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Balteocysta perforata
Balteocysta perforata, (Davey, 1978), (Wilson and Clowes, 1980)
Nomenclatural sr. synonym of Balteocysta rotula Stover and Evitt, 1978, which has the same holotype.
Lentin and Williams, 1981, assumed that Davey named this species for the perforations it possesses: since it was "perforate", he used the Latin perforare, which is equivalent to the English infinitive "perforate"; the Latin for the past participle is perforatus. Therefore, the correct orthography of the specific epithet is perforata and not perforare, since Davey indicated in his text that the name was not composed arbitrarily. For discussion of name see Aiora perforata.
Holotype: Cookson and Eisenack, 1960, pl.2, fig.17 (as Aiora fenestrata), designated by Davey, 1978.
Locus typicus: Carnavron Basin, W Australia.
Stratum typicum: Turonian.
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Original description as Aiora perforata: [Davey, 1978, p. 892]:
Diagnosis:
A species of Aiora possessing a smooth, thin-walled shell of subcircular outline from which arise approximately five flat equally spaced processes or process groups. These may subdivide proximally and/or medially to give rise to two or more branches diverging in the plane of flattening, and distally in a complex manner to form a fenestrate membrane. The fenestrations are subcircular to rounded-polygonal in outline and tend to become smaller distally. The membrane links adjacent processes and forms a continuously circular network around the shell. The outer extremity of the membrane is smooth and tends to be slightly recurved.
Description:
The exact nature of the processes is difficult to determine but they appear to be single layered, flattened, or membranous structures. Five of these processes are present in the illustrated specimen. Here two appear to arise on opposite sides of the shell from high up on the precingular plates; one is cingular arising from the left margin, one is postcingular arising from the right margin and one is antapical. An alternative way of describing this cyst would be to consider its basic morphology to be comparable to that of a Pterospermella species possessing a fenestrate periphragm wing. Approximately five large proximal perforations should then be envisaged with an increase in number, but decrease in size of the fenestration as the outer limit of the wing is approached. No direct relationship between Aiora and Pterospermella, however, is in any way implied here.
Dimensions:
From Cookson and Eisenack, 1960 holotype (measured from illustration pl. 2, fig. 17), shell diameter 50x65 µm overall diameter 115x150 µm; range, shell diameter 50-80 µm, overall diameter 120-160 µm. Figured specimen, Plate 1, Figures 2, 3 shell diameter 51x59 µm, overall diameter 120x130 µm.
Nomenclatural sr. synonym of Balteocysta rotula Stover and Evitt, 1978, which has the same holotype.
Lentin and Williams, 1981, assumed that Davey named this species for the perforations it possesses: since it was "perforate", he used the Latin perforare, which is equivalent to the English infinitive "perforate"; the Latin for the past participle is perforatus. Therefore, the correct orthography of the specific epithet is perforata and not perforare, since Davey indicated in his text that the name was not composed arbitrarily. For discussion of name see Aiora perforata.
Holotype: Cookson and Eisenack, 1960, pl.2, fig.17 (as Aiora fenestrata), designated by Davey, 1978.
Locus typicus: Carnavron Basin, W Australia.
Stratum typicum: Turonian.
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Original description as Aiora perforata: [Davey, 1978, p. 892]:
Diagnosis:
A species of Aiora possessing a smooth, thin-walled shell of subcircular outline from which arise approximately five flat equally spaced processes or process groups. These may subdivide proximally and/or medially to give rise to two or more branches diverging in the plane of flattening, and distally in a complex manner to form a fenestrate membrane. The fenestrations are subcircular to rounded-polygonal in outline and tend to become smaller distally. The membrane links adjacent processes and forms a continuously circular network around the shell. The outer extremity of the membrane is smooth and tends to be slightly recurved.
Description:
The exact nature of the processes is difficult to determine but they appear to be single layered, flattened, or membranous structures. Five of these processes are present in the illustrated specimen. Here two appear to arise on opposite sides of the shell from high up on the precingular plates; one is cingular arising from the left margin, one is postcingular arising from the right margin and one is antapical. An alternative way of describing this cyst would be to consider its basic morphology to be comparable to that of a Pterospermella species possessing a fenestrate periphragm wing. Approximately five large proximal perforations should then be envisaged with an increase in number, but decrease in size of the fenestration as the outer limit of the wing is approached. No direct relationship between Aiora and Pterospermella, however, is in any way implied here.
Dimensions:
From Cookson and Eisenack, 1960 holotype (measured from illustration pl. 2, fig. 17), shell diameter 50x65 µm overall diameter 115x150 µm; range, shell diameter 50-80 µm, overall diameter 120-160 µm. Figured specimen, Plate 1, Figures 2, 3 shell diameter 51x59 µm, overall diameter 120x130 µm.