Back
Achomosphaera fenestra
From Fensome et al., 2019:
Achomosphaera fenestra, Kirsch, 1991, p.54–55, pl.2, figs.4,6–12; text-figs.35a–b,36a–j.
Holotype: Kirsch, 1991, pl.2, figs.7–9. NIA.
Age: early to middle Campanian.
Locus typicus: Marienstein, Bavaria, Germany
---------------------------------------------------------------------------------------------------
Original description: [Kirsch, 1991, p. 54] (Translation: LPP):
Diagnosis:
Chorate cyst with smooth, ovoidal to subsphaerical central body and gonal, hollow, smooth, isolate standing processes which are distally trifiurcate and end in a perforate membrane. Apical processes connected septae-like by a thin membrane over the whole process length. Archaeopyle precingular. Characteristic is the varying shape of processes in the apical-, antapical- and cingular-regions.
Description: (annotated)
Cyst with smooth endo- and periphragm. Periphragm developing hollow processes. Cyst habitus ovoidal to subsphaerical. Apical and antapical processes may be connected by membranes. These may be perforate and reach up to the distal ends of the processes. Sulcal processes usually thin and bifid. Cingular processes hollow, tubiform and distally widened. Distal ends trifurcate, thickened and solid, connected by irregularly perforated membrane. Free ends slightly bifid or blunt. Longitudinal thickenings on processes may give the impression of striation. Perforations oval to subcircular, distal margin of processes irregularly dentate. Sulcal processes shorter, thin and distally blunted.
Archaeopyle precingular.
Dimensions:
Holotype: central bogy 48x50 µm, length of processes max. 20 µm.
Range: central body 50-70x42-50 µm, overall 90-104x80-94 µm, length of processes 18-30 µm (specimens measured = 8).
Achomosphaera fenestra, Kirsch, 1991, p.54–55, pl.2, figs.4,6–12; text-figs.35a–b,36a–j.
Holotype: Kirsch, 1991, pl.2, figs.7–9. NIA.
Age: early to middle Campanian.
Locus typicus: Marienstein, Bavaria, Germany
---------------------------------------------------------------------------------------------------
Original description: [Kirsch, 1991, p. 54] (Translation: LPP):
Diagnosis:
Chorate cyst with smooth, ovoidal to subsphaerical central body and gonal, hollow, smooth, isolate standing processes which are distally trifiurcate and end in a perforate membrane. Apical processes connected septae-like by a thin membrane over the whole process length. Archaeopyle precingular. Characteristic is the varying shape of processes in the apical-, antapical- and cingular-regions.
Description: (annotated)
Cyst with smooth endo- and periphragm. Periphragm developing hollow processes. Cyst habitus ovoidal to subsphaerical. Apical and antapical processes may be connected by membranes. These may be perforate and reach up to the distal ends of the processes. Sulcal processes usually thin and bifid. Cingular processes hollow, tubiform and distally widened. Distal ends trifurcate, thickened and solid, connected by irregularly perforated membrane. Free ends slightly bifid or blunt. Longitudinal thickenings on processes may give the impression of striation. Perforations oval to subcircular, distal margin of processes irregularly dentate. Sulcal processes shorter, thin and distally blunted.
Archaeopyle precingular.
Dimensions:
Holotype: central bogy 48x50 µm, length of processes max. 20 µm.
Range: central body 50-70x42-50 µm, overall 90-104x80-94 µm, length of processes 18-30 µm (specimens measured = 8).