ISSN (print) 0093-4666 © 2011. Mycotaxon, Ltd. ISSN (online) 2154-8889 MYCOTAXON http://dx.doi.org/10.5248/118.433 Volume 118, pp. 433–440 October–December 2011 Homolaphlyctis polyrhiza gen. et sp. nov., a species in the Rhizophydiales (Chytridiomycetes) with multiple rhizoidal axes Joyce E. Longcore 1 *, Peter M. Letcher 2 & Timothy Y. James 3 1 School of Biology & Ecology, University of Maine 5722 Deering Hall, Orono, ME 04469-5722, USA 2 Department of Biological Sciences, he University of Alabama Box 870344, Tuscaloosa, AL 35487 USA 3 Department of Ecology & Evolutionary Biology, University of Michigan 830 North University, Ann Arbor, MI 48109-1048 USA * Correspondence to: longcore@maine.edu Abstract — An undescribed cellulosic chytrid with multiple rhizoidal axes, JEL142, has grouped in molecular hypotheses with Batrachochytrium dendrobatidis, the chytrid pathogen of amphibians, and thus is of interest for genetic and physiological comparisons. To describe this member of the Rhizophydiales, we examined its zoospore ultrastructure and developmental morphology. Based on a reanalysis of rDNA data plus ultrastructural and morphological characters, we name this fungus Homolaphlyctis polyrhiza gen. et sp. nov. Key words — Chytridiomycota, phylogeny, Rhizophlyctis, TEM Introduction A chytrid referred to by its isolate number, JEL142, has been in phylogenies since the first molecular hypotheses of the Chytridiomycota (James et al. 2000, 2006; Letcher et al. 2008b) but has not been identified to species or received a formal name. his isolate is of interest because it groups as sister to Batrachochytrium dendrobatidis Longcore et al. (Longcore et al. 1999), the pathogen of amphibians, and because it is one of the few members of the Rhizophydiales Letcher (Letcher et al. 2006) that have thalli with multiple rhizoidal axes. Although the phylogenetic distance based on branch lengths in phylograms is large and support values for the relationship have been low (James et al. 2006; Letcher et al. 2008b), JEL142 seems to be the closest relative to B. dendrobatidis now in culture. In an effort to identify genes that enable