Crithidia, Leptomonas, Phytomonas, Herpetomonas, and Blastocrithidia. An early divergence within the trypanosome lineage led to separate salivarian (e.g., T. brucei) and nonsalivarian trypanosomes (Haag et al., 1998). One study further splits the nonsalivarian trypanosomes into two clades, consisting of bird trypanosomes, such as Trypanosoma avium, and stercorarian trypanosomes such as Trypanosoma cruzi (Haag et al., 1998).
The bodonid group is poorly studied and is probably paraphyletic (Wright et al., 1999). The rRNA tree in Fig. 1 includes multiple species from this lineage. The deepest branches of the bodonid lineage include the poorly studied free-living organisms Bodo designis, Rhynchobodo, and Dimastigella. This is followed by a mixed clade of free-living Bodo caudatus, Cryptobia helicis, and the parasitic Cryptobia salmositica and Trypanoplasma borreli. Another free-living organism, Bodo saltans, may represent the clos-