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Fibrocysta bipolaris

Fibrocysta bipolaris (Cookson and Eisenack, 1965) Stover and Evitt, 1978

Originally Cordosphaeridium, subsequently Lanternosphaeridium, thirdly Amphorosphaeridium, fourthly (and now) Fibrocysta.
Holotype: Cookson and Eisenack, 1965, pl.16, fig.8
Paratype: Cookson and Eisenack, 1965
Locus typicus: 9 miles SW of Casterton, SW Victoria, Australia
Stratum typicum: Early Eocene

Original description: Cookson and Eisenack, 1965, p.135: Cordosphaeridium bipolare
Shell typically oval, well-covered with narrow, solid, unbranched appendages of varying length, and width. Usually the appendages narrow somewhat from broadish bases to widen distally to shallow funnel-shaped apices, the recurved edges of which may bear minute hair-like branches. In the larger appendages fine, longitudinal fibrils may be seen. The shell is bipolar, being characterized by the development of a distinctive apical and antapical appendage. The apical appendage is relatively short and broad, solid, densely granular and with a bluntish tip. It may be simple or with one or two short, slender, lateral branches. In the type specimen ([Cookson and Eisenack, 1965] Pl. 16, fig. 8) it appears to be connected with three broad, flattened, longitudinally striated appendages. The antapical appendage is longer than the neighbouring ones, unstriated, unbranched with approximately straight sides and a pointed tip.
The surface of the shell is densely granular with a linear arrangement evident near the bases of the appendages. A large archeopyle extends from close to the apical pole to the equatorial region of one surface.
Size: Holotype: overall length 128 Ám, overall width 90 Ám, central body 80 x 62 Ám, length of apical appendage 17 Ám, length of antapical appendage 29 Ám. Range: overall length 124-128 Ám, overall width 88-98 Ám, central body 80-90 x 57-70 Ám, length of apical appendage 12-17 Ám, length of antapical appendage 20-33 Ám.
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