Heteronema Dujardin (ref. ID; 1618) or Stein (ref. ID; 3517), Dujardin, 1841 emend. Stein, 1878 (ref. ID; 4950)
Euglenida Butschli, 1884 (ref. ID; 4872)

[ref. ID; 1618]
Plastic; rounded or elongate; flagella arise from anterior end, one directed forward and the other trailing; cytostome near base of flagella; holozoic; fresh water. (ref. ID; 1618)

Heteronema acus (Ehrenberg) (ref. ID; 1618) or (Ehrenberg) Stein (ref. ID; 3342, 3517, 4950)
Description; Extended body tapers towards both ends; anterior flagellum as long as body, trailing one about one-half; contractile vacuole anterior; nucleus central; fresh water. (ref. ID; 1618)
Measurements; 40-50 um long. (ref. ID; 1618)
56 um. (ref. ID; 3342)
Heteronema mutabile (Stokes) (ref. ID; 1618) or (Stokes) Lemmermann (ref. ID; 4950)
Description; Elongate; highly plastic; longitudinally striated; in cypress swamp. (ref. ID; 1618)
Measurements; About 250 um long. (ref. ID; 1618)
Heteronema ovale Kahl, 1928 (ref. ID; 4872, 4950)
Description; Cell length 18 um, range 16-24 um. Cell broadly oblong to oblong with obtuse or slightly pointed ends, but able to contract to an almost circular profile and extend to an almost cylindrical profile. Approximately 25 thin pellicular stripes following a counter-clockwise helix, are similar on both faces of the cell. Wart-like refractile globules line the stripes. Cell capable of squirming which takes place infrequently but can be vigorous. Two flagella almost equal in length. Anterior flagellum about the length of the cell or slightly longer. Posterior flagellum thicker and about the length of the cell, capable of coiling when the cell is resting or adhering to surface. Mouth with obvious thick rods visible, nucleus located at the left ventral side immediately behind the centre of the cell. Cell swims in close contact with substrate or glides. (ref. ID; 4872)
Remarks; The lower end of the length range is below the range given by Larsen & Patterson (1990), and warts were not as numerous or as well developed. Consequently, the organisms observed here fall between H. exaratum and H. ovale as described by Larsen & Patterson (1990). Despite size similarity with H. exaratum and rather similar warts, the organisms are assigned to H. ovale because the grooving on the two faces of the cell is rather similar, but we feel that species identities in this area of the genus will require future attention. (ref. ID; 4872)
Heteronema scabra Z. Cyrus, 1958 (ref. ID; 3409 original paper)
Description; The cells lively moving, in stretched state oblongly lancelike, more or less sexangular. The anterior end of the cell is prolonged and moderate snoutlike enlarged, the posterior end being pointed. At the shrinking the size of body is changed into baglike till dishlike, the anterior part being more or less without change. The swimming flagellum is straight as long as the prolonged cell, the dragged flagellum as long as 1/3 of the cell or entirely very short. The surface of the cell is irregularly rugged, rough and it covers nearly all details of inner structure. The nutrition is animal-like and cells of green alga Oocystis were observed in its body. The motion is creeping. (ref. ID; 3409)
Measurements; Length of cell 35 um, width 14 um. (ref. ID; 3409)
Heteronema splendens Larsen & Patterson, 1990 (ref. ID; 4872)
Description; Cell length 120-130 um. Cell metabolic, covered with pericular stripes following a counter-clockwise helix. Stripes consist of ridges that have some swollen and some more narrow sections. Two flagella of unequal length emerge form the anterior end of a long flagellar reservoir and canal which is located in the first quarter of the cell. Anterior flagellum 40-45 um long, 0.8 um wide, extended when the cell is gliding. Posterior flagellum 55-60 um, trailing. Both flagella are slightly swollen at the base. Mouth with two rods, nucleus located close to the centre of the cell. No mucocysts attached to the stripes. (ref. ID; 4872)
Remarks; Larsen & Patterson (1990) base the identity of H. splendens on only one cell, and reported the size to be about 200 um. However, the size of the cell in the type micrograph is only about 140 um according to the scale bar, and we conclude that the two observations are of the same species. The lack of mucocysts argues against conspecificity and further investigation is required. (ref. ID; 4872)