Paramecium O. F. Muller, 1773 , , ,
Synonym; Paramaecium O. F. Muller (ref. ID; 1618)

[ref. ID; 2014]
Medium- to large sized ciliate (120-300 um long), ovoid, elongate, foot- or cigar-shaped. The anterior end may be rounded or obliquely truncated and the posterior rounded or conical. The shape is rather asymmetrical due to the presence of an oblique depression, the oral groove, running from the apex of the cell to about the middle of the body on the ventral surface. The oral aperture is located at the posterior end of the oral groove. While the oral groove is prominent and easily seen the aperture is rarely visible without staining the cell with silver. Inside the buccal cavity there is a comparatively small undulating membrane on the right and 2 membranelles called peniculi lying alongside each other. Membranelle M3 comprise four rows of kinetosomes which diverge centrally to form a structure known as a quadrulus. Somatic ciliation is complete and uniform with 1, 2 or 3 hexagonal units. There are both pre- and post-oral sutures and trichocysts present. 1 to many (commonly 2) contractile vacuoles present which may be served by radiating canals. Cytoproct on the ventral surface located sub-orally. Macronucleus ovoid to reniform in shape, usually centrally located with variable number of micronuclei close by. Locomotion characteristically vigorous and spiralling anticlockwise. Wenrich (1928). The species of Paramecium are still in a state of flux. The classical species P. aurelia has recently been subdivided into 14 sibling species by Sonneborn (1975) and Gates, Powelson and Berger (1974) and Gates and Berger (1976) have discussed the morphological separation of these species. Vivier (1974) also reviews the classically named 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)

Paramecium aurelia Ehrenberg, 1838 (ref. ID; 1335, 1622, 1629, 2245) or 1848 (ref. ID; 3116) reported year? (ref. ID; 1618)
Syn; Paramecium aurelia Dujardin, 1841
Description; Two small vesicular micronuclei, a massive macronucleus; two contractile vacuoles on aboral surface; posterior end more rounded that P. caudatum; in fresh water. (ref. ID; 1618)
Measurements; 120-180 um long. (ref. ID; 1618)
Paramecium bursaria Ehrenberg (ref. ID; 1219, 1618) or (Ehrenberg, 1831) Focke, 1836 (ref. ID; 4611), (Ehrenberg) Focker, 1836 (ref. ID; 1335, 1622, 1629, 2245), (Ehrenberg) Focker, 1843 (ref. ID; 3116) reported author and year? (ref. ID; 3292)
Syn; Loxodes bursaria Ehrenberg, 1831 (ref. ID; 4611)
Description; Foot-shaped, more or less flattened; uniform ciliation except for a group of long caudal cilia; green with symbiotic zoochlorellae; a long broad vestibulum leads to the buccal cavity, the buccal ciliary apparatus is characterized by 2 "peniculi"; 1 compact micronucleus; 2 contractile vacuoles; numerous prominent trichocysts. (ref. ID; 1219)
Foot-shaped, somewhat compressed; green with zoochlorellae as symbionts; a compact micronucleus; a macronucleus; two contractile vacuoles; in fresh water. (ref. ID; 1618)
Measurements; Length 180-300 um. (ref. ID; 1219)
About 100-150 by 50-60 um. (ref. ID; 1618)
Paramecium calkinsi Woodruff, 1921 (ref. ID; 1335, 1622, 4611) reported year? (ref. ID; 1618)
Description; Foot-shaped; posterior end broadly rounded; two vesicular micronuclei; two contractile vacuoles; in fresh, brackish and salt water. (ref. ID; 1618)
Measurements; 100-150 by 50 um. (ref. ID; 1618)
Paramecium caudatum Ehrenberg, 1833 (ref. ID; 4488, 4611) or 1838 (ref. ID; 1219, 1622, 1629, 2245, 3116) reported year? (ref. ID; 1618, 3342, 3698, 5462) reported author and year? (ref. ID; 3292, 4064)
Syn; Paramecium aurelia O. F. Muller, 1786 (ref. ID; 1622)
