LEARAMOEBA-WACCAMAWENSIS, N-G, N-SP (HETEROLOBOSEA, VAHLKAMPFIIDAE), A NEW TEMPERATURE-TOLERANT CYST-FORMING SOIL AMEBA

Soil from a roadside ditch at Lake Waccamaw, North Carolina, was teste d for cyst-forming free-living amoebae, and water from the same ditch was tested for fecal coliform bacteria. Soil samples incubated at room temperature (21-23 degrees C) yielded Acanthamoeba polyphaga, Amoeba sp., Hyperamoeba sp., Mayorella penardi, Naegleria gruberi, Naegleria minor, and unidentified ciliates, testaceans and slime molds. Incubati on at 37-39 degrees C yielded Acanthamoeba jacobsi, Platyamoeba schaef feri, and a new amoeba to be described herein. Fecal contamination of the ditch was confirmed by a direct membrane filtration technique that yielded a mean of 1,410 +/- 134 bacteria/ml. The new amoeba is assign ed to the class Heterolobosea Page & Blanton, 1985 on the basis of pro mitotic nuclear division, and a flagellated stage with a cytostome as seen in the genus Tetramitus. Amoebae studied in hanging drop preparat ions were flattened and irregular as described for the genus Stachyamo eba in the family Gruberellidae but changed to a lobose cylindrical fo rm as described for species of Vahlkampfia in the family Vahlkampfiida e. A new genus and species, Learamoeba waccamawensis, is proposed for the amoeba described herein.