Genus: Highly flattened; pellicle firm; body form constant (Kudo, 1966). Chloroplasts small, discoid, pyrenoids usually absent; most species flat and leaf-shaped; often with ridges or fins running helically or longitudinally (Illustrated Guide, 1985).
Species: 120-170 μm long, 45-70 μm wide; usually slightly twisted; a long caudal prolongation; flagellum about 1/2 body length; stigma prominent; a discoidal paramylon (paramylum) body central; pellicle longitudinally striated (Kudo, 1966).
var. longicauda: cell body 85-170 μm long, 45-70 μm wide; locomotive flagellum shorter than the cell body; a single paramylon body ring shaped (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).
Google Image Search
Tail long
P. longicauda
body, 90 x 56 μm
tail, 60 μm
near Mihashi Park
Saitama, 2006
P. longicauda
body, 84 x 58 μm
tail, 77 μm
Japan, 199?
P. longicauda
body, 75 μm
tail, 65 μm
Sakitama-kofun p.
Gyoda
Saitama, 2004
P. longicauda
body, 73 μm
tail, 71 μm
Uruguay, 1999
P. longicauda
body, 70 μm
tail, 77 μm
near Town Hall
Shobu
Saitama, 2004
P. longicauda
body, 155 μm
tail, 70 μm
Iyari marsh
Omachi
Nagano, 2007
P. longicauda
body, 64 μm
tail, 71 μm
Uruguay, 1999
P. longicauda
body, μm
tail, μm
Japan, 199?
P. longicauda
body, 61 μm
tail, 48 μm
Takasaka
Saitama, 2002
P. longicauda
body, μm
tail, μm
Iruma
Saitama, 2003
P. longicauda
body, 48 μm
tail, 50 μm
water reservoir
near Yamaguchi Univ.
Yamaguchi, 2004
P. longicauda
body, 50 μm
tail, 30 μm
Izumo Shrine
Izumo
Shimane, 2006
P. longicauda
body, μm
tail, μm
Nogyo Fureai p.
Toride
Ibaraki, 2008Tail short
P. longicauda, x 400
body, 81 x 60 μm
tail, 61 μm
Japan, 199?
P. longicauda, x 400
body, 80 x 50 μm
tail, 48 μm
Japan, 199?
P. longicauda ?
body, 55 μm
Mihashi Park
Saitama, 2002Cell body elongated
P. longicauda
body, 84 x 59 μm
tail, 60 μm
Saitama, 1999