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Yalkalpodinium
From Williams et al., 2017:
[Yalkalpodium, Morgan, 1980, p. 34; Emendation: Riding and Helby, 2001d, p.99.
Type species: Yalkalpodinium scutum, Morgan, 1980 (pl.31, figs.17–18)]
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Original description: [Morgan, 1980]:
Description:
Cysts two-layered, subcircular to subpentagonal ambitus; endophragm and periphragm closely appressed on dorsal and ventral sides, with an ambital pericoel; small apical horn may or may not be present; cingulum and sulcus weakly marked; no other traces of tabulation; archeopyle apical, operculum free.
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Modified description:
Stover and Williams, 1987, p. 231:
Synopsis:
Cysts proximate, circumcavate; endocyst subspherical, slightly flattened dorsoventrally; pericyst outline subcircular to pentagonal with moderate cingular protrusions; two wall layers appressed dorsally and ventrally; pericoel tends to be wider antapically and cingularly than elsewhere; archeopyle apical, type [tA], with deep midventral parasulcal notch; operculum free.
Description:
Shape: Cyst slightly flattened dorsoventrally; outline of pericyst subcircular to pentagonal; a short apical bulge may be present; endocyst subspherical.
Wall relationships: Cyst circumcavate, pericoel tends to be wider antapically and cingularly than elsewhere; wall layers appressed dorsally and ventrally.
Wall features: Endophragm ornamented with features of low relief; periphragm externally smooth, ornamented internally with small scale features; periphragm may be perforate antapically.
Archeopyle: Apical, type [4A], margin zigzag with deep midventral parasulcal notch.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Poorly expressed by transverse folds of the periphragm and lateral bulges.
Parasulcus: Position inferred anteriorly by parasulcal notch and posteriorly by ill-defined area of wall separation.
Size: Large, width about 125 µm.
Affinities:
Yalkalpodinium differs from Senoniasphaera Clarke and Verdier 1967 in having a subspherical rather than a lenticular endocyst.
[Yalkalpodium, Morgan, 1980, p. 34; Emendation: Riding and Helby, 2001d, p.99.
Type species: Yalkalpodinium scutum, Morgan, 1980 (pl.31, figs.17–18)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Morgan, 1980]:
Description:
Cysts two-layered, subcircular to subpentagonal ambitus; endophragm and periphragm closely appressed on dorsal and ventral sides, with an ambital pericoel; small apical horn may or may not be present; cingulum and sulcus weakly marked; no other traces of tabulation; archeopyle apical, operculum free.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 231:
Synopsis:
Cysts proximate, circumcavate; endocyst subspherical, slightly flattened dorsoventrally; pericyst outline subcircular to pentagonal with moderate cingular protrusions; two wall layers appressed dorsally and ventrally; pericoel tends to be wider antapically and cingularly than elsewhere; archeopyle apical, type [tA], with deep midventral parasulcal notch; operculum free.
Description:
Shape: Cyst slightly flattened dorsoventrally; outline of pericyst subcircular to pentagonal; a short apical bulge may be present; endocyst subspherical.
Wall relationships: Cyst circumcavate, pericoel tends to be wider antapically and cingularly than elsewhere; wall layers appressed dorsally and ventrally.
Wall features: Endophragm ornamented with features of low relief; periphragm externally smooth, ornamented internally with small scale features; periphragm may be perforate antapically.
Archeopyle: Apical, type [4A], margin zigzag with deep midventral parasulcal notch.
Paratabulation: Indicated by archeopyle only.
Paracingulum: Poorly expressed by transverse folds of the periphragm and lateral bulges.
Parasulcus: Position inferred anteriorly by parasulcal notch and posteriorly by ill-defined area of wall separation.
Size: Large, width about 125 µm.
Affinities:
Yalkalpodinium differs from Senoniasphaera Clarke and Verdier 1967 in having a subspherical rather than a lenticular endocyst.