Tetrahymena Furgason, 1940

[ref. ID; 2014]
Small to medium ciliate, ovoid to pyriform with anterior end narrowed. Oral aperture small in anterior body third, pyriform in outline with its axis parallel to that of the major body axis. There is an undulating membrane on the right and 3 small inconspicuous membranelles on the buccal cavity leads to the splitting of these membranelles such that 5 or 6 membranelles may be found; similar splitting of the membranelles has been noted in some microstomes (Kaczanowski, 1975). Macrostome formation allows the cell to lead a carnivorous way of life. Somatic ciliation complete with a straight pre-oral suture. Some rarely with a caudal cilium. Single terminal contractile vacuole. Macronucleus spherical centrally positioned. Elliott (1973). A recent paper by Nanny and McCoy (1976) has divided organisms previously known as Tetrahymena pyriformis into 14 species.
Quote; Colin R. Curds, Michael A. Gates and David McL. Roberts "British and other freshwater ciliated protozoa Part II Ciliophora: Oligohymenophora and Polyhymenophora" Cambridge University Press, 1983 (ref. ID; 2014)


Tetrahymena bergeri Roque, de Puytorac & Savoie (ref. ID; 3789) reported author and year? (ref. ID; 191)
Description; Tetrahymena rostrata-complex. Histophagous ciliate. (ref. ID; 3789)
Tetrahymena corlissi Thompson, 1955 (ref. ID; 3789) reported year? (ref. ID; 3698) reported author and year? (ref. ID; 65, 191)
Description; Tetrahymena rostrata-complex. Histophagous ciliate. (ref. ID; 3789)
Tetrahymena elliotti Nanney & McCoy, 1976 (ref. ID; 6884) reported author and year? (ref. ID; 65, 3882, 4035)
Remarks; Previously T. pyriformis GL, phenoset B, of Borden et al. 1973; strain L1630/1c of the Culture Centre of Algae and Protozoa, Cambridge, England. (ref. ID; 6884)
Tetrahymena limacis (Warren) (ref. ID; 1618, 3789) reported author and year? (ref. ID; 65)
Description; In liver and other visceral organs of the slug Deroceras reticulatum; the parasitic phase is cucumber-shaped with apiculate anterior end; the free-living organisms are pyriform, somewhat pointed anteriorly; cytostome at about one-fourth from the anterior end, with an undulating membrane and three membranelles; 32-40 ciliary rows (Kozloff, 1946). As was mentioned above, experimentally T. pyriformis can infect slugs without changing morphological characteristic except the size. The ciliate was further found in terrestrial gastropods, Monadenia fidelis and Prophysaon andersoni. Corllis (1952) held that Kozloff's form is different from T. limacis and called it T. faurei. (ref. ID; 1618)
See Tetrahymena rostrata-complex (ref. ID; 3789)
Measurements; 33-68 (55) by 18-35 (27) um; those from cultures measure 28-68 (44) by 17-42 (27) um. (ref. ID; 1618)
Tetrahymena patula (Ehrenberg, 1830) Corliss, 1951 (ref. ID; 3959) reported year? (ref. ID; 1335, 1618, 2100)
Syn; Leucophrys patula Ehrenberg (ref. ID; 1618)
Description; Broadly pyriform; occasionally small forms occur; cytostome pyriform, about one-third the body length; 40-45 ciliary meridians; macronucleus irregularly ovoid; a micronucleus attached to micronucleus; carnivorous, but may be cultured in sterile media; fresh water. (ref. ID; 1618)
Measurements; 80-160 um long. (ref. ID; 1618)
Tetrahymena pyriformis (Ehrenberg) (ref. ID; 3698, 5462) or (Ehrenberg) Lwoff (ref. ID; 1219, 1335, 1618, 1629, 2100, 2245), (Ehrenberg) Lwoff, 1947 (ref. ID; 3560) reported author and year? (ref. ID; 65, 190, 191)
Syn; Glaucoma pyriformis (Ehrenberg) Schewiakoff (ref. ID; 1219); Tetrahymena geleii Furgason (ref. ID; 1618)
Description; Body ovoid and uniformly ciliated; mouth roughly triangular, longitudinal axis of the buccal cavity parallel to that of the cell itself; buccal cavity containing an undulating membrane on the right side and an adoral zone of 3 membranelles on the left; the spherical macronucleus is situated medially and is usually accompanied by 1 micronucleus; 1 contractile vacuole near the posterior end. (ref. ID; 1219)
Seventeen to twenty-three ciliary meridians; pyriform cytostome about one-tenth the body length; with or without micronucleus; bacteria-feeder; in fresh water. (ref. ID; 1618)
Measurements; Length 25-90 um. (ref. ID; 1219)
40-60 um long. (ref. ID; 1618)
Tetrahymena rostrata (Kahl) (ref. ID; 1618, 3789) reported author and year? (ref. ID; 65)
Description; In fresh water (often in dead rotifers); Kozloff (1957) found this species in the renal organ of the garden slug, Deroceras reticulatum and established axenic cultures. (ref. ID; 1618)
Histophagous ciliate. (ref. ID; 3789)
Measurements; 60-80 um long. (ref. ID; 1618)
Tetrahymena stegomyiae (Keilin) (ref. ID; 3789)
Description; See Tetrahymena rostrata-complex. (ref. ID; 3789)
Tetrahymena vorax Kidder, 1941 (ref. ID; 4123, 4210, 4217), (Kidder et al., 1940) Kidder, 1941 (ref. ID; 388) or (Kidder, Lilly & Claff) (ref. ID; 1618) reported author and year? (ref. ID; 65, 191)
Syn; Glaucoma vorax Kidder, Lilly & Claff (ref. ID; 1618)
Description; Microstomal and macrostomal cell types of the polymorphic ciliated protozoon Tetrahymena vorax utilize different food sources and thus display differences in size and shape of the food-gathering structures. The particulate-feeding microstomal form, the cell type normally present during vegetative growth in axenic culture, possesses a small oral apparatus with average dimensions of 10.6 x 5.7 um. The structure of the microstomal oral apparatus is similar to that of members of the T. pyriformis complex and like T. pyriformis. In contrast, the potentially carnivorous macrostomal cell type has a larger oral apparatus with average dimensions of 29 x 23 um, capable of engulfing prey ciliates, and a large prey receptacle, the cytopharyngeal pouch, which develops as a part of the cellular phenotype. Under normal feeding conditions, the cytopharyngeal pouch separates from the oral region only after a prey protozoon has been ingested. (ref. ID; 388)
