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Melitasphaeridium
From Fensome et al., 2019:
Melitasphaeridium, Harland and Hill, 1979, p.38–39.
Type: Deflandre and Cookson, 1955, text-figs.23–26, as Hystrichosphaeridium choanophorum.
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Original description: [Harland and Hill, 1979]:
Diagnosis:
Small spherical cyst with a paratabulation, inferred from the process arrangement, of pr, 4`, 6``, 0-6c, 6```, 1p, 1````. Circular processes may ore may not be present. Periphragm and endophragm distinct and closely adpressed, only the periphragm makes up the hollow, tubular processes with open distal tips. Archeopyle precingular, possibly enlarged, formed by the loss of a single paraplate, ?3``.
Affinities:
Melitasphaeridium differs from Cordosphaeridium Eisenack 1963 by being small, in not possessing solid fibrous processes and in not having the complex fibrous wall structure. The recently described genus Bacchidinium Davey (in press) is very similar especially in size, general appearance and in the possession of a precingular archaopyle, if differs, however, in having solid processes. The genus Kleithriasphaeridium Davey 1974 is also similar but differs in possessing cingular processes, being bigger and having striated processes often linked proximally.
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Modified description:
Stover and Williams 1987, p. 157-158:
Synopsis:
Cysts skolochorate, body subspherical, bearing 19 to 25, hollow, intratabular processes with strongly aculeate or slightly expanded distally to funnel-shaped tips with smooth or denticulate to aculeate margins; paratabulation gonyaulacacean, indicated by processes; archeopyle precingular, type P, operculum free.
Description:
Shape: Skolochorate, body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: No parasutural features. Processes intratabular, tubular and narrow relative to cyst size; tips of processes slightly expanded to funnel-shaped distally and with entire, denticulate, setate or aculeate margins. Periphragm smooth or faintly ornamented.
Archeopyle: Precingular, Type P (3``); operculum free.
Paratabulation: Expressed by intratabular processes; gonyaulacacean, process formula: 0-1pr, 4`, 6``, 0-6c, 6```, 1p, 1````.
Paracingulum: Indicated by six processes or by the absence of processes.
Parasulcus: Not indicated.
Size: Intermediate, 55 µm to 75 µm, overall diameter.
Affinities:
Melitasphaeridium differs from Cordosphaeridium Eisenack 1963 emended Davey 1969 and Kleithriasphaeridium Davey 1974, which also have simple precingular archeopyles and intratabular processes, in possessing processes whose distal ends are modified into funnel-like structures, with or without marginal features.
In addition the processes on Melitasphaeridium are not fibrous as are those on Cordosphaeridium.
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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.
Melitasphaeridium Harland and Hill, 1979. According to Harland and Hill (1979, p38-39), Melitasphaeridium is a small spherical cyst with a paratabulation, inferred from the process arrangement, of pr, 4', 6", 0-6c, 6"' , 1p, 1''''. Cingular processes may or may not be present. Periphragm and endophragm distinct and closely adpressed, only the periphragm makes up the hollow, tubular processes with open distal tips. Archeopyle precingular, possibly enlarged, formed by the loss of a single paraplate ?3".
Melitasphaeridium, Harland and Hill, 1979, p.38–39.
Type: Deflandre and Cookson, 1955, text-figs.23–26, as Hystrichosphaeridium choanophorum.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Harland and Hill, 1979]:
Diagnosis:
Small spherical cyst with a paratabulation, inferred from the process arrangement, of pr, 4`, 6``, 0-6c, 6```, 1p, 1````. Circular processes may ore may not be present. Periphragm and endophragm distinct and closely adpressed, only the periphragm makes up the hollow, tubular processes with open distal tips. Archeopyle precingular, possibly enlarged, formed by the loss of a single paraplate, ?3``.
Affinities:
Melitasphaeridium differs from Cordosphaeridium Eisenack 1963 by being small, in not possessing solid fibrous processes and in not having the complex fibrous wall structure. The recently described genus Bacchidinium Davey (in press) is very similar especially in size, general appearance and in the possession of a precingular archaopyle, if differs, however, in having solid processes. The genus Kleithriasphaeridium Davey 1974 is also similar but differs in possessing cingular processes, being bigger and having striated processes often linked proximally.
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Modified description:
Stover and Williams 1987, p. 157-158:
Synopsis:
Cysts skolochorate, body subspherical, bearing 19 to 25, hollow, intratabular processes with strongly aculeate or slightly expanded distally to funnel-shaped tips with smooth or denticulate to aculeate margins; paratabulation gonyaulacacean, indicated by processes; archeopyle precingular, type P, operculum free.
Description:
Shape: Skolochorate, body subspherical.
Wall relationships: Endophragm and periphragm appressed between processes.
Wall features: No parasutural features. Processes intratabular, tubular and narrow relative to cyst size; tips of processes slightly expanded to funnel-shaped distally and with entire, denticulate, setate or aculeate margins. Periphragm smooth or faintly ornamented.
Archeopyle: Precingular, Type P (3``); operculum free.
Paratabulation: Expressed by intratabular processes; gonyaulacacean, process formula: 0-1pr, 4`, 6``, 0-6c, 6```, 1p, 1````.
Paracingulum: Indicated by six processes or by the absence of processes.
Parasulcus: Not indicated.
Size: Intermediate, 55 µm to 75 µm, overall diameter.
Affinities:
Melitasphaeridium differs from Cordosphaeridium Eisenack 1963 emended Davey 1969 and Kleithriasphaeridium Davey 1974, which also have simple precingular archeopyles and intratabular processes, in possessing processes whose distal ends are modified into funnel-like structures, with or without marginal features.
In addition the processes on Melitasphaeridium are not fibrous as are those on Cordosphaeridium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Melitasphaeridium Harland and Hill, 1979. According to Harland and Hill (1979, p38-39), Melitasphaeridium is a small spherical cyst with a paratabulation, inferred from the process arrangement, of pr, 4', 6", 0-6c, 6"' , 1p, 1''''. Cingular processes may or may not be present. Periphragm and endophragm distinct and closely adpressed, only the periphragm makes up the hollow, tubular processes with open distal tips. Archeopyle precingular, possibly enlarged, formed by the loss of a single paraplate ?3".