“…This period was also characterized by the establishment of new silver impregnation techniques for trichostomatid ciliates, such as the adaptations of ammoniacal silver carbonate impregnation proposed by Ito and Imai (1998) and Rossi et al (2016) and the adaption of Protargol's impregnation for vestibuliferids proposed by Ito and Imai (2000). These techniques allowed the development of several studies describing the infraciliature and morphogenetic process in different trichostomatid species (Ito et al, 1997(Ito et al, , 2001(Ito et al, , 2002(Ito et al, , 2008(Ito et al, , 2010(Ito et al, , 2011(Ito et al, , 2014(Ito et al, , 2017Ito and Imai, 1998, 2003Gürelli and Ito, 2014;Cedrola et al, 2016, Cedrola et al, 2017a,b, 2018aGürelli and Akman, 2016;Gürelli, 2018Gürelli, , 2019, which were very important to understand the evolutionary relationships within the Trichostomatia.…”