New genera, species, and improved phylogeny of Glissomonadida (Cercozoa).

Glissomonadida is an important cercozoan order of predominantly biflagellate gliding bacterivores found largely in soil and freshwater. Their vast diversity is largely undescribed. We studied 23 mostly newly isolated strains by light microscopy and sequenced their 18S rDNA genes; nine represent new species. For two misidentified ATCC 'Heteromita triangularis' strains, we establish novel gliding genera and species: the sandonid Mollimonas lacrima, the only glissomonad forming anterior and posterior pseudopodia, and Dujardina stenomorpha, a strongly flattened member of the new family Dujardinidae. A new strain from Oxfordshire grassland soil is the first reliably identified isolate of the virtually uniflagellate, smooth-gliding glissomonad genus, AllantionSandon, 1924. Phylogenetic analysis and cytological features reveal Allantion to be a member of Allapsidae. Sandona limna and Bodomorpha prolixa from Lake Baikal and Sandona hexamutans from volcanic Costa Rican soil are described as new species. Fifteen glissomonad strains were from grassland beside Lake Baikal. We describe two as new species of Sandona (S. heptamutans and S. octamutans); the others included strains of Sandona and Allapsa species that have already been described; and three were new species of Sandona and Allapsa but these died before being described. We discuss the ecological and evolutionary significance of these new strains.