A Comparative Study of Three Fresh-Water Euplotes Species (Ciliophora, Hypotrichida)

Abstract

E. aediculatus, E. eurystomus and E. woodruffi, all having 9 frontoventral cirri and an eurystomus-type dorsal interkinetal system were compared in life, as well as with specimens prepared by picro-carmine nuclear stain, a silver impregnation technique, and nigrosin-HgCl2-formalin stain and fixative. Considered essential in separation of these species were number, distribution and spatial arrangement of ventral cirri; configuration of dorsal interkinetal network; shape of AZM [adoral zone of membranelles]; shape of interphase macronucleus; sculpturing of right buccal overture; and sculpturing of peristomial plate. Considered of no taxonomic value were number of dorsolateral kineties, number of cilia in dorsolateral kineties, sculpturing of dorsal surface, number of membranelles in AZM and overall body size. Evidence is presented supporting the validity of the first 6 characters and evidence for doubting the last 5. Based on the former set of characteristics, E. plumipes Stokes, 1884 and E. variabilis Stokes, 1887 are considered junior synonyms of E. eurystomus.