Parablepharisma was part of the family, but more careful inspection (morphological and molecular) has placed it in a separate class distinct from the heterotrichs.[3] Acquisition of ribosomal sequences from Pseudoblepharisma in 2021 and 2022 also produces phylogenetic results incongruent with current taxonomy, instead placing the genus sister to Spirostomum.[4]
^Chi, Yong; Chen, Xiangrui; Li, Yuqing; Wang, Chundi; Zhang, Tengteng; Ayoub, Alex; Warren, Alan; Song, Weibo; Wang, Yuanyuan (1 April 2021). "New contributions to the phylogeny of the ciliate class Heterotrichea (Protista, Ciliophora): analyses at family-genus level and new evolutionary hypotheses". Science China Life Sciences. 64 (4): 606–620. doi:10.1007/s11427-020-1817-5. PMID33068287. S2CID223558791.
^Campello-Nunes, Pedro H.; Fernandes, Noemi M.; Szokoli, Franziska; Fokin, Sergei I.; Serra, Valentina; Modeo, Letizia; Petroni, Giulio; Soares, Carlos A. G.; Paiva, Thiago da S.; Silva-Neto, Inácio D. da (2020-04-01). "Parablepharisma (Ciliophora) is not a Heterotrich: A Phylogenetic and Morphological Study with the Proposal of New Taxa". Protist. 171 (2): 125716. doi:10.1016/j.protis.2020.125716. ISSN1434-4610. PMID32086115. S2CID211246127.