Search for clues to the evolutionary meaning of ciliate phylogeny.

Progress in ciliatology and in allied fields may demystify ciliate phylogenetics. Concentration on hymenostomes (mainly Tetrahymena and Paramecium) may have obscured directional features of ciliate physiology in phylogenetic problems. Therefore, means are suggested for "domesticating" the presumptively primitive, predominantly marine, sand-dwelling gymnostomes having nondividing macronuclei. The prize quarry is the marine psammophile Stephanopogon whose homokaryotic condition may mark it as a living fossil. Eventual axenic cultivation of these "primitive" ciliates may be aided by use as food of easily grown photosynthetic prokaryotes, some isolated from the marine sulfuretum or adjacent aerobic muds and sands where "karyorelictid" ciliates flourish.