Molecular Phylogeny and Species Delimiting for the Genus Hoplolaimus (Nematoda: Tylenchida) with Description of Hoplolaimus floridensis sp. n. and Notes on Biogeography of the Genus in the United States

Lance nematodes, <i>Hoplolaimus</i> spp., feed on the roots of many kinds of plants, including agronomic crops. In this study, morphological and molecular analyses of several <i>Hoplolaimus</i> species and populations are provided. We were able to collect and characterize the topotype materials of <i>H. galeatus</i> from Arlington, Virginia; <i>H. stephanus</i> syn. n. from Nichols, South Carolina; and <i>H. concaudajuvencus</i> from Pensacola, Florida, and several additional populations and species from the United States, Israel, and India. Phylogenetic analyses of several hundred sequences of the D2-D3 expansion regions of 28S rRNA, ITS rRNA, and COI genes of <i>Hoplolaimus</i> species obtained from published and original datasets were given. Fifty-three new D2-D3 of 28S rRNA, 43 new ITS rRNA, and 47 new <i>COI</i> sequences from 23 isolates of <i>Hoplolaimus</i> spp. and one isolate of <i>Peltamigratus christiei</i> were obtained in this study. New molecular identities for <i>H. concaudajuvencus</i> and <i>H. galeatus</i> were proposed. <i>Hoplolaimus stephanus</i> syn. n. was considered a synonym of <i>H. galeatus</i> based on the morphological and molecular similarity of these two species. Analysis of morphology and molecular data did not reveal significant differences among <i>H. columbus</i> syn. n., <i>H. indicus</i> syn. n., and <i>H. seinhorsti</i>, and the first two species were synonymized with <i>H. seinhorsti</i>. A new species, <i>H. floridensis</i> sp. n., was described from many locations in Florida, USA. It was separated from other representatives of the genus <i>Hoplolaimus</i> by its morphological and molecular characteristics. Maps with geographical distribution of several lance nematode species in North America were reconstructed based on published and original molecular identification of samples.