[Macrostomal Form] The buccal cavity of the Tetrahymena vorax macrostomal cell type is located on the anterior ventral surface with the length of the cavity representing about one-fourth to one-third of the length of the cell. The anterior, right, and posterior margins of the buccal overture are curved, but the left margin is relatively straight. The buccal overture usually dips at the junction of the posterior and left margins; in certain orientations this dip appears to result from the projection of the buccal overture outward, creating a lip. The buccal overture slopes ventrally from the anterior to the posterior margin so that the extreme anterior end of the cell does not overhang all of the posterior part of the cavity. The oral apparatus may be divided into three parts, that anterior portion between the anterior ventral margin and the anterior edge of the cytostome, the large cytostomal opening, and the posterior surface. Near the anterior ventral margin, the cavity is shallow with the wall slightly rounded. The surface of the cavity slopes dorsally from the anterior ventral margin and then turns toward the anterior margin of the cytostome. This turn is rounded with the exception of the region below membranelle 3 (M3) near the right side of the cavity, where the turn is sharp. The depth at the turn in the central part of the cavity, measured from a line between the anterior and posterior margins of the buccal overture, is approximately 10-11 um. However, both the size and depth of the oral cavity vary among cells within a macrostomal population. The undulating membrane, oral ribs, and membranelle 1 (M1) originate near the anterior ventral margin of the oral apparatus. Membranelle 2 (M2) and membranelle 3 (M3) begin a short distance below M1. The kinetosomes of the three membranelles that are located in the cytoplasm of the sloping anterior surface are oriented so that the cilia project toward the posterior end of the cavity. Membranelle 1 is adjacent to the straight left wall, in a trough formed by the left wall and the left side of a plateau on which M2 is located. The surface of the plateau for M2 projects into the cavity so that this membranelle is oriented toward the right side of the cavity. The position of M1 and M2 in longitudinal sections in the sagittal plane and in transverse sections and the decreasing height of the left side of the plateau for M2 from the anterior to posterior end indicate that M1 and M2 also are situated at an angle to each other along their length. The anterior wall is straight between M2 and M3, which is located in a trough near the right side of the cavity. The right wall, lined by the oral ribs, is slightly concave near the anterior margin of the oral cavity but curves outward into the cavity along the length of M3. The cytostome or aperture in the surface that comprises the entrance into the cytopharyngeal pouch occupies most of the remainder of the oral apparatus. This opening is relatively circular and measures approximately 15-16 um in diameter. In transverse sections through the center of the cytostome and in longitudinal sections through the frontal plane, the opening encompasses most of the width of the cavity between the right and left walls. The posterior wall of the buccal cavity consists of a small curved region between the posterior margin of the cytostome and the posterior end of the buccal overture. (ref. ID; 388)
Form and size vary; bacteria-feeders elongate pyriform, 50-75 um long; saprozoic forms fusiform, 30-70 um long, decreasing in size with the age of culture; sterile particle-feeders, 60-80 um long; carnivorous and cannibals broadly pyriform, 100-250 um long; nineteen to twenty-one ciliary meridians; macronucleus ovoid, central; in carnivorous, outline irregular; apparently without micronucleus; pond water. Polymorphism. (ref. ID; 1618)
The polymorphic ciliate Tetrahymena vorax Kidder, 1941 is representative of ciliate species that offer a unique opportunity to investigate two different forms of phagocytosis in cells with the same genotype. The microstomal cell type is a particle-feeder and forms small vacuoles sequentially; the carnivorous macrostomal form, which possesses a large cytopharyngeal pouch as part of the cellular phenotype, forms a single large vacuole upon ingestion of a prey protozoon. Transformation from the microstomal to the macrostomal cell type may be induced by several methods, including subjecting cells in a medium with low nutrient concentrations to a series of heat shock followed by washing cells into non-nutrient medium. Transformation involves the resorption of the microstomal oral apparatus and the formation of the larger oral apparatus of the macrostomal cell type. Resorption and replacement being several hours before the appearance of the cytopharyngel pouch, which develops during the last 30 min and which complete the transformation. Food vacuole cannot occur between oral resorption and development of the pouch. (ref. ID; 4217)