Genus Trinema Dujardin, 1841, emend. Łuców et al., 2024

Diagnosis: Shell with two types of body scales: (1) large, round or broadly elliptical scales and (2) smaller, round to elliptical scales. The small scales cover the area around the aperture and are located underneath the boundaries of the large scales or in the interstices of those scales. Pseudostome subterminal, invaginated and positioned ventrally, round or elliptical, bordered by one or more rows of small denticulate apertural scales. Vesicular or granulated nucleus.

Habitat: very common in water, between mosses and in soil.

Remarks: Species are hard to identify.

Overview of genus Trinema

T. acinus Dujardin, 1841 = T. enchelys Ehrenberg, 1838
T. alofsi Stepanek, 1963
T. caudatum Playfair, 1917 = Playfairina
T. chardezi Decloitre, 1981
T. chavannesi Decloitre, 1970
T. ciliata Stepanek, 1963
T. clipelina Rauenbusch, 1987
T. complanatum Penard, 1890
— var. aerophila Decloitre, 1950
— var. aerophila Bonnet & Thomas, 1960
— var. aerophila f. punctata Decloitre, 1961
— var. aerophila f. gigantea Decloitre, 1980
— var. constricta Hoogenraad and De Groot,1951 (Corythion?)
— var. elongata Decloitre, 1973
— var. gigantea Decloitre, 1980
— var. gigantea f. punctata Decloitre, 1980
— var. globulosa f. minima, Chardez, 1976
— var. globulosa Chardez, 1959
— var. inaequalis Decloitre, 1969
— var. inflata Decloitre, 1970
— var. platystoma Chardez, 1972
— var. platystoma Schönborn, 1964
—– f. atama Sudzuki, 1965
T. constricta Certes, 1889 = Corythion constricta Cash, Wales and Hopkinson, 1915
T. contraria Decloitre , 1961
T. cornuta Decloitre, 1961
T. elongata Godeanu nomen nudum
T. diatomacea Van Oye 1926
—  var. corona Van Oye, 1926
T. enchelys (Ehrenberg, 1838) Leidy, 1878
— var. aerophila Decloitre, 1950 = T. complanatum var. aerophila Decloitre, 1950
— var. bryophilvar. aerophilaa Penard (only reference in Heinis, 1911)
— var. bonneti Decloitre, 1970
— var. caeolata Stepanek, 1967
— var. daruma Sudzuki
— var. galeata Penard, 1890 = T. galeata (Penard) Jung, 1942
— var. grandis Chardez, 1960 = T. grandis (Chardez, 1960) Golemansky, 1963
— var. nasturticola Decloitre, 1962
— var. plenum Kufferath, 1932
—– f. biconvexa Awerinzew, 1907
—– f. multidentata Decloitre, 1958
—– f. multidentata Haager, 1969
—– f. ampulla Jung and Spatz, 1938
T. galeata (Penard) Jung 1942
T. intermedia Decloitre, 1965
T. leidyi Chardez, ? Decloitre, 1981
T. lineare Penard, 1890
— var. gigantea Guru and Dash, 1983
— var. globulosa Stepanek, 1967
— var. grandis Decloitre, 1971
— var. pellucida Stepanek, 1967
— var. pliocenica Boeuf and Gilbert, 1997
— var. terricola Decloitre, 1962
— var. rectangularis Decloitre, 1970
—– f. minuscula Chardez, 1971
—– f. major Sudzuki, 1965
—– f. truncatum Chardez, 1964
T. lineastoma Decloitre 1962
T. nassa Decloitre, 1965
T. navicularis Decloitre, 1973
T. penardi Thomas & Chardez, 1958
T. pleurostoma Carter, 1857
T. verrucosa Francé, 1897
T. staryi Balik, 1995
T. sauvineti Certes 1889 = ciliate
T. taraneki Stepanek, 1968
T. quadratum Van Oye, 1948
T. spinosum Penard 1890 = Lecythium var. pellucida Stepanek, 1967
— var. pliocenica Boeuf and Gilbert, 1997
— var. terricola Decloitre, 1962
— var. rectangularis Decloitre, 1970
—– f. minuscula Chardez, 1971
—– f. major Sudzuki, 1965
—– f. truncatum Chardez, 1964
T. lineastoma Decloitre 1962
T. nassa Decloitre, 1965
T. navicularis Decloitre, 1973
T. penardi Thomas & Chardez, 1958
T. pleurostoma Carter, 1857
T. verrucosa Francé, 1897
T. staryi Balik, 1995
T. sauvineti Certes 1889 = ciliate
T. taraneki Stepanek, 1968
T. quadratum Van Oye, 1948
T. spinosum Penard 1890 = Lecythium