Description; Cigar-shaped, posterior end bluntly pointed and with a group of long cilia, ciliation otherwise uniform; vestibulum long and slightly oblique; buccal cavity with one endoral membrane and 2 peniculi; 1 ellipsoid macronucleus and 1 compact micronucleus; 2 contractile vacuoles, each with radial canals, near the aboral surface, numerous trichocysts, which may discharge explosively, all over the body. (ref. ID; 1219)
With a compact micronucleus, a massive macronucleus; two contractile vacuoles on aboral surface; posterior end bluntly pointed; in fresh water. The most widely distributed species. (ref. ID; 1618)
Measurements; Length 90-150 um. (ref. ID; 1219)
180-300 um long. (ref. ID; 1618)
180-260 x 40-50 um. (ref. ID; 3342)
Paramecium jenningsi Diller & Earl, 1958 (ref. ID; 1618) reported author and year? (ref. ID; 3813, 4064)
Description; Resembles P. aurelia in general morphology; two micronuclei larger than those of P. aurelia; macronuclear anlagen with long persisting chromatinic centers. (ref. ID; 1618)
Measurements; 115-218 um long. (ref. ID; 1618)
Paramecium multimicronucleatum Powers & Mitchell, 1910 (ref. ID; 1335, 1622) reported year? (ref. ID; 1618) reported author and year? (ref. ID; 3292, 3990)
Description; 3-7 contractile vacuoles; four or more vesicular micronuclei; a single macronucleus; in fresh water. (ref. ID; 1618)
The somatic kinetosomes, single or double, appear as small dark granules; issuing from them is a kinetodesmal (Kd) fiber that runs anteriorly and to the right of the kinety, overlapping with more anteriorly located fibers to form a single kinetosomes are more closely spaced and the kinetodesmata are thicker by virtue of being formed by a larger number of overlapping Kd fibers. (ref. ID; 3990)
Measurements; The largest species, 200-330 um long. (ref. ID; 1618)
Paramecium polycaryum Woodruff, 1923 (ref. ID; 1335, 1622) reported year? (ref. ID; 1618)
Description; Form similar to P. bursaria; two contractile vacuoles; 3-8 vesicular micronuclei; in fresh water. (ref. ID; 1618)
Measurements; 70-110 um long. (ref. ID; 1618)
Paramecium putrinum Claparede & Lachmann, 1858 (ref. ID; 1622, 1629) 1859 (ref. ID; 4611) reported year? (ref. ID; 1219, 1618)
Description; Similar to P. bursaria but without zoochlorellae; macronucleus elongated, kidney-shaped; 1 micronucleus; only 1 contractile vacuole; no trichocysts (Lepsi, 1926; Kahl, 1930) Records of P. putrinum are scanty, and it is in fact doubtful whether the species is valid. This problem is of some saprobiological interest since Liebmann (1962) classified P. putrinum as a polysaprobic indicator organism. On the other hand, Sramek-Husek (1954) failed to find any specimens of P. putrinum during his saprobiological studies in Czehoslovakia; all representatives of the genus Paramecium that he found in the more heavily polluted zones were referable to P. trichium. Therefore, Sramek-Husek submitted that the polysaprobic "P. putrinum" of earlier authors is really P. trichium Stokes. P. putrinum sensu Liebmann has 2 contractile vacuoles, both shown with radial canals; P. putrinum sensu Liebmann was recorded from the sludge of polluted reservoirs, dammed rivers, lakes etc., in the upper zone of trickling filters, sewage drains, and in floating tufts of Sphaerotilus. Taxonomic studies of "P. putrinum" and P. trichium are thus urgently required. (ref. ID; 1219)
Similar to P. bursaria, but a single contractile vacuole and an elongated macronucleus; no zoochlorellae; in fresh water. (ref. ID; 1618)
Measurements; About 130 um long (ref. ID; 1219)
80-150 um long. (ref. ID; 1618)
Paramecium sonneborni Aufderheide, Daggett & Nerad, 1983 (ref. ID; 4061 original paper)
See; Paramecium aurelia complex
