Molecular characterization and taxonomy of a new species of caudosporidae (Microsporidia) from black flies (Diptera: Simuliidae), with host-derived relationships of the North American caudosporids

Anew species of microsporidium, Caudospora palustris (Microsporidia: Caudosporidae), is described from 3 species of black dies (Cnephia ornithophilia and diploid and triploid cytospecies of Stegopterna mutata), bringing to 7 the total species of caudosporids recorded from North America. This new species of caudosporid is recorded from swamp streams of the Coastal Plain from New Jersey to Georgia, with single records from the New Jersey mountains and the Upper Peninsula of Michigan. Densities of patently infected larvae (up to 10,600/m(2)) and spore production (nearly 8 x 10(11)/m(2)) are the greatest recorded for any microsporidium of black flies. The ultrastructure of this new species is presented, along with the first molecular characterization for a microsporidium of black flies. The phylogenetic position of black fly microsporidia within the phylum Microsporidia is presented; however, the analysis does not support the inclusion of C. palustris in any clade, Key features of all North American caudosporids are provided, and possible evolutionary trajectories are proposed based on optimization of caudosporid species on the phylogeny of their 22 known host species, including 16 that represent new host species records.;(C) 2000 Academic Press.