Spathidium Dujardin, 1841 (ref. ID; 2013, 3540)
Class Kinetofragminophora: Subclass Gymnostomata: Order Haptorida: Family Spathidiidae (ref. ID; 2013)
Family Spathidiidae Kahl in Doflein & Reichenow (ref. ID; 4813)

Synonym Spathidiosus Kahl, 1930 (ref. ID; 2013); Spathidiopsis Kahl, 1926 (ref. ID; 2013)

[ref. ID; 2013]
Body shape elongate, rounded in cross-section, posterior end bluntly pointed or rounded. Anterior region of body characteristically terminates obliquely but variable between transverse to longitudinal to the major body axis. There is always an ciliated apical ridge which is lined by trichocysts. The oral aperture is a slit lying along the length of the ridge. Ciliation uniform on both lateral surfaces in longitudinal parallel rows. Macronucleus highly variable, often elongate, ribbon-like or moniliform. Contractile vacuole single and terminal. Feeds on other ciliates. Originally described by Dujardin. (1841)
Quote; Colin R. Curds "British and other freshwater ciliated protozoa Part I Ciliophora: Kinetofragminophora" Cambridge University Press, 1982 (ref. ID; 2013)

Spathidium amphoriforme Greeff, 1888 (ref. ID; 1335, 1669, 3540, 3593) reported author and year? (ref. ID; 191, 7514)
Syn; Spathidium amphoriforme var. rectitoratum Kahl, 1930 (ref. ID; 3593); Spathidium amphoriforme var. securiforme Kahl, 1930 (ref. ID; 3593)
Description; The ultrastructural study. (ref. ID; 7514)
Spathidium muscorum Dragesco & Dragesco-Kerneis, 1979 (ref. ID; 4094) reported author and year? (ref. ID; 191)
Description; After protargol staining, distinctly sack-shaped, rarely slim. Oral bulge scalpel-shaped, approximately half of the body length. Somatic kineties meridional, with densely arranged kinetosomes. Brosse generally with 3, rarely with 4 rows. Angle between the somatic kineties and the perioral kinety on the left side greater than on the right. Basal body pairs of the perioral kinety arranged very densely. Nematodesmata bundled, about 30 um long. Macronucleus long and usually twisted, with many small, spherical nucleoli. (ref. ID; 4094)
[Cyst]: Spherical, with smooth cover surrounded by a 5-10-um-thick mucous layer. (ref. ID; 4094)
Spathidium seppelti Foissner, 1997 (ref. ID; 2846 original paper)
Diagnosis; Size in vivo about 80-140 x 20-40 um, spatulate. Oral bulge about one-third longer than maximum postoral width, inclined to ventral side, with eccentric depression. 100-200 macronuclear nodules. On average 21 somatic kineties. Terricolous. (ref. ID; 2846)
Description; Body narrowed behind oral bulge, posterior end more broadly rounded in impregnated than in living specimens; cross-section circular in mid-body, neck and oral bulge laterally distinctly flattened and rather flexible and hyaline. Oral bulge slightly to considerably inclined ventrally, with distinct conical depression in dorsal third; about one-third longer than maximum postoral width on average, anterior end thus distinctly set off from narrowed neck, appears obliquely truncate in living specimens but convex after protargol impregnation. About 100-200, usually 120-150 ellipsoidal to globular macronuclear nodules, each with one to two large (1-1.5 um in diameter) and some tiny (> 1 um) nucleoli. Micronuclei globular, irregularly distributed, number variable and often difficult to determine because of many similarly sized cytoplasmic inclusions. Contractile vacuole in rear end, with one to four excretory pores in posterior pole area. Extrusomes rod-shaped, 3-4 um long in vivo, found only in oral bulge. Pellicle colourless, slightly furrowed by ciliary rows; cortical granules 0.5 um in diameter, pale, arranged in two to three indistinct rows between each two kineties. Cytoplasm rather hyaline, contains some fat droplets (about 5 um across) and food vacuoles with ciliates (for example, hypotrichs); well-fed and thus rather opaque specimens filled with 8-10 um-sized, ellipsoidal to roundish inclusions. Moves rather fast in straight lines, changing direction frequently. Somatic kineties bipolar, rather loosely