Resting cyst in vivo

Description:

Resting cyst of the colpodid ciliate, Exocolpoda augustini (Foissner, 1987) Foissner, Agatha and Berger, 2002. Foissner erected the family Exocolpodidae based on the life cycle of its members, namely, cell division in free-swimming individuals instead of reproduction in division cysts as seen in the Colpodidae. He felt this life cycle characteristic,the unique boomerang-shaped left oral polykinetid and the unique thick-walled resting cyst of this species warranted its transfer to the new genus, Exocolpoda. The cyst is of the "cucullus" type the wall of which consists of closely spaced membranes.The cyst wall is further differentiated into a thin meso- and endocyst layer and the much thicker ectocyst layer. Dark granular material is scattered between the membranes of the ectocyst. Foissner believes the thick walled cyst may be an adaptation to the desert and semi-desert habitats where this species is most often found.Collected near Boise, Idaho (43°38'21.10"N 116°11'10.78"W elev. 2908 ft.) from aan ice-covered temporary puddle containing leaf litter and dead grass.November, 2005.Phase contrast.