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Amphorulacysta expirata
Amphorulacysta expirata, (Davey, 1982b, p.28–29, pl. 8, figs.13–16), Williams and Fensome 2016, p.139.
Originally Egmontodinium, subsequently Amphorula (generic name illegitimate), thirdly (and now) Amphorulacysta? Questionable assignment: Williams and Fensome (2016, p.139).
Holotype: Davey, 1982b, pl.8, figs.13–14.
Locus typicus: Tilly Whim Caves, Dorset, England
Age: early Portlandian–earliest Ryazanian.
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Original description as Egmontodinium expiratum: [Davey, 1982, p. 28]:
Diagnosis:
Shape: Cysts ovoidal to elongate with rounded apices. Dorso-ventral flattening is only minor.
Wall: The wall is apparently two-layered and of moderate thickness; it is smooth to scabrate. The crests and processes are smooth.
Paratabulation: This is only partly defined by low parasutural crests and appears to be 4", 6", 6""", 1p, 1"""". The crests are basically penitabular although the precingular crests may be parasutural at or towards the paracingular region and diverge from here towards the apices. The limits of the parasulcus may be also, partly defined, as may the paraplates 1"""and 1p. Penitabular crests define the position of the antapical paraplate (1""""). The boundaries of the paracingulum are practically absent.
Processes: These are located on the crests and, although are of variable width, they are usually broadly membranous. Distally the gonal processes are briefly trifurcate and the parasutural processes briefly bifurcate. Rarely isolated processes are present in parasutural or penitabular positions, particularly in the paracingular region.
Archaeopyle: Apical; margin strongly zig-zag with a deep parasulcal notch. The archaeopyle breakage occurs midway between the penitabular crests of the apical and precingular series.
Description:
The crests are sometimes striate or vacuolate and vary in height from simple ridges to membranous crests. The majority of the processes are extensions of the crests and are linked by the crests. The crests are usually best developed and most noticeable in the antapical region. Often in the parasulcal and apical regions it is difficult to determine whether or not the crests are parasutural or penitabular. The apical region is rarely seen because it is detached in archaeopyle formation.
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Courtinat, 1989, p. 174:
Remark:
A. expirata presents arched or horseshoe-shaped penitabular crests as well as rare paracingular processes. These two characteristics are typical of the genus Amphorula, whilst the genus Egmontodinium Gitmez and Sarjeant possesses low sutural crests. For this reason, the new combination A. expirata is proposed. This rare species is until now only known from the boreal Portlandian of England and Denmark.
Originally Egmontodinium, subsequently Amphorula (generic name illegitimate), thirdly (and now) Amphorulacysta? Questionable assignment: Williams and Fensome (2016, p.139).
Holotype: Davey, 1982b, pl.8, figs.13–14.
Locus typicus: Tilly Whim Caves, Dorset, England
Age: early Portlandian–earliest Ryazanian.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Egmontodinium expiratum: [Davey, 1982, p. 28]:
Diagnosis:
Shape: Cysts ovoidal to elongate with rounded apices. Dorso-ventral flattening is only minor.
Wall: The wall is apparently two-layered and of moderate thickness; it is smooth to scabrate. The crests and processes are smooth.
Paratabulation: This is only partly defined by low parasutural crests and appears to be 4", 6", 6""", 1p, 1"""". The crests are basically penitabular although the precingular crests may be parasutural at or towards the paracingular region and diverge from here towards the apices. The limits of the parasulcus may be also, partly defined, as may the paraplates 1"""and 1p. Penitabular crests define the position of the antapical paraplate (1""""). The boundaries of the paracingulum are practically absent.
Processes: These are located on the crests and, although are of variable width, they are usually broadly membranous. Distally the gonal processes are briefly trifurcate and the parasutural processes briefly bifurcate. Rarely isolated processes are present in parasutural or penitabular positions, particularly in the paracingular region.
Archaeopyle: Apical; margin strongly zig-zag with a deep parasulcal notch. The archaeopyle breakage occurs midway between the penitabular crests of the apical and precingular series.
Description:
The crests are sometimes striate or vacuolate and vary in height from simple ridges to membranous crests. The majority of the processes are extensions of the crests and are linked by the crests. The crests are usually best developed and most noticeable in the antapical region. Often in the parasulcal and apical regions it is difficult to determine whether or not the crests are parasutural or penitabular. The apical region is rarely seen because it is detached in archaeopyle formation.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Courtinat, 1989, p. 174:
Remark:
A. expirata presents arched or horseshoe-shaped penitabular crests as well as rare paracingular processes. These two characteristics are typical of the genus Amphorula, whilst the genus Egmontodinium Gitmez and Sarjeant possesses low sutural crests. For this reason, the new combination A. expirata is proposed. This rare species is until now only known from the boreal Portlandian of England and Denmark.