Back
Vallodinium
From Fensome et al., 2019:
Williams et al., 2015, p.315–316.
Type: Jan du Chêne and Adediran, 1985, pl.9, figs.1–2, as Wilsonidium nigeriaense.
---------------------------------------------------------------------------------------------------
Original description: [Williams et al., 2009]:
Diagnosis:
Wetzelielloidean cysts with an equiepeliform archeopyle, pericyst ornament that is conspicuously sutural to penitabular and processes that are distally united by trabeculae or by ectophragm.
Description.:
Shape: Dorsoventral outline of pericyst rhomboidal, with well-developed horns; right antapical horn often reduced but may be same length as left antapical horn. Dorsoventral outline of endocyst rhomboidal to pentagonal.
Wall structure: Periphragm thin, ornamented with sutural to penitabular processes that are distally united by trabeculae and membranous ectophragm. Endophragm thin, smooth to scabrate.
Pericoels: Cornucavate to narrowly circumcavate.
Tabulation: Precisely delineated by sutural or penitabular processes; few if any intratabular processes.
Archeopyle: Equiepeliform. Periarcheopyle with detached operculum. Endoarcheopyle usually same size or slightly smaller than periarcheopyle.
Furrows: Cingulum delineated by single row of penitabular processes. Sulcus outlined by penitabular or sutural processes; posterior sulcal plate clearly delineated.
Size: Intermediate to large.
Dimensions:
Holotype of Vallodinium nigeriaense: pericyst length 110 µm, pericyst width 104 µm and endocyst dimensions 70 by 72 µm.
The holotype of Vallodinium echinosuturatum has a pericyst 149 µm long and 143 µm wide and an endocyst 99 µm long and 91 µm wide.
Affinities/Discussion:
Other genera with an equiepeliform archeopyle are Apectodinium, Axiodinium, Charlesdowniea, Epelidinium and Sophismatia. Apectodinium and Axiodinium have processes that are distally free, Charlesdowniea has an ectophragm, Epelidinium has a pericyst that is smooth or ornamented only with features of low relief and Sophismatia has trabeculate processes. Castellodinium, Dolichodinium, Stichodinium and Wilsonidium also have conspicuously penitabular to pandasutural ornamentation; however, they differ in archeopyle type. Castellodinium has a soleiform archeopyle, Dolichodinium has a hypersoleiform archeopyle, Stichodinium has a latiepeliform archeopyle and Wilsonidium has a hyperepeliform archeopyle.
Williams et al., 2015, p.315–316.
Type: Jan du Chêne and Adediran, 1985, pl.9, figs.1–2, as Wilsonidium nigeriaense.
---------------------------------------------------------------------------------------------------
Original description: [Williams et al., 2009]:
Diagnosis:
Wetzelielloidean cysts with an equiepeliform archeopyle, pericyst ornament that is conspicuously sutural to penitabular and processes that are distally united by trabeculae or by ectophragm.
Description.:
Shape: Dorsoventral outline of pericyst rhomboidal, with well-developed horns; right antapical horn often reduced but may be same length as left antapical horn. Dorsoventral outline of endocyst rhomboidal to pentagonal.
Wall structure: Periphragm thin, ornamented with sutural to penitabular processes that are distally united by trabeculae and membranous ectophragm. Endophragm thin, smooth to scabrate.
Pericoels: Cornucavate to narrowly circumcavate.
Tabulation: Precisely delineated by sutural or penitabular processes; few if any intratabular processes.
Archeopyle: Equiepeliform. Periarcheopyle with detached operculum. Endoarcheopyle usually same size or slightly smaller than periarcheopyle.
Furrows: Cingulum delineated by single row of penitabular processes. Sulcus outlined by penitabular or sutural processes; posterior sulcal plate clearly delineated.
Size: Intermediate to large.
Dimensions:
Holotype of Vallodinium nigeriaense: pericyst length 110 µm, pericyst width 104 µm and endocyst dimensions 70 by 72 µm.
The holotype of Vallodinium echinosuturatum has a pericyst 149 µm long and 143 µm wide and an endocyst 99 µm long and 91 µm wide.
Affinities/Discussion:
Other genera with an equiepeliform archeopyle are Apectodinium, Axiodinium, Charlesdowniea, Epelidinium and Sophismatia. Apectodinium and Axiodinium have processes that are distally free, Charlesdowniea has an ectophragm, Epelidinium has a pericyst that is smooth or ornamented only with features of low relief and Sophismatia has trabeculate processes. Castellodinium, Dolichodinium, Stichodinium and Wilsonidium also have conspicuously penitabular to pandasutural ornamentation; however, they differ in archeopyle type. Castellodinium has a soleiform archeopyle, Dolichodinium has a hypersoleiform archeopyle, Stichodinium has a latiepeliform archeopyle and Wilsonidium has a hyperepeliform archeopyle.