Description; [Body morphology] The shape of the cell body from a cloned population of organisms grown at maximum rate at 27 degrees C is typical for that of the P. aurelia complex with the exception that the posterior end of most cells is pointed, bearing a superficial resemblance to Paramecium caudatum. Two contractile vacuole are present. (ref. ID; 4061)
[Nuclear morphology] One macronucleus is present, ca. 70 um long, showing the prolate spheroid shape characteristic of all species of Paramecium. In interphase cells, the macronucleus is ventral and anterior to the oral apparatus, as is also usual with paramecia. Two vesicular micronuclei are consistently present. Many micronuclei show a concentric arrangement of the chromatin, while others have chromatin dispersed in a coarse reticulum. Twenty micronuclei examined in 12 living cells, using phase-contrast optics, have a mean diameter of 4.9 um (+/- 0.18 SE), with a range of 3.5-6.7 um. (ref. ID; 4061)
[Sexual behavior] Both conjugation and autogamy have been observed, and two macronuclear anlagen are seen after fertilization. Two mating types have been identified. Mating-type determination appears to be karyonidal, although cytoplasmic determination has not been completely ruled out. Mating-reactive cells of this organism will not react with mating-reactive cells of any of the other 14 species assignable to the aurelia complex. These is no apparent diurnal cycle. (ref. ID; 4061)
[Further remarks] The life expectancy of clones of our new species is relatively long compared to other species in the aurelia complex. Clones are viable for at least 250 generations. No endosymbionts have been detected in the species. (ref. ID; 4061)
Etymology; The new species has been named Paramecium sonneborni n. sp. in honor of the late Dr. Tracy M. Sonneborn of Indiana University. (ref. ID; 4061)
Type locality; College Station, Texas (Lat. 30 degrees37'55''N, Long. 96 degrees18'15''W). (ref. ID; 4061)
Type-specimens; Holotype and paratype slides (Nos. USNM31926 and 31927) have been deposited in the Ciliate Type Slide Collection, Smithsonian Institution, Washington, D.C. Paratype specimens remain in the collection of the senior author. (ref. ID; 4061)
Type culture; Paramecium sonneborni stock TAMU:0580:1 ATCC 30995) (ref. ID; 4061)
Measurements; Maximum body length of 26 fixed, silver-impregnated specimens ranged from 130 to 186 um, with a mean length of 154.4 um (2.9 +/- SE). Maximum body width of the 26 cells ranged from 39 to 64 um, with a mean width of 50.3 um (+/- 1.3 SE). (ref. ID; 4061)
Paramecium trichium Stokes, 1885 (ref. ID; 1335, 1622, 2245) reported year? (ref. ID; 1219, 1618, 3342, 3698) reported author and year? (ref. ID; 646)
Description; Body shape highly variable, more or less ellipsoid, somewhat flattened; ciliation uniform except for a group of long caudal cilia; vestibulum and buccal equipment similar to those of P. bursaria; 1 macronucleus; 1 compact micronucleus; 2 contractile vacuole, each with a convoluted outlet; unlike other members of its genus, P. trichium has a contractile vacuole without radial canals but with tributary vacuoles; numerous trichocysts all over the body; posterior part of the body more or less filled with dark granules. According to Sramek-Husek (1954), P. pseudoputrinum Baumeister is referable to P. trichium. (ref. ID; 1219)
Oblong, somewhat compressed; a compact micronucleus; two contractile vacuoles deeply situated, each with a convoluted outlet; in fresh water. (ref. ID; 1618)
Measurements; Length 50-120 um. (ref. ID; 1219)
50-105 (80-90) um long. (ref. ID; 1618)
80-110 x 45-60 um. (ref. ID; 3342)
Paramecium woodruffi Wenrich, 1928 (ref. ID; 1335, 1618, 1622, 4611)
Description; Similar to P. polycaryum; two contractile vacuoles; 3-4 vesicular micronuclei; brackish water. (ref. ID; 1618)
Measurements; 150-210 um long. (ref. ID; 1618)