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Membranophoridium
From Williams et al., 2017:
[Membranophoridium, Gerlach, 1961, p. 198-199; Emendation: Stover and Evitt, 1978, p. 64-65
Tax. jun. syn. of Chiropteridium, according to Brosius (1963, p.47) and Schindler (1992, p.202) - however, Lentin and Williams (1993, p.421) retained Membranophoridium.
Type species: Membranophoridium aspinatum, Gerlach, 1961 (pl.29, fig.7), ex Gocht, 1969]
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Original description: [Gerlach, 1961]: (Translation: Stover and Evitt, 1978, p. 64):
Description:
A genus with the characteristics of the Family Hystrichosphaeridae and the following distinctions: thecal outline oval or circular; however, dominantly semicircular owing to the loss of the apical polar cap. Lower, in contrast to upper side, bordered by two, parallel, more or less low, meridionally trending, thorny fringes that may be interrupted repeatedly. Fringes not joined at antapex , often drawn out into two long lobes of unequal length. Lower side of the theca weakly depressed longitudinally.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Emended description:
Stover and Evitt, 1978:
Synopsis:
Cysts proximochorate, body lenticular; endophragm and periphragm appressed middorsally and midventrally, separated elsewhere to form mainly lateral pericoels and antapical lobations; archeopyle apical, Type tA; parasulcal notch offset.
Description:
Shape: Lenticular, with apical and two antapical lobations; lateral margins continuous, or nearly so.
Wall relationships: Endophragm and periphragm appressed middorsally and midventrally, separated elsewhere to form mainly lateral pericoels and antapical lobations; apical pericoel present.
Wall features: No parasutural features. Antapical lobations broadly to narrowly rounded, occasionally attenuated, and generally of unequal length. Endophragm and periphragm smooth or faintly ornamented.
Paratabulation: Indicated by archeopyle only; formula unknown.
Archeopyle: Apical, Type (tA); principal archeopyle suture zigzag, parasulcal notch offset; operculum free, dorsal-ventral dimension less than lateral dimension.
Paracingulum: Generally not indicated.
Parasulcus: Apical position indicated by parasulcal notch.
Size: Intermediate to large.
Affinities:
Membranophoridium differs from Chiropteridium in having the margin of the periphragm smooth to slightly sinuous. In Chiropteridium, the periphragm forms proximally connected and occasionally isolated processes with complexly branched and/or irregularly incised distal ends. Additionally, slender isolated processes may occur on the middorsal and midventral surfaces on some forms of Chiropteridium; such processes are not present on Membranophoridium.
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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.
Membranophoridium Gerlach, 1961, emend. Stover and Evitt, 1978. Synopsis of Stover and Evitt (1978, p.64). Cysts proximochorate, body lenticular; endophragm and periphragm appressed middorsally and midventrally, separated elsewhere to form mainly lateral pericoels and antapical lobations, archeopyle apical, type (tA), parasulcal notch offset.
[Membranophoridium, Gerlach, 1961, p. 198-199; Emendation: Stover and Evitt, 1978, p. 64-65
Tax. jun. syn. of Chiropteridium, according to Brosius (1963, p.47) and Schindler (1992, p.202) - however, Lentin and Williams (1993, p.421) retained Membranophoridium.
Type species: Membranophoridium aspinatum, Gerlach, 1961 (pl.29, fig.7), ex Gocht, 1969]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Gerlach, 1961]: (Translation: Stover and Evitt, 1978, p. 64):
Description:
A genus with the characteristics of the Family Hystrichosphaeridae and the following distinctions: thecal outline oval or circular; however, dominantly semicircular owing to the loss of the apical polar cap. Lower, in contrast to upper side, bordered by two, parallel, more or less low, meridionally trending, thorny fringes that may be interrupted repeatedly. Fringes not joined at antapex , often drawn out into two long lobes of unequal length. Lower side of the theca weakly depressed longitudinally.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Emended description:
Stover and Evitt, 1978:
Synopsis:
Cysts proximochorate, body lenticular; endophragm and periphragm appressed middorsally and midventrally, separated elsewhere to form mainly lateral pericoels and antapical lobations; archeopyle apical, Type tA; parasulcal notch offset.
Description:
Shape: Lenticular, with apical and two antapical lobations; lateral margins continuous, or nearly so.
Wall relationships: Endophragm and periphragm appressed middorsally and midventrally, separated elsewhere to form mainly lateral pericoels and antapical lobations; apical pericoel present.
Wall features: No parasutural features. Antapical lobations broadly to narrowly rounded, occasionally attenuated, and generally of unequal length. Endophragm and periphragm smooth or faintly ornamented.
Paratabulation: Indicated by archeopyle only; formula unknown.
Archeopyle: Apical, Type (tA); principal archeopyle suture zigzag, parasulcal notch offset; operculum free, dorsal-ventral dimension less than lateral dimension.
Paracingulum: Generally not indicated.
Parasulcus: Apical position indicated by parasulcal notch.
Size: Intermediate to large.
Affinities:
Membranophoridium differs from Chiropteridium in having the margin of the periphragm smooth to slightly sinuous. In Chiropteridium, the periphragm forms proximally connected and occasionally isolated processes with complexly branched and/or irregularly incised distal ends. Additionally, slender isolated processes may occur on the middorsal and midventral surfaces on some forms of Chiropteridium; such processes are not present on Membranophoridium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Membranophoridium Gerlach, 1961, emend. Stover and Evitt, 1978. Synopsis of Stover and Evitt (1978, p.64). Cysts proximochorate, body lenticular; endophragm and periphragm appressed middorsally and midventrally, separated elsewhere to form mainly lateral pericoels and antapical lobations, archeopyle apical, type (tA), parasulcal notch offset.