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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Sciviamonas

Sciviamonas Ekelund & Patterson, 1997 (ref. ID; 4907 original paper)

[ref. ID; 4907]
Diagnosis; Solitary, naked, phagotrophic protists with two heterodynamic flagella inserting subapically in a deep pocket. Movement a wobbling gliding. One flagellum directed anterior-laterally, the other trailing. Body pliable. Monotypic. (ref. ID; 4907)
Etymology; Composed of "Scientiarum" (Latin; science), "Via" (Latin; road), and "Monas" (derived from Greek; single). Neuter. (ref. ID; 4907)
Type species; Sciviamonas terricola sp. nov. (ref. ID; 4907)
  1. Sciviamonas terricola Ekelund, Patterson & Vors, 1997 (ref. ID; 4907 original paper)

Sciviamonas terricola Ekelund, Patterson & Vors, 1997 (ref. ID; 4907 original paper)

Diagnosis

Sciviamonas 2.5-4 um long. Anterior flagellum of about cell length, posterior flagellum about 1.5 times cell length. Site of food uptake anterior to but near site of flagella insertion. (ref. ID; 4907)

Descriptions

Cell outline roundish to ovate, D-shaped, compressed laterally, about one fifth as thick as long. Two heterodynamic flagella inserted subapically at an angle of about 70-90 degrees to anterior end of cell. Flagella taper at tips. Anterior flagellum approximately of cell length or slightly shorter, posterior flagellum 1.5 to 2 times cell length, trails. Cell truncate in profile, with depression where flagella leave cell. Flagella emerge from a broad pocket, which originates near centre of cell. Cell, in particular the area surrounding flagellar pocket, rich in granules, possibly extrusomes. Nucleus ventral, close to flagellar pocket. Contractile vacuole dorsal. Cells appear to be surrounded by mucilage, sometimes covered with adhering particles. Dividing cells with two trailing and one or two anterior flagella often observed. Cell glide in a wobbling manner, much like Heteromita globosa; posterior flagellum trails, anterior flagellum moves across substrate in front of cell, beat envelope covers an angle of about 150 degrees. Ingestion of bacteria seen in several cases. When anterior flagellum makes contact with a bacterium, the prey is moved towards the cell by the flagellum and taken up in the flagellar pocket just anterior to the site where the flagellum leaves the pocket. (ref. ID; 4907)

Comments

The nature of movement and the putative presence of extrusomes in Sciviamonas terricola suggest affinity with the cercomonads; in particular there is a great superficial resemblance to Heteromita globosa. However, the cell flattened cells and the deep flagellar pocket are features very different from those of H. globosa. Cells shape, extrusomes, and the subapically insertion of flagella resemble Discocelis (Vors 1988; Larsen & Patterson 1990), but this genus does not have a deep flagellar pocket. Metopion fluens (Larsen & Patterson 1990) also shares some similarities but differs because of its prominent, swollen anterior end. Sciviamonas terricola differs sufficiently from other flagellates that we are unable to assign it to any genus. Until more information has accumulated on the organism, it is placed in Protista incertae sedis. (ref. ID; 4907)

Type location

Cultivated garden soil, University of Sydney, New South Wales, Australia. (ref. ID; 4907)

Measurements

Length 2.5-4 um. (ref. ID; 4907)