The major morphological classes of trypanosomatids.

Diagrams of six common, easily distinguished trypanosomatid morphologies [3]. A. Morphologies with a flagellum laterally attached to the cell body. B. Morphologies with a free flagellum (no lateral attachment of the flagellum to the cell body extending beyond the flagellar pocket neck). Metrics used to record cell morphology are indicated (cell body length, free flagellum length, kinetoplast–posterior distance (KP) and nucleus–posterior distance (NP)). Genera in which each morphology occurs [28] in are indicated, monophyletic genera [25] are underlined. C. Amastigote morphology, which does not have a long, motile, flagellum. D. Key. Structures associated with the flagellum (the basal body/pro-basal body pair (BB), flagellar pocket (FP), Axoneme (Ax) and paraflagellar rod (PFR)) are indicated.