tRepresentatives of the genus Trypanosoma have been traditionally found in epimastigote, espheromastig-ote and trypomastigote flagellated forms in axenic cultures. Trypanosoma caninum is a trypanosomatidthat has recently been reported infecting dogs in endemic areas of canine leishmaniasis in Brazil. Itpresents specific biological characteristics and it is found exclusively on healthy skin. Here, we describethe evolutive forms of this parasite showing not only the forms commonly found in culture, but alsoepimastigote forms with no free flagellum. The study was conducted using scanning and transmissionelectron microscopy and, we demonstrate that typical flagellated epimastigotes originate from formswithout flagellum, although the latter may remain without differentiation in the culture. Two hypothesesare considered and discussed in this paper: (i) the aflagellated epimastigotes are a typical developmentalforms of T. caninum and (ii) the emergence of these aflagellated forms could be resultant from a disturbedprocess during cell division caused by interfering specific proteins, which leads to inability to form andregulate the flagellum length. In any case, considering that T. caninum is a parasite that is still little stud-ied, the information brought by our study adds data which may be useful to clarify aspects on the cellcycle of this intriguing parasite that has been found in different regions of Brazil.