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Riasanodinium
From Williams et al., 2017:
[Riasanodinium, Iosifova, 1992, p. 62
Type species: Riasanodinium fedorovae, Iosifova, 1992 (pl.9, figs.1a–b; text-figs.1a–b)]
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Original description: [Iosifova, 1992]:
Diagnosis:
Chorate, cavate cysts of ellipsoidal shape. Periphragm bearing intratabular processes, one on each paralamina. Reflected tabulation along processes 4`, ?6", 6c, 5-6"`, 1"". Processes hollow, closed at distal and open at proximal end. Inner body oval and nowhere in contact with periphragm.
Peri- and endoarcheopyle apical, with zig-zag margin.
Affinities:
Resembles genera Hystrichosphaeridium and Lithosphaeridium in apical archeopyle, intratabular processes and similar tabulation formula. Differs in cavateness and character of processes. Differs from cavate genus Palaeohystrichophora in type of archeopyle and in number and character of processes.
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Supplementary description:
Iosifova 1996, p. 229, 231: (translated)
Diagnosis:
Chorate, circumcavate, elongate ellipsoidal cysts. Periphragm alone forms intratabular processes, one per paraplate area. The process formula: 4`, ?6", 6c, 5-6"`, l"". Processes are hollow, closed distally. Inner body ellipsoidal. Peri-and endoarcheopyle apical, with zig-zag margin.
Affinities:
It resembles Aprobolocysta Duxbury, 1977 by the nature of the cyst wall, but differs from it by the type of archeopyle (simple apical instead apical with deep parasulcal notch) and in that the processes are plate-centred and it is possible to discern the gonyaulacoid process formula.
[Riasanodinium, Iosifova, 1992, p. 62
Type species: Riasanodinium fedorovae, Iosifova, 1992 (pl.9, figs.1a–b; text-figs.1a–b)]
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Original description: [Iosifova, 1992]:
Diagnosis:
Chorate, cavate cysts of ellipsoidal shape. Periphragm bearing intratabular processes, one on each paralamina. Reflected tabulation along processes 4`, ?6", 6c, 5-6"`, 1"". Processes hollow, closed at distal and open at proximal end. Inner body oval and nowhere in contact with periphragm.
Peri- and endoarcheopyle apical, with zig-zag margin.
Affinities:
Resembles genera Hystrichosphaeridium and Lithosphaeridium in apical archeopyle, intratabular processes and similar tabulation formula. Differs in cavateness and character of processes. Differs from cavate genus Palaeohystrichophora in type of archeopyle and in number and character of processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Supplementary description:
Iosifova 1996, p. 229, 231: (translated)
Diagnosis:
Chorate, circumcavate, elongate ellipsoidal cysts. Periphragm alone forms intratabular processes, one per paraplate area. The process formula: 4`, ?6", 6c, 5-6"`, l"". Processes are hollow, closed distally. Inner body ellipsoidal. Peri-and endoarcheopyle apical, with zig-zag margin.
Affinities:
It resembles Aprobolocysta Duxbury, 1977 by the nature of the cyst wall, but differs from it by the type of archeopyle (simple apical instead apical with deep parasulcal notch) and in that the processes are plate-centred and it is possible to discern the gonyaulacoid process formula.