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Stichodinium
From Fensome et al., 2019:
[Stichodinium, Williams et al., 2015, p.314.
Emendation: Iakovleva, 2016, p.321 (p.11 on PDF initially published online).
Type: He Chengquan and Wang Kede, 1990, pl.2, fig.3; text-fig.2, as Wilsonidium subtile.]
Stratigraphic occurrence: Early Eocene (Ypresian), Williams et al.,2015
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Original description: [Williams et al.,2015]:
Diagnosis:
Wetzelielloidean cysts with a latiepeliform archeopyle and sutural or penitabular ornamentation that consists of features of low relief or processes that are distally free.
Description:
Shape: Dorso-ventral outline of pericyst rhomboidal,with reduced horns. Dorso-ventral outline of endocyst rounded.
Wall structure: Periphragm, bearing granules, verrucae, spines or free-standing processes that are distallybifid, trabeculate, or connected by a membranous endophragm. Ornamentation. Endophragm granular to rugose. Periphragm and endophragm moderately thick.
Pericoels: Cysts cornucavate to circumcavate.
Tabulation: Denoted by sutural or possibly penitabular granules, verrucae, spines or processes and the archeopyle.
Archeopyle: Latiepeliform. Periarcheopyle length/breadth ratio about 0.8, operculum free but may stay in place. Endoarcheopyle smaller than periarcheopyle, operculum free but may stay in place.
Furrows: Cingulum delineated by processes and by cingular horns.
Size: Intermediate.
Affinities/Discussion:
Other genera with latiepeliform archeopyles are Dracodinium, Kledodinium, Petalodinium and Piladinium. Dracodinium differs in having non-tabular processes, although some may show alignment. Kledodinium has trabeculate processes,Petalodinium does not have processes, and Piladiniumhas a membranous ectophragm. Wetzelielloidean genera with similar ornamentation are Castellodinium, Dolichodinium, Vallodinium and Wilsonidium. In Castellodinium and Dolichodinium, the perioperculum is adnate anteriorly. Vallodinium has an equiepeliform archeopyle and Wilsonidium has a hyperepeliform archeopyle. The holotype of Stichodinium subtile has a pericyst length and width (excluding processes) both of 94 µm and the endocyst is 74 µm across.
[Stichodinium, Williams et al., 2015, p.314.
Emendation: Iakovleva, 2016, p.321 (p.11 on PDF initially published online).
Type: He Chengquan and Wang Kede, 1990, pl.2, fig.3; text-fig.2, as Wilsonidium subtile.]
Stratigraphic occurrence: Early Eocene (Ypresian), Williams et al.,2015
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Williams et al.,2015]:
Diagnosis:
Wetzelielloidean cysts with a latiepeliform archeopyle and sutural or penitabular ornamentation that consists of features of low relief or processes that are distally free.
Description:
Shape: Dorso-ventral outline of pericyst rhomboidal,with reduced horns. Dorso-ventral outline of endocyst rounded.
Wall structure: Periphragm, bearing granules, verrucae, spines or free-standing processes that are distallybifid, trabeculate, or connected by a membranous endophragm. Ornamentation. Endophragm granular to rugose. Periphragm and endophragm moderately thick.
Pericoels: Cysts cornucavate to circumcavate.
Tabulation: Denoted by sutural or possibly penitabular granules, verrucae, spines or processes and the archeopyle.
Archeopyle: Latiepeliform. Periarcheopyle length/breadth ratio about 0.8, operculum free but may stay in place. Endoarcheopyle smaller than periarcheopyle, operculum free but may stay in place.
Furrows: Cingulum delineated by processes and by cingular horns.
Size: Intermediate.
Affinities/Discussion:
Other genera with latiepeliform archeopyles are Dracodinium, Kledodinium, Petalodinium and Piladinium. Dracodinium differs in having non-tabular processes, although some may show alignment. Kledodinium has trabeculate processes,Petalodinium does not have processes, and Piladiniumhas a membranous ectophragm. Wetzelielloidean genera with similar ornamentation are Castellodinium, Dolichodinium, Vallodinium and Wilsonidium. In Castellodinium and Dolichodinium, the perioperculum is adnate anteriorly. Vallodinium has an equiepeliform archeopyle and Wilsonidium has a hyperepeliform archeopyle. The holotype of Stichodinium subtile has a pericyst length and width (excluding processes) both of 94 µm and the endocyst is 74 µm across.