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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Thaumatomastix

Thaumatomastix Lauterborn, 1899 (ref. ID; 7130)

Family Thaumatomonadidae Hollande, 1952 (ref. ID; 7130)

[ref. ID; 1618]
Colorless; pseudopodia formed; 2 flagella, one extended anteriorly, the other trailing; holozoic; perhaps a transitional form between the Mastigophora and the Sarcodina. One species. (ref. ID; 1618)

[ref. ID; 7130]
Revised diagnosis; Unicellular, non-colonial, biflagellate thaumatomonads with long spine scales (no flagella observed in Tx. patelliformis or tauryanini, two of three species known only from very few specimens on electron microscope whole mounts); triangular or oval two-tiered body scales also present (except type species ultrastructure unknown, so no evidence for plate scales). PF longer than body; after emerging from apical flagellar pocket bent backwards, used for gliding on surfaces; AF rather short except in Tx. setifera (in Tx. salina bears small elongated oval flagellar scales, often somewhat pointed at ends); pseudopodia reported only in Tx. setifera and tripus. Phagotrophs, some algivorous. (ref. ID; 7130)
Comments; This restricts Thaumatomastix to six species (four marine, two freshwater) with spine scales (at least two more unnamed ones exist with unique oval scales: Thomsen et al. 1993): Tx. setifera, salina, tripus, which all have ventral grooves and glide on their long smooth posterior flagellum (Beech and Moestrup 1976), and Tx. patelliformis, bipartita and tauryanini, which have never been seen alive and whose locomotory mode is unknown. Transfer of the biflagellate freshwater colonial Chrysophaerella triangulata (Balanov 1980) to Thaumatomastix (Beech and Moestrup 1976) was wrong; Balanov called its longer anterior flagellum pinnate, feathery or plumose (in both Latin and Russian: i.e. evidently a hairy or tinsel heterokont flagellum) and described a profoundly dissected single chromatophore and stigma, but no groove. All four character decisively contradict assignment to Thaumatomastix; its lateral flagellum is much shorter (opposite to Thaumatomastix) and Balanov observed neither gliding nor pseudopods. He studied body scales and flagella by electron microscopy (reporting no AF scales); spine scales have a basal bobbin-like structure more similar to that of Chrysosphaerella brevispina Beech and Moestrup (1976) than the less symmetric one of C. longispina, with a much broader distal disc than the narrow distal discs of Tx. salina, tripus, bipartita and T. patelliformis (Beech and Moestrup 1976), or Tx. tauryanini (Mikrjukov 2002). As there are nine unambiguous differences from Thaumatomastix, C. triangulata was clearly a synurid chrysomonad with novel triangular plate scales as well as spine scales, just as Balonov thought; its coloniality and basal spine structure both make it a Chrysosphaerella not a Spiniferomonas. (ref. ID; 7130)
Type species; Thaumatomastix setifera Lauterborn, 1899 (ref. ID; 7130)
  1. Thaumatomastix bipartita Beech & Moestrup, 1986 (ref. ID; 7507) reported author and year? (ref. ID; 7130)
  2. Thaumatomastix dybsoena Thomsen et al., 1993
    See; Reckertia dybsoena (ref. ID; 7130)
  3. Thaumatomastix formosa Thomsen et al., 1993
    See; Reckertia formosa (ref. ID; 7130)
  4. Thaumatomastix fragilis Thomsen et al., 1995
    See; Reckertia fragilis (ref. ID; 7130)
  5. Thaumatomastix fusiformis Thomsen et al., 1995
    See; Reckertia fusiformis (ref. ID; 7130)
  6. Thaumatomastix groenlandica Thomsen & Ikavalko, 1995
    See; Reckertia groenlandica (ref. ID; 7130)
  7. Thaumatomastix igloolika Thomsen & Ikavalko, 1995
    See; Reckertia splendida (ref. ID; 7130)
  8. Thaumatomastix nigeriensis Wujek, Pershon & Kadiri, 2008
    See; Reckertia nigeriensis (ref. ID; 7130)
  9. Thaumatomastix patelliformis (ref. ID; 7130)
  10. Thaumatomastix salina (ref. ID; 7130, 7507)
  11. Thaumatomastix setifera Lauterborn, 1899 (ref. ID; 7130) reported year? (ref. ID; 1618, 3497)
  12. Thaumatomastix spinosa Thomsen et al., 1993
    See; Reckertia spinosa (ref. ID; 7130)
  13. Thaumatomastix splendida Thomsen et al., 1995
    See; Reckertia splendida (ref. ID; 7130)
  14. Thaumatomastix tauryanini (ref. ID; 7130)
  15. Thaumatomastix tripus (ref. ID; 7130)