ciliated, those of right side about to circumoral kinety at acute angles, while those of left side, which have three of five narrowly spaced cilia at anterior end, abut at right angles. Dorsal brush three-rowed, rows 1 and 2 almost of same length and composed of narrowly spaced dikinetids having 3-4 um long, rod-shaped cilia; row 3 consists of a short, dikinetidal anterior portion with 3-4 um long cilia and a long, monokinetidal posterior tail having 2-4 um long bristles and terminating behind mid-body; all brush rows continue posteriorly as normal somatic kineties. Circumoral kinety continuous (not fragmented), composed of narrowly spaced dikinetids having long nematodesmata forming wedge-shaped bundles. (ref. ID; 2846)
Comments; The anterior portion of the left lateral kineties of S. seppelti does not duplicate the circumoral kinety. Thus, it belongs to the genus Spathidium. However, the eccentric conical indentation of the oral bulge is a very peculiar characteristic. Spathidium sp. found by Smith (1978) on sub-Antarctic and maritime Antarctic islands is probably conspecific with S. seppelti because, as indicated by the figure given, it is rather similarly sized and shaped and has, apparently, many macronuclear nodules. However, a definite identification is impossible because Smith's (1978) figure is not accompanied by a description. At first glance, S. seppelti resembles a small Epispathidium regium Foissner, 1984, which has, however, considerably more (average 41 vs. 21) and differently arranged somatic kineties (anterior ends strongly curved and thus duplicating circumoral kinety). With regard to the number of macronuclei, S. seppelti resembles S. meloforme Alekperov, 1983 (150-200 nodules) and S. chlorelligerum Kahl, 1930 (50-100 nodules). However, the former is broadly fusiform, has many more somatic kineties (75-80 vs. 18-25), and was found in rearing ponds of a sturgeon hatchery. The latter is distinguished from S. seppelti by the larger size (200-400 vs. 80-140 um), the longer extrusomes (10-12 vs. 3-4 um), the number of somatic kineties (40-50 vs. 18-25), and the possession of symbiotic algae. Spathidium seppelti greatly resembles S. bavariense Kahl, 1930. However, the oral bulge of S. bavariense turns back at the dorsal end and duplicates this section, making the dorsal portion twice as thick as the ventral one. Furthermore, S. bavariense has a distinctly lower number of macronuclear nodules (15-35 vs. 100-200) and a relatively shorter oral bulge than S. seppelti. The individuals found by Wenzel (1953) were only about 70 um long (his drawing indicates 95 um). Spathidium sp. found by Vuxanovici (1962) resembles S. seppelti in size, number of somatic kineties, and extrusomes. However, it is differently shaped (elongate drop-like), has only about 11 macronuclear nodules, and occurred in a lake. Spathidium multinucleatum Gellert, 1955 described without figure, matches S. seppelti in body size and number of somatic kineties, but differs by having long extrusomes (exact length, however, not given), distinctly fewer macronuclei (30-32), and a short, very slightly ventrally inclined oral bulge. Several other and sometimes very poorly described Spathidium species, such as Spathidium ampulliforme Sramek-Husek, 1954, S. armatum Vuxanovici, 1959, S. inflatum Vuxanovici, 1962, S. longicolum Vuxanovici, 1962, S. metabolicum Pompand & Wilber, 1988, S. nigrum Vuxanovici, 1959, S. plurinucleatum Andre, 1916, have a multinodular macronucleus, but differ considerably from S. seppelti at least in shape, size, extrusomes, and number of somatic kineties or macronuclear nodules. (ref. ID; 2846)
Spathidium spathula O.F. Muller, 1786 (ref. ID; 1619, 3115, 3540, 3593) reported year? (ref. ID; 1618, 3598, 3992, 4842) or (Mueller, 1786) Woodruff & Spenser, 1922 (ref. ID; 4488)
Description; The somatic ciliature of Spathidium spatula is arranged in 20-24 longitudinal kineties. Cilia originate from pits along the kinetal grooves. (ref. ID; 3992)
Measurements; Up to 250 um long. (ref. ID; 1618)