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Adnatosphaeridium vetusculum
Adnatosphaeridium vetusculum, Davey, 1974
NOW Nexosispinum. Originally Adnatosphaeridium, subsequently Systematophora, thirdly (and now) Nexosispinum, fourthly Kiokansium.
Holotype: Davey, 1974, pl.1, fig.2
Locus typicus: Speeton, England
Stratum typicum: Barremian
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Original description: Davey, 1974, p. 45
Diagnosis:
The cyst is sphaerical to subsphaerical, smooth and bears numerous complex rigid, solid processes. Process alignment is not apparent. All the processes on a specimen are generally of approximately the same width. Some are simple but more usually one anastomoses with its neighbour or neighbours either proximately, medially or distally. they terminate distally with a simple or complex bifurcation.
The archaeopyle appears to be apical with the operculum sometimes remaining attached.
Description:
Proximally the processes are usually about 1 µm wide; distally they assume various complex configurations. Rarely they are simple with a short distal bifurcation; more often one anastomoses with its neighbour immediately after leaving the central body surface and bifurcates once or twice distally, or anastomosis of two or more processes take place medially or distally. In the last case bifurcations are still present distally together occasionally with very fine tapering spines which may be blunted distally or terminate with a minute bifurcation.
Dimensions:
Central body diameter - range - 37(43.5)57 µm. Process length 8(11)17 µm.
NOW Nexosispinum. Originally Adnatosphaeridium, subsequently Systematophora, thirdly (and now) Nexosispinum, fourthly Kiokansium.
Holotype: Davey, 1974, pl.1, fig.2
Locus typicus: Speeton, England
Stratum typicum: Barremian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: Davey, 1974, p. 45
Diagnosis:
The cyst is sphaerical to subsphaerical, smooth and bears numerous complex rigid, solid processes. Process alignment is not apparent. All the processes on a specimen are generally of approximately the same width. Some are simple but more usually one anastomoses with its neighbour or neighbours either proximately, medially or distally. they terminate distally with a simple or complex bifurcation.
The archaeopyle appears to be apical with the operculum sometimes remaining attached.
Description:
Proximally the processes are usually about 1 µm wide; distally they assume various complex configurations. Rarely they are simple with a short distal bifurcation; more often one anastomoses with its neighbour immediately after leaving the central body surface and bifurcates once or twice distally, or anastomosis of two or more processes take place medially or distally. In the last case bifurcations are still present distally together occasionally with very fine tapering spines which may be blunted distally or terminate with a minute bifurcation.
Dimensions:
Central body diameter - range - 37(43.5)57 µm. Process length 8(11)17 µm.