Thaumatomastix bipartita Beech & Moestrup, 1986 (ref. ID; 7507) reported author and year? (ref. ID; 7130)

Descriptions

TEM: Only isolated spineless scales were observed in the TEM preparations, but the structure of these scales clearly identified them as belonging to a species of Thaumatomastix. The elliptical shape, unornamented cross partition, and single row of perforations in the margin of the scale plate all are diagnostic features of T. bipartita (Beech & Moestrup 1986), and the scales therefore are referred to this species. (ref. ID; 7507)

Remarks

T. salina has spineless scales resembling those of T. bipartita. The spineless scales as multiple rows of perforations at the margin of the scale plate, and more perforations scattered throughout the scale plate than does T. bipartita. However, some T. salina specimens have spineless scales that are difficult to distinguish from those of T. bipartita (Takahashi & Hara 1984; Beech & Moestrup 1986). The possibility that the Lake Waihola organism represents such a specimen of T. salina, or is a new species closely related to both T. salina and T. bipartita, cannot be excluded entirely in the absence of observations on its spine scales, flagellar scales or protoplast. Thaumatomastix bipartita has been reported previously only from cool (12 degrees C), brackish (14 ppt salinity) water in the Isefjord, Denmark (Beech & Moestrup 1986). Thaumatomastix salina is more widely distributed, including record from New Zealand marine waters (Moestrup 1979), and is known to be both eurythermal (4.4-21.5 degrees C) and euryhaline (3-35 ppt) (Beech & Moestrup 1986). Although Lake Waihola is tidally influenced, previous studies suggest that the level of seawater incursion into this lake is rarely, if ever, sufficient to raise the salinity to levels as high as 3ppt at the site were T. bipartita was obtained (Mitchell & Edwards 1988). The Lake Waihola organism is correctly referred to T. bipartita, the new record suggests that the ditribution, as well as the ecology, of T. bipartita are similar to those of the presumed close relative T. salina, and that both species may be found in suitable freshwater habitats. (ref. ID; 7507)

Examined material

Lake Waihola (New Zealand Map Series grid reference 260-H45-847623; latituda 46 degrees 1'S, longitude 170 degrees 5'E) is a tidally-influenced eutrophic freshwater lake in the South Island of New Zealand. Plankton samples were collected on 30 December 1988, from a jetty opposite the town of Waihola, with a handheld 10 um mesh plankton net. Surface water temperature at the site was 20.5 degrees C. (ref. ID; 7507)

Thaumatomastix setiferaLauterborn, 1899 (ref. ID; 7130) reported year? (ref. ID; 1618, 3497)

Descriptions

In fresh water. (ref. ID; 1618)
The flat elliptical body has two flagella, a forward swimming as long as a cell and a posterior trailing flagellum about twice as long as body, a large reservoir in the anterior portion and many ovoidal chromatophores. The nucleus is usually in the posterior half of the body. On the surface numerous radial thread-like spines are projecting from the periplast, a longitudinal wide line runs along the middle of the ventral side. (ref. ID; 3497)

Measurements

About 20-35 by 15-28 um. (ref. ID; 1618)
Length 17-33 um; breadth 10-23 um. (ref. ID; 3497)