Systematic review of the genera Rhabdostyla Kent 1880 and Orborhabdostyla Foissner et al. 2010 (Ciliophora, Peritrichia, Epistylididae) Author Souza, Pedro Mendes De ¹ Laboratório de Protozoologia, Programa de Pós-Graduação em Biodiversidade e Conservação da Natureza, Universidade Federal de Juiz de Fora, Martelos, 36036 - 900, Juiz de Fora, Brazil Author Rossi, Mariana Fonseca ¹ Laboratório de Protozoologia, Programa de Pós-Graduação em Biodiversidade e Conservação da Natureza, Universidade Federal de Juiz de Fora, Martelos, 36036 - 900, Juiz de Fora, Brazil Author Dias, Roberto Júnio Pedroso ¹ Laboratório de Protozoologia, Programa de Pós-Graduação em Biodiversidade e Conservação da Natureza, Universidade Federal de Juiz de Fora, Martelos, 36036 - 900, Juiz de Fora, Brazil text Zootaxa 2024 2024-01-12 5399 3 201 230 http://dx.doi.org/10.11646/zootaxa.5399.3.1 journal article 10.11646/zootaxa.5399.3.1 1175-5326 10516774 2134D857-542C-40A6-9557-CB8E042E4271 Rhabdostyla dubia Foissner 1979 — Fig. 2 , O Diagnosis: Size about 30–35µm. Body from a vessel-like form to a funnel-like, when contracted assumes a pear shape with a bifurcated peristomial disc with clear transverse striations on the pellicle. Peduncle measures 2–5 µm, with transverse striations and grooves, usually enlarged at the base. Contractile vacuole found just below the peristomial collar, on the ventral wall of the, wide and quite short, vestibule. Horseshoe-shaped macronucleus, inclined longitudinally. Ciliary of the adoral spiral long and robust. Cytoplasm with large and slightly yellowish granules. Silverline pattern resembles that of Pseudocarchesium erlangensis . Found on ostracods. Remarks: diagnosis based on ( Foissner 1979b ). He reports for the species cysts with about 30 µm in diameter, ectocysts with numerous mole-shaped elevations. The author also highlights that the position of the contractile vacuole and the form of contraction are the characteristics that distinguish R. dubia from other very similar species, R. ovum Kent, 1882 , R. cyclopis Kahl, 1935 and R. ovum var. culiciidarum Nenninger, 1948 . According to him, it is possible that these 4 species are just an expression of the great variability of a species, especially if we assume that Kahl (1935) and Nenninger (1948) wrongly drew the contractile vacuole on the dorsal wall of the infundibulum.