TY - JOUR T1 - Systematic relationships of Nematomorpha based on molecular and morphological data JF - Invertebrate Biology Y1 - 2002 A1 - Bleidorn, C A1 - Schmidt-Rhaesa, A A1 - Garey, JR SP - 357 EP - 364 KW - Gordiida KW - Nectonema KW - Nematoda KW - phylogeny AB - We sequenced the 18S rRNA gene from 11 nematomorph species from 9 genera and derived hypotheses concerning the sister group of Nematomorpha and relationships within this taxon. The molecular and morphological data are consistent with the monophyly of Nematomorpha, a sister-group relationship between Nematomorpha and Nematoda, and a sister-group relationship between the marine genus Nectonema and all of the freshwater taxa, Gordiida. Hypotheses of relationships within Gordiida support the traditional taxa Gordiidae, Chordodidae, and Chordodinae but reject Paracbordodinae and Spinochordodidae. The molecular results differ from those of previous morphological studies by suggesting a reduction of the two tail lobes at the posterior end of males in Chordodinae, monophyly of the genus Paragordionus, and paraphyly of the genus Chordodes. PB - AMER MICROSCOPICAL SOC CY - 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 USA VL - 121 ER -