A cigar-shaped, heavily ciliated protoctist, 100–150 micrometers long, living in still or running fresh waters. Paramecium aurelia consists of a group of 14 syngens. Each syngen is genetically isolated from every other syngen and is also biochemically unique. However, all syngens are so similar morphologically that they have not been given individual species names. Each syngen has two mating types. Mating types were first discovered in syngen 1. See Classification, Protoctista, Ciliophora; Chronology, 1937, Sonneborn; 1971, Kung; conjugation, killer paramecia.
Subjects: Genetics and Genomics.