Genus: Postoral kineties usually to left of oral poykinetids (Illustrated Guide, 1985). Left edge is more curved than right edge; cytopharynx with numerous strong fibrils; ectoplasm with numerous fusiform trichocysts; macronucleus oval; one to several micronulei (Kudo, 1966).
Species: Cell body 60-80 μm long; macronucleus short sausage-shaped; a single micronucleus; a single contractile vacuole (Kahl, 1930).
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RAPD tree of Frontonia (Tsukii, Jpn. J. Protozool., vol. 36, 2002)
F. depressa
72 x 36 μm
Japan, 1998
Movies 
F. depressa
cysts, 32 μm
Japan, 1998
Movies 
F. depressa
Azure-C staining
88 x 60 μm
single Mic.
Japan, 1998
F. depressa
Azure-C staining
two Mic. ?
Saitama, 1999
F. depressa
65 x 38 μm
Fujioka
Tochigi, 2001
F. depressa
90 x 46 μm
near Konuma
Akagi mountain
Gunma, 2005
F. depressa
75 x 44 μm
Azami-ike 1
Norikura highland
Nagano, 2007
F. depressa ?
109 x μm
Kareki-numa
Nikko
Tochigi, 2008
DV images 
27-1B
μm
1 Mic.
Hiroshima, 199?
