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Membranilarnacia
From Williams et al., 2017:
[Membranilarnacia, Eisenack, 1963a, p. 99, 318; Emendation: Williams and Downie, 1966c, p. 219.
Tax. sen. syn.: Membranilarnax, by implication in Downie and Sarjeant (1965, p.130) who questionably transferred the "type species" of Membranilarnax, Membranilarnax pterospermoides, to Membranilarnacia — however, Lentin and Williams (1973, p.92) retained Membranilarnacia.
Type species: originally as Membranilarnax leptoderma, Cookson and Eisenack, 1958 (pl.10, fig.9)] ; Membranilarnacia leptoderma, Eisenack, 1963
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Original description: [Eisenack, 1963]:
Diagnosis:
Central shell spherical, oval or ellipsoidal, generally thick-walled, surrounded by a second, approximately concentric, usually thin-walled envelope, which is supported by props or pillars arising almost perpendicularly from the central shell. These props (supports) may be branched, expanded, or ramified in complicated fashion at their extremity but are rod-shaped or cylindrical at their lower ends. Pylome polar or subpolar in location on oval shells.
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Modified description:
Stover and Evitt 1978, p. 63-64:
Synopsis:
Cysts cavate; endocyst subspherical, surrounded by a thinner, commonly folded pericyst; endophragm and periphragm connected by slender rods, pillars, or processes, apparently more common on the hypocyst and evidently not paraplate related; archeopyle apical, type uncertain, probably Type tA.
Description:
Shape: Endocyst subspherical; shape of pericyst varies owing folding.
Wall relationships: Cavate, thin periphragm concentric and relatively close to thicker endophragm.
Wall features: No parasutural features. Endophragm granulate to rugulate; periphragm smooth to faintly ornamented; pericoel with a few to several slender rods or pillars, which are evidently not related to paraplates and apparently are more numerous on the hypocyst than on the epicyst. Paratabulation: None clearly indicated.
Archeopyle: Apical, type uncertain, probably Type tA; operculum unknown. Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate.
Affinities:
Membranilarnacia differs from Eatonicysta in having fewer processes that are evidently not paraplate-related.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Membranilarnacia Eisenack, 1963a, emend. Williams and Downie, 1966c. Synopsis from Stover and Evitt (1978), cysts cavate, endocyst subspherical, surrounded by a thinner, commonly folded pericyst; endophragm and periphragm connected by slender rods, pillars, or processes, apparently more common on the hypocyst and evidently not paraplate related; archeopyle apical, type uncertain, probably type [tA].
[Membranilarnacia, Eisenack, 1963a, p. 99, 318; Emendation: Williams and Downie, 1966c, p. 219.
Tax. sen. syn.: Membranilarnax, by implication in Downie and Sarjeant (1965, p.130) who questionably transferred the "type species" of Membranilarnax, Membranilarnax pterospermoides, to Membranilarnacia — however, Lentin and Williams (1973, p.92) retained Membranilarnacia.
Type species: originally as Membranilarnax leptoderma, Cookson and Eisenack, 1958 (pl.10, fig.9)] ; Membranilarnacia leptoderma, Eisenack, 1963
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eisenack, 1963]:
Diagnosis:
Central shell spherical, oval or ellipsoidal, generally thick-walled, surrounded by a second, approximately concentric, usually thin-walled envelope, which is supported by props or pillars arising almost perpendicularly from the central shell. These props (supports) may be branched, expanded, or ramified in complicated fashion at their extremity but are rod-shaped or cylindrical at their lower ends. Pylome polar or subpolar in location on oval shells.
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Modified description:
Stover and Evitt 1978, p. 63-64:
Synopsis:
Cysts cavate; endocyst subspherical, surrounded by a thinner, commonly folded pericyst; endophragm and periphragm connected by slender rods, pillars, or processes, apparently more common on the hypocyst and evidently not paraplate related; archeopyle apical, type uncertain, probably Type tA.
Description:
Shape: Endocyst subspherical; shape of pericyst varies owing folding.
Wall relationships: Cavate, thin periphragm concentric and relatively close to thicker endophragm.
Wall features: No parasutural features. Endophragm granulate to rugulate; periphragm smooth to faintly ornamented; pericoel with a few to several slender rods or pillars, which are evidently not related to paraplates and apparently are more numerous on the hypocyst than on the epicyst. Paratabulation: None clearly indicated.
Archeopyle: Apical, type uncertain, probably Type tA; operculum unknown. Paracingulum: Not indicated.
Parasulcus: Not indicated.
Size: Intermediate.
Affinities:
Membranilarnacia differs from Eatonicysta in having fewer processes that are evidently not paraplate-related.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Membranilarnacia Eisenack, 1963a, emend. Williams and Downie, 1966c. Synopsis from Stover and Evitt (1978), cysts cavate, endocyst subspherical, surrounded by a thinner, commonly folded pericyst; endophragm and periphragm connected by slender rods, pillars, or processes, apparently more common on the hypocyst and evidently not paraplate related; archeopyle apical, type uncertain, probably type [tA].