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Tetranguladinium
From Williams et al., 2017:
[Tetranguladinium, Yu Jing-xian et al., 1983, p. 68, (ex Chen Yow-yuh et al., 1988)
Genus representing zygospores of cyanobacteria. Earlier authors considered this genus to represent acritarchs (Chen et al., 1988, p.33; Fensome et al., 1990, p.477) and dinoflagellate cysts (Batten and Lister, 1988, p.358–359). Chen et al. (1988, p.34) and the authors of pre-2004 versions of this Index were incorrect in considering that Yu Jingxian et al. (1983) did not designate a holotype for the type of the genus: hence the genus and its type were validly published when proposed.
Type species: Tetranguladinium conspicuum, Yu Jing-xian et al., 1983 (pl.30, fig.2)]; ex Chen Yow-yuh et al., 1988
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Original description: [Yu Jing-xian, 1983]: (Translation: Chen et al., 1988, p. 33):
Diagnosis:
Endocyst subspherical to ellipsoidal, enclosed by a periphragm which forms four prominences. Prominences vary in length, membranous tubular in shape, often with folds parallel to their length.
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Chen et al., 1988, p. 33:
According to Yu Jingxian et al., 1983, Tetranguladinium lacks tabulation and no archeopyle has been observed. They stated, however, that on some specimens a rupture indicates a paracingulum, but the illustrations fail to reveal either a rupture or other features indicative of a paracingulum. In the absence of paratabulation and an archeopyle, we regard this genus as an acritarch. Tetranguladinium is probably related to Sicyoidium He Cheng-quan 1980, which has a single tubular protrusion, but lacks an inner body.
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GSC: (Provisional translation GSC: courtesy R. Fensome):
Endosome subspherical to elliptical; external surface enveloped in external membrane having four prominences frequently of unequal length, assuming form of membranous tubes, frequently having many folds parallel to direction of elongation.
Discussion:
New genus universally has endosome and one thin external membrane; distinct crevice-like transverse groove visible on some specimens; should belong to Dinoflagellata, but no thecal plates or archaeopyle are seen. The present genus is distinguished from the various other genera by the fact that it has a circular or elliptical endosome and two pairs of tubular prominences unequal in length.
[Tetranguladinium, Yu Jing-xian et al., 1983, p. 68, (ex Chen Yow-yuh et al., 1988)
Genus representing zygospores of cyanobacteria. Earlier authors considered this genus to represent acritarchs (Chen et al., 1988, p.33; Fensome et al., 1990, p.477) and dinoflagellate cysts (Batten and Lister, 1988, p.358–359). Chen et al. (1988, p.34) and the authors of pre-2004 versions of this Index were incorrect in considering that Yu Jingxian et al. (1983) did not designate a holotype for the type of the genus: hence the genus and its type were validly published when proposed.
Type species: Tetranguladinium conspicuum, Yu Jing-xian et al., 1983 (pl.30, fig.2)]; ex Chen Yow-yuh et al., 1988
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Yu Jing-xian, 1983]: (Translation: Chen et al., 1988, p. 33):
Diagnosis:
Endocyst subspherical to ellipsoidal, enclosed by a periphragm which forms four prominences. Prominences vary in length, membranous tubular in shape, often with folds parallel to their length.
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Chen et al., 1988, p. 33:
According to Yu Jingxian et al., 1983, Tetranguladinium lacks tabulation and no archeopyle has been observed. They stated, however, that on some specimens a rupture indicates a paracingulum, but the illustrations fail to reveal either a rupture or other features indicative of a paracingulum. In the absence of paratabulation and an archeopyle, we regard this genus as an acritarch. Tetranguladinium is probably related to Sicyoidium He Cheng-quan 1980, which has a single tubular protrusion, but lacks an inner body.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
GSC: (Provisional translation GSC: courtesy R. Fensome):
Endosome subspherical to elliptical; external surface enveloped in external membrane having four prominences frequently of unequal length, assuming form of membranous tubes, frequently having many folds parallel to direction of elongation.
Discussion:
New genus universally has endosome and one thin external membrane; distinct crevice-like transverse groove visible on some specimens; should belong to Dinoflagellata, but no thecal plates or archaeopyle are seen. The present genus is distinguished from the various other genera by the fact that it has a circular or elliptical endosome and two pairs of tubular prominences unequal in length.