REVISION OF NORTH AMERICANAGABUSLEACH (COLEOPTERA: DYTISCIDAE):ELONGATUS-,ZETTERSTEDTI-, ANDCONFINIS-GROUPS

Abstract

AbstractNorth American species ofAgabusLeach of theelongatus-,zetterstedti-, andconfinis-groups, as defined by Larson (1989), are revised. Study of character state distribution indicates that theelongatus- andzetterstedti-groups are clades within theconfinis-group but the names are retained in this paper to maintain consistency. Twenty species belonging to this complex occur in North America, namely:elongatus-group withA.elongatusGyllenhal andA.inexspectatusNilsson;zetterstedti-group withA.zetterstedtiThomson; and theconfinis-group withA.thomsoni(J. Sahlberg),A.moestus(Curtis),A.clypealis(Thomson),A.phaeopterus(Kirby),A.immaturussp.nov. (Great Lakes and Maritime Provinces regions),A.canadensisFall,A.audeniWallis,A.mackenziensissp.nov. (northwestern Canada),A.bicolor(Kirby),A.subfuscatusSharp,A.discolor(Harris),A.approximateFall,A.kootenaisp.nov. (southwestern Canada and northwestern United States),A.inscriptus(Crotch),A.smithiBrown,A.sasquatchsp.nov. (alpine areas of California and Nevada), andA.confinis(Gyllenhal). For each species the following information is provided: synonymy; description and illustration of taxonomically useful characters; notes on relationships, variation, distribution, and ecology; and a map of North American collection localities. A key to the North American species of theconfinis-group is presented. Lectotypes are designated forA.subfuscatusSharp,Gaurodytes inscriptusCrotch,G.ovoideusCrotch, andG.longulusLeConte.