaeusa</i> species with two to four species that occur sympatrically on Campbell and Auckland Islands, and other species distributed across several remote islands, provides a framework for future biogeographic study of the subantarctic <i>Leptusa</i>. http://www.zoobank.org/urn:lsid:zoobank.org:act:82509B9D-4BF6-47E1-B6F7-396ED193A0FA; http://www.zoobank.org/urn:lsid:zoobank.org:act:40A3D6FC-27FF-4070-88CA-1B519ABE760A