The historical phylogeography of the two most important intermediate host species of the human blood fluke Schistosoma mansoni , B. glabrata in the New World, and B. pfeifferi in the Old World, was investigated using partial 16S and ND1 sequences from the mitochondrial genome. Nuclear sequences of an actin intron and internal transcribed spacer (ITS)‐1 were also obtained, but they were uninformative for the relationships among...