Frontonia Ehrenberg, 1833 (ref. ID; 3690) or 1838 (ref. ID; 2014)
Class Oligohymenophora: Subclass Hymenostomata: Order Hymenostomatida (ref. ID; 2014)

[ref. ID; 2014]
Outline-shape elongate to oval, more or less dorso-ventrally flattened, rounded at both poles and usually slightly wider anteriorly, body flexible. Oral aperture, located in the anterior body half in the center of the ventral surface, is pyriform in shape being narrow anteriorly, truncated posteriorly and surrounded by close-set cilia which extend posteriorly bordering a post-oral groove. There is an undulating membrane on the right of the aperture and 3 membranelles on the left running closely together along the margin of the aperture. The buccal cavity is shallow somatic ciliation uniform with both pre-oral and post-oral sutures. The post-oral suture lies along a narrow groove which appears to be an opening into the cell. When filaments of algae are consumed, this groove opens up and seems to aid ingestion. Many trichocysts present. Contractile vacuole may sometimes be served by radiating canals.
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)

Frontonia acuminata Ehrenberg, 1833 (ref. ID; 1622, 1629, 1896, 2245, 3116, 4522) reported year? (ref. ID; 1219) or (Ehrenberg, 1833) Buetschli, 1889 (ref. ID; 4488, 4611)
Syn; Ophryoglena acuminata Ehrenberg, 1833 (ref. ID; 4611)
Description; Body ovoid to ellipsoid; dorsal side slightly convex, ventral face flat; complete uniform ciliation; buccal cavity lies in anterior right third of the cell; ciliary rows of the right and left ventral surface meet in a preoral suture and a very post-oral groove, respectively; post-oral groove usually nearly close; buccal cavity lancet-like with pointed anterior and truncate posterior end, complex buccal ciliation consisting of compound ciliary organelles; single macronucleus ellipsoid in the middle of the body; 1 micronucleus; 1 contractile vacuole near the right margin. (ref. ID; 1219)
Measurements; Length 50-150 um. (ref. ID; 1219)
Frontonia acuminata f. typica Kahl, 1931 (ref. ID; 1219)
Description; Highly flattened with an accumulation of dark granules near the anterior pole. (ref. ID; 1219)
Frontonia acuminata var. angusta Kahl, 1931 (ref. ID; 1219, 1622, 4611)
See; Frontonia angusta (ref. ID; 4611)
Description; Moderately flattened, without granules. (ref. ID; 1219)
Frontonia atra Ehrenberg, 1833 (ref. ID; 1622, 1629) reported year? (ref. ID; 3342) or (Ehrenberg, 1833) Buetschli, 1889 (ref. ID; 4488, 4611) reported author and year? (ref. ID; 191)
Syn; Ophryoglena atra Ehrenberg, 1833 (ref. ID; 4611)
Measurements; 135 x 68 um. (ref. ID; 3342)
Frontonia branchiostomae Codreanu, 1928 (ref. ID; 1622) reported year? (ref. ID; 1618)
Description; Commensal in the branchial cavity of Amphioxus. (ref. ID; 1618)
Measurements; 75-100 by 55-95 um. (ref. ID; 1618)
Frontonia depressa (Stokes, 1886) (ref. ID; 3593) reported year? (ref. ID; 3698, 4842), (Stokes, 1886) Kahl, 1931 (ref. ID; 4861) or (Stokes, 1886) Penard (ref. ID; 1622) reported year? (ref. ID; 1618) reported author and year? (ref. ID; 191)
Syn; Frontonia parvula Penard, 1922 (ref. ID; 1622)
Description; Oval, flattened; oval mouth, with 3 vestibular meridians on right, an undulating membrane on left and a membranella in the middle; 40-50 meridians, with short cilia; body surface smooth, though with trichocysts; cysts show little dedifferentiation; fresh water, moss and soil. (ref. ID; 1618)
Measurements; 60-80 by 30-40 um. (ref. ID; 1618)
Frontonia leucas (Ehrenberg, 1833) Ehrenberg, 1838 (ref. ID; 4611, 4613) or Ehrenberg, 1838 (ref. ID; 1308, 1335, 1622, 1629, 2099, 2245, 3116, 4488) reported year? (ref. ID; 1618, 3690, 5462) reported author and year? (ref. ID; 191, 3292)
Syn; Bursaria leucas Ehrenberg, 1833 (ref. ID; 4611); Frontonia vermalis Ehrenberg, 1883 (ref. ID; 1622, 3116); Ophryoglena magna Maupas, 1883 (ref. ID; 1622); Ophryoglena vorax Smith, 1897 (ref. ID; 1622); Plagiopyla hatchi Stokes, 1891 (ref. ID; 1622)
Description; Feeds on filamentous algae, but may take in Arcella and even large amoebae; among algae in fresh water. (ref. ID; 1618)
Measurements; 150-600 um long. (ref. ID; 1618)
Frontonia marina Fabre-Domergue, 1891 (ref. ID; 645, 1622, 2117, 3119) reported year? (ref. ID; 3690, 3771)
Syn; Frontonia leucas var. marina Florentin, 1899 (ref. ID; 1622)
Description; This ciliate feeds on bacteria and diatoms. Fr. marina varies widely in size-according to Kahl, from 150 to 600 um. Specimens from Solar Lake ranged from 110 to 240 um in length, and from 65 to 85 um in width. The contractile vacuole lies dorsally and has one excretory pore. The cilia are 3 um long. According to Gil et al. (1964), the length of the first peniculus is species-specific. Because no data were available for Fr. marina we measured the first peniculus in 20 animals, and found it to be 27 to 30 um long. (ref. ID; 645)
Frontonia microstoma Kahl (ref. ID; 1618, 1622, 1890)
Description; In brackish water. (ref. ID; 1618)
Measurements; 200-300 um long. (ref. ID; 1618)
Frontonia vernalis Ehrenberg, 1833 (ref. ID; 4237) or 1883 (ref. ID; 1622, 3116) reported author and year? (ref. ID; 3292)
See; Frontonia leucas (ref. ID; 1622, 3116)
Description; Zoochlorellae-bearing ciliates. (ref. ID; 4237)