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Prolixosphaeridium deirense
Prolixosphaeridium deirense Davey et al., 1966; Emendation: Harding, 1990b, p.46–47, as Prolixosphaeridium deirense.
Originally (and now) Prolixosphaeridium deirense, subsequently Prolixosphaeridium parvispinum ssp. deirense. Below, 1982 transferred this taxon to Prolixosphaeridium parvispinum (Deflandre, 1937) Davey et al., 1969, as a subspecies; however, Lentin and Williams, 1985 agreed with Davey and Verdier, 1974 and indicated Prolixosphaeridium parvispinum as the type species of Prolixosphaeridium.
Taxonomic senior synonym (at specific and varietal ranks): Hystrichosphaeridium xanthiopyxides var. parvispinum (as and now Prolixosphaeridium parvispinum), according to Davey and Verdier (1974, p.636–637) — however, Harding (1990b, p.46) retained Prolixosphaeridium deirense.
Holotype: Davey et al., 1966, pl.3, fig.2; text-fig.45; Fauconnier and Masure, 2004, pl.65, fig.3.
Locus typicus: Speeton Clay, West Heslerton, England
Stratum typicum: Middle Barremian
Original diagnosis: Davey et al., 1966, p.172
A Prolixosphaeridium having an elongate ovoidal central body bearing 60-65 processes. Processes simply or briefly bifurcate (bifurcation unequally long), closed proximally, dominantly or constantly closed distally. Two processes occupying antapical pole; remaining processes showing alignment in rows, encirceling test and offset at a position corresponding to the sulcus. Apex typically lost in archaeopyle formation; about six rows of processes present between archaeopyle and antapex, gap between third and fourth row probably corresponding to cingulum. Test surface granular and bearing dense cover of very short spinelets.
Original description: Davey et al., 1966, p.172
The distribution of the processes on the epitheca is into three rows; these appear to respectively comprise 9, 10, and 10 processes. Distribution of processes on the hypotheca was less easily determined. Two rows of processes were present posterior to the presumed cingulum, each apparently comprising 9 processes; and some 9 further processes clustered round the antapex, probably but not certainly representing a sixth process row.
Emended diagnosis: Harding, 1990, p.46-47
Shape: Ambitus prolate ovoidal, length: width ratio--2:1. hypocyst apparently longer than epicyst. Apical paraplates greatly reduced in size with respect to total cyst dimensions. Strong dorso-ventral compression unlikely as cyst found in variety of orientations.
Phragma: Differentiated autophragm 1 µm thick. Surface sculpture is essentially comprised of a pseudoreticulum, through the lumina of which protrude clavulae ( c. 0.5 µm dia.), giving rise to a granular aspect under the light microscope. In certain places the clavulae are elongated and fuse with neighbouring ones to form solid cylindrical processes. The processes are nontabular and acuminate. Those specimens with a less dense covering of processes (< 50) possess wider processes (> 2 µm dia.), those more densely covered (c. 60) have narrower processes (< 2 µm dia.).
Paratabulation: Unknown but consistently shows only 5 precingular paraplates and an ai all separated by accessory sutures. This may indicate fusion of two precingular paraplates (see Evitt, 1985).
Archaeopyle: Type (tA), presumably involving four apicals as a free, simple polyplacoid operculum.
Accessory archaeopyle sutures developed in precingular paraplate series.
Paracingulum: Undifferentiated.
Parasulcus: Only shown by position of ai after archaeopyle formation and by slight reduction of process length.
Dimensions: Body length, less operculum (59) 49.4 (42) µm. Body width (32) 25.5 (22) µm. Process length (15) 9 (7) µm. Specimens = 21 (15).
Originally (and now) Prolixosphaeridium deirense, subsequently Prolixosphaeridium parvispinum ssp. deirense. Below, 1982 transferred this taxon to Prolixosphaeridium parvispinum (Deflandre, 1937) Davey et al., 1969, as a subspecies; however, Lentin and Williams, 1985 agreed with Davey and Verdier, 1974 and indicated Prolixosphaeridium parvispinum as the type species of Prolixosphaeridium.
Taxonomic senior synonym (at specific and varietal ranks): Hystrichosphaeridium xanthiopyxides var. parvispinum (as and now Prolixosphaeridium parvispinum), according to Davey and Verdier (1974, p.636–637) — however, Harding (1990b, p.46) retained Prolixosphaeridium deirense.
Holotype: Davey et al., 1966, pl.3, fig.2; text-fig.45; Fauconnier and Masure, 2004, pl.65, fig.3.
Locus typicus: Speeton Clay, West Heslerton, England
Stratum typicum: Middle Barremian
Original diagnosis: Davey et al., 1966, p.172
A Prolixosphaeridium having an elongate ovoidal central body bearing 60-65 processes. Processes simply or briefly bifurcate (bifurcation unequally long), closed proximally, dominantly or constantly closed distally. Two processes occupying antapical pole; remaining processes showing alignment in rows, encirceling test and offset at a position corresponding to the sulcus. Apex typically lost in archaeopyle formation; about six rows of processes present between archaeopyle and antapex, gap between third and fourth row probably corresponding to cingulum. Test surface granular and bearing dense cover of very short spinelets.
Original description: Davey et al., 1966, p.172
The distribution of the processes on the epitheca is into three rows; these appear to respectively comprise 9, 10, and 10 processes. Distribution of processes on the hypotheca was less easily determined. Two rows of processes were present posterior to the presumed cingulum, each apparently comprising 9 processes; and some 9 further processes clustered round the antapex, probably but not certainly representing a sixth process row.
Emended diagnosis: Harding, 1990, p.46-47
Shape: Ambitus prolate ovoidal, length: width ratio--2:1. hypocyst apparently longer than epicyst. Apical paraplates greatly reduced in size with respect to total cyst dimensions. Strong dorso-ventral compression unlikely as cyst found in variety of orientations.
Phragma: Differentiated autophragm 1 µm thick. Surface sculpture is essentially comprised of a pseudoreticulum, through the lumina of which protrude clavulae ( c. 0.5 µm dia.), giving rise to a granular aspect under the light microscope. In certain places the clavulae are elongated and fuse with neighbouring ones to form solid cylindrical processes. The processes are nontabular and acuminate. Those specimens with a less dense covering of processes (< 50) possess wider processes (> 2 µm dia.), those more densely covered (c. 60) have narrower processes (< 2 µm dia.).
Paratabulation: Unknown but consistently shows only 5 precingular paraplates and an ai all separated by accessory sutures. This may indicate fusion of two precingular paraplates (see Evitt, 1985).
Archaeopyle: Type (tA), presumably involving four apicals as a free, simple polyplacoid operculum.
Accessory archaeopyle sutures developed in precingular paraplate series.
Paracingulum: Undifferentiated.
Parasulcus: Only shown by position of ai after archaeopyle formation and by slight reduction of process length.
Dimensions: Body length, less operculum (59) 49.4 (42) µm. Body width (32) 25.5 (22) µm. Process length (15) 9 (7) µm. Specimens = 21 (15).