Genus Sappinia Dangeard, 1896
Diagnosis: Locomotive form resembles a smooth Thecamoeba, some 63 µm in length. Tendency for cells to have 1 to 4 pairs of nuclei. Mature cysts uninucleate or binucleate; life cycle of this amoeba thought to involve sexual processes in the cyst phase. One species reportedly has stalked cysts or resting stages.
At the ultrastructural level, surface coat as a thick glycocalyx.
Type species: Sappinia pedata Dangeard, 1896
Ecology: Widely distributed in freshwater, soil, and manure.
Sappinia pedata Dangeard, 1896
Diagnosis: Locomotive form monopodial lingulate ovate amoeba; surface often with a wrinkled appearance along the edges, without regular longitudinal dorsal ridges. Length of locomotive from (35) 45–65 (85) µm; breadth of locomotive from (16) 18–35 (42) µm; length/breath ratio 1.45–3.34 (mean 2.31). Trophozoites typically binucleate with closely apposed nuclei; although uninucleate, trinucleate, and tetranucleate amoebae may be observed, nuclei always paired when even numbers present. Each nucleus ca 4.5 µm in diam., typically with a single large central nucleolus ca 2.0 µm in diam.; pairs of nuclei ca 9.0 µm in width. Amoebae may form distinct clusters in culture and on tips of projections of natural substrates. Standing form clavate to spatulate, with a distinct narrowing toward the base, nearly colorless to very pale yellow with a slightly opaque refractive quality; height 55–79 µm; standing form not encysted, immediately motile when contacting substrate. Cysts round, 21–23 µm in diam., either bicellular when immature or unicellular when mature.
Ecology: Herbivore dung, decaying plant matter in the litter, standing decaying plant matter, soil, dog dung; Auckland Islands, Central Asia, Europe, Hawaiian Islands, Kenya, New Zealand, North America, Oman, South America, Thailand.
Reference: Brown, M., Spiegel, F.W. and Silberman, J.D. 2007. Amoeba at Attention: Phylogenetic Affinity of Sappinia pedata. J. Eukaryot. Microbiol., 54(6), pp. 511–519.