On Conjugation BetweenEuplotes VannusO. F. Mueller andEuplotes MinutaYocom

Isolation and Structural Characterization of Two Water-Borne Pheromones from Euplotes crassus, a Ciliate Commonly Known to Carry Membrane-Bound Pheromones

“…The results reported here contradict this widely, albeit uncritically accepted view. Based on the knowledge that inter‐specific cross‐mating reactions are relatively common among Euplotes species (Kuhlmann and Sato 1993; Nobili 1964; Nobili, Luporini, and Dini 1978)—most likely in relation to their mating type systems of a “high‐multiple” and virtually “open” type (Dini and Nyberg 1993; Nobili et al 1978)—we screened in a largely unsystematic approach E. crassus strains available in our laboratories to assess whether some of them were able to induce homotypic mating pair formation not between cells of other E. crassus strains, but between cells of E. raikovi strains which we know to be able to secrete water‐borne pheromones and to form homotypic mating pairs in response to interactions with these pheromones (Luporini et al 1983).…”

Analysis of autapomorphic point mutations provides a key for the tangled taxonomic distinction of the closely related species, Euplotes crassus, E. minuta and E. vannus (Ciliophora, Euplotida)

“…In Tuffrau's revision, instead, E. crassus and E. vannus are described with precisely upturned body sizes, i. e. 100 _ 127 and 75 _ 97 µm, respectively, and unchanged body shapes ("Ovale allongé presque parfait" in E. crassus; "Irrégulièrment ovalisé, un peu étranglé sur la droite, au contraire faiblement élargi sur la gauche" in E. vannus), with the addition of new information on the presence of 10 (eight dorsal and two latero-ventral) kineties in E. crassus and nine (seven dorsal and two latero-ventral) kineties in E. vannus. Although the E. crassus and E. vannus body sizes and shapes reported by Kahl (1932) were fully validated by Heckmann (1963Heckmann ( , 1964 and Nobili (1964Nobili ( , 1965b in their genetic works on these species, the E. crassus and E. vannus descriptions by Tuffrau (1960) have earned much more reference since their tout court reiteration in the "Guide to Euplotes species" by Curds (1985). Not only has this reiteration consolidated cell-body sizes overturned between the E. crassus and E. vannus morphotypes.…”

“…The fixation of genetic boundaries delimiting E. crassus, E. minuta and E. vannus faces difficulties with a common capacity of various strains representative of each species to cross-mate, as well as form (albeit under laboratory conditions) hybrid (yet sterile) mating pairs (Nobili 1964(Nobili , 1965bNobili et al 1978), as also happens between other Euplotes sister species such as E. patella and E. octocarinatus Carter, 1972 (Kuhlmann andSato 1993). In coherence with this capacity, E.…”

“…crassus, E. minuta and E. vannus have been regarded, first, to form an 'Artenkreis' by Nobili (1964) and, then (along with E. mutabilis, a no longer valid species), a complex of sibling species within the monophyletic "vannus group of genus Euplotes" by Génermont et al (1976Génermont et al ( , 1985, in analogy with the sibling-species complexes proposed in Paramecium aurelia by Sonneborn (1975) and in Tetrahymena pyriformis by Nanney and McCoy (1976).…”