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Ramidinium
From Williams et al., 2017:
[Ramidinium, Guerstein et al., 1998, p. 28.
Type species: Ramidinium tridens, Guerstein et al., 1998 (pl.1, figs.4-5 text-figs.2D-E)]
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Original description: [Guerstein et al., 1998]:
Diagnosis:
Areoligeracean proximochorate to usually chorate, acavate cysts, with processes that are primarily parasutural and typically irregularly branched.
Affinities:
Among areoligeraceans, Ramidinium is distinct in having parasutural, branched processes. Chiropteridium Gocht, 1960 is also an areoligeracean with some isolated processes but differs from Ramidinium in having proximally membranous, confluent septa that occur principally in the marginal areas. Schindler (1992) described five Chiropteridium morphotypes, each exhibiting four lateral, crest-like structures on the dorsal and ventral surfaces, extending meridionally from the apical to the antapical region. These structures in Chiropteridium may be parasutural in part, although this is not clear from published descriptions. Ramidinium has a more uniform distribution of processes, and the crest-like structures of Chiropteridium are absent or may be represented by the low ridges joining adjacent processes. These low ridges may be relicts of the membranes observed in Chiropteridium. Areoligera Leujene, Carpentier, 1938 is characterized by the presence of arcuate complexes and Glaphyrocysta Stover and Evitt, 1978 has processes that are predominantly marginate in position and typically nontabulat or intratabulate. Enneadocysta Stover and Williams, 1995 also has an apical archaeopyle and some dorsoventral compression, but differs from Ramidinium in having intratabular processes that, around the antapex, are apparently arranged in the partiform pattern. Cooksodinium Stover and Williams, 1995 differs from Ramidinium in having intratabular processes, which sometimes occur in penitabular complexis. Spiniferites Mantell, 1850 and Achomosphaera Evitt, 1963, which also have parasutural processes with furcate endings, are distinguished from Ramidiniu by having a precingular archaeopyle.
[Ramidinium, Guerstein et al., 1998, p. 28.
Type species: Ramidinium tridens, Guerstein et al., 1998 (pl.1, figs.4-5 text-figs.2D-E)]
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Original description: [Guerstein et al., 1998]:
Diagnosis:
Areoligeracean proximochorate to usually chorate, acavate cysts, with processes that are primarily parasutural and typically irregularly branched.
Affinities:
Among areoligeraceans, Ramidinium is distinct in having parasutural, branched processes. Chiropteridium Gocht, 1960 is also an areoligeracean with some isolated processes but differs from Ramidinium in having proximally membranous, confluent septa that occur principally in the marginal areas. Schindler (1992) described five Chiropteridium morphotypes, each exhibiting four lateral, crest-like structures on the dorsal and ventral surfaces, extending meridionally from the apical to the antapical region. These structures in Chiropteridium may be parasutural in part, although this is not clear from published descriptions. Ramidinium has a more uniform distribution of processes, and the crest-like structures of Chiropteridium are absent or may be represented by the low ridges joining adjacent processes. These low ridges may be relicts of the membranes observed in Chiropteridium. Areoligera Leujene, Carpentier, 1938 is characterized by the presence of arcuate complexes and Glaphyrocysta Stover and Evitt, 1978 has processes that are predominantly marginate in position and typically nontabulat or intratabulate. Enneadocysta Stover and Williams, 1995 also has an apical archaeopyle and some dorsoventral compression, but differs from Ramidinium in having intratabular processes that, around the antapex, are apparently arranged in the partiform pattern. Cooksodinium Stover and Williams, 1995 differs from Ramidinium in having intratabular processes, which sometimes occur in penitabular complexis. Spiniferites Mantell, 1850 and Achomosphaera Evitt, 1963, which also have parasutural processes with furcate endings, are distinguished from Ramidiniu by having a precingular archaeopyle.