Excavata Thomas Cavalier-Smith in 2002
Excavata are unicellular organisms, containing a variety of free-living and symbiotic forms, and also including some important parasites of humans. They are classified based on their flagellar structures, and they are considered to be the oldest members of flagellated organisms.
Arcella marginata, after Deflandre, 1929 Arcella marginata Daday, 1905 Diagnosis: Shell roughly hemispherical, rather overhanging, with a flattened, smooth edge. In dorsal view showing a
Arcella lobostoma, after Deflandre, 1929 Arcella lobostoma Deflandre, 1929 Diagnosis: Shell hemispherical. In ventral view, irregular circular outline, often a little elliptical; pseudostome irregularly lobed:
Pelomyxa palustris Pelomyxa palustris, found below decaying leaves in the hollow of a beech Pelomyxa palustris, found below decaying leaves in the hollow of a
H. galeata – from Stepanek, 1963 Hoogenraadia galeata (Stepanek, 1963) n. comb. Gillardella galeata Stepanek, 1963 Diagnosis: Shell somewhat similar to the shell of Corythion dubium
Arcella grospietschi, after Stepanek, 1963 Arcella grospietschi Stepanek, 1963 Diagnosis: Shell disc-shaped, yellow-brown, in ventral view with a undulated border, with seven large and seven smaller
Arcella oyei, after Stepanek, 1963 Arcella oyei Stepanek, 1963 Diagnosis: In dorsal view, the shell is circular, with 10 apparent broken lobes on the surface. In