Revision and phylogenetic analysis of the new world genus Neoclypeodytes Young (Coleoptera: Dytiscidae: Hydroporinae: Bidessini)

Abstract

The western North American and northern Central American genus Neoclypeodytes Young is revised. Twenty-five valid species are recognized in the genus. One additional name, N. luctuosus (Guignot) is treated as species of uncertain status. Eleven new species are described: N. amybethae, N. anasinus, N. astrapus, N. challeti, N. edithae, N. haroldi, N. megalus, N. nanus, N. roughleyi, N. similis and N. tumulus. Six new synonymies are established: N. centralis (Sharp)=N. cinctellus (LeConte): N. substriatus (Sharp)=N. discedens (Sharp); N. americanus Guignot), N. decoratus (Fall) and N. quadrisignatus (Sharp)=N. fryii (Clark); and N. rugulosus (Guignot)=N. obesus (Sharp). Lectotypes are designated for N. curtulus (Sharp), N. discedens, N. discretus (Sharp), N. lynceus (Sharp), N. obesus, N. ornatellus (Fall), N. pictodes (Sharp), N. plicipennis (Crotch), N. quadrinotatus (Sharp), N. quadripustulatus, N. quadrisignatus and N. substriatus. A key is provided for the known species of Neoclypeodytes. Distribution maps, illustrations of important morphological features and natural history notes are provided for each species. A single possible synapomorphy was found supporting the monophyly of Neoclypeodytes, a pattern of two maculae on each elytron. The perplexing and unresolved relationships of Neoclypeodytes to other bidessine genera are discussed. A cladistic analysis using twenty-two characters of adult morphology is presented for twenty-five species of Neoclypeodytes, with Uvarus lacustris (Say) and Liodessus affinis (Say) as outgroup taxa (rooted at U. lacustris). A single most parsimonious cladogram was obtained.