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Valensiella magna
Vallensiella magna (Davey, 1974) Courtinat, 1989; Emendation: Harding, 1990b, p.49, as Cassiculosphaeridia magna.
NOW Cassiculosphaeridia. Originally (and now) Cassiculosphaeridia, subsequently Valensiella. Slimani, 1994 retained this species in Cassiculosphaeridia
Holotype: Davey, 1974, pl.1, fig.6
Paratype: Davey, 1974
Locus typicus: Speeton, England
Stratum typicum: Barremian
Original description: Davey 1974, p. 46: Cassiculosphaeridia magna
Diagnosis: The cysts are subspherical to ovoidal, thick walled and of large size, with the outer wall giving rise to vermiform, anastomosing crests. The outer wall is smooth to lightly pitted. The positions of the crests vary and may form all gradations from a more or less closed network to a relatively open one; they are supported, especially where anastomosis takes place, by short stout processes which widen distally to develop the outer edge of the crest and also widen proximally before joining the cyst central body. The position of the crest may indicate the cingulum which occupies the widest portion of the cyst. The ratio of the hypotract to epitract is 2 to 2.5 to 1. An apical archaeopyle is typically developed, the operculum occasionally remaining in place.
Dimensions: Central body diameter: 68-92 µm; maximum height of the crests: 4-9 µm.
Original description: Davey, 1974, p.46: Cassiculosphaeridia magna
The crests in this species give the cyst a somewhat wrinkled appearance. They may be strongly or weakly developed and may occasionally be perforate. When the crests are relatively few in number, forming a relatively open network, the stronger crests run longitudinally along the cyst and terminate at the cingular region. The latter region sometimes possesses fewer crests than normal and is thus distinctive. The position of the cingulum allows the hypotract- epitract ratio to be calculated and indicates that the length of the postcingular region is 2 to 3 times greater than that of the precingular region. Definite signs of a tabulation are, however, usually absent. One specimen (pl. 1, fig. 7) does show a cingular and perhaps a mid-dorsal fold.
Emended diagnosis: Harding, 1990, p. 49: Cassiculosphaeridia magna
Shape: Ambitus oblate to subcircular. Thick-walled, robust cyst, greatest width in paracingular region. Hypocyst half as long again as the epicyst. Moderate dorso-ventral compression.
Phragma: Differentiated autophragm robust, up to 3 llm thick. In cross section consists of an imperforate internal layer, the main part of the wall is composed of partially fused sporopollenin granulae (up to 0.75 Ám in dia.). Distally the granulae fuse more completely leaving a punctate surface layer which is developed into "septa" up to 8 Ám high. The septa are flared proximally and distally and may be fenestrate. The septa are prone to oxidation damage which rounds off their distal extremities. The septa are generally non-tabular, in the form of a pseudoreticulation. Ectophragm is rarely preserved, though when present is--0.2-0.5 Ám thick and is a distal extension of the septa (Plate 30, Fig. 3. The ectocoel is partitioned, an ectocoelar area enclosed in each lumen of the pseudoreticulum.
Paratabulation: Only determined for the epicyst by studying the nature of the archaeopyle suture: pr, 4", 6", ai.
Archaeopyle: Type (tA), involving the apicals as a free, simple polyplacoid operculum.
Paracingulum: Usually undifferentiated, but sometimes delineated by quasi-parallel orientation of septa.
Parasulcus: Shown occasionally by slightly offset parasulcal notch.
Dimensions: Diameter (105) 95.6 (85) Ám. Specimens = 31 (10).
Affinities:
Davey 1974, p. 46: Cassiculosphaeridia magna
Cassiculosphaeridia magna is easily distinguished from C. reticulata Davey (1969) by its much greater size, the presence of strong processes supporting the crests and by its larger hypotract-epitract ratio.
NOW Cassiculosphaeridia. Originally (and now) Cassiculosphaeridia, subsequently Valensiella. Slimani, 1994 retained this species in Cassiculosphaeridia
Holotype: Davey, 1974, pl.1, fig.6
Paratype: Davey, 1974
Locus typicus: Speeton, England
Stratum typicum: Barremian
Original description: Davey 1974, p. 46: Cassiculosphaeridia magna
Diagnosis: The cysts are subspherical to ovoidal, thick walled and of large size, with the outer wall giving rise to vermiform, anastomosing crests. The outer wall is smooth to lightly pitted. The positions of the crests vary and may form all gradations from a more or less closed network to a relatively open one; they are supported, especially where anastomosis takes place, by short stout processes which widen distally to develop the outer edge of the crest and also widen proximally before joining the cyst central body. The position of the crest may indicate the cingulum which occupies the widest portion of the cyst. The ratio of the hypotract to epitract is 2 to 2.5 to 1. An apical archaeopyle is typically developed, the operculum occasionally remaining in place.
Dimensions: Central body diameter: 68-92 µm; maximum height of the crests: 4-9 µm.
Original description: Davey, 1974, p.46: Cassiculosphaeridia magna
The crests in this species give the cyst a somewhat wrinkled appearance. They may be strongly or weakly developed and may occasionally be perforate. When the crests are relatively few in number, forming a relatively open network, the stronger crests run longitudinally along the cyst and terminate at the cingular region. The latter region sometimes possesses fewer crests than normal and is thus distinctive. The position of the cingulum allows the hypotract- epitract ratio to be calculated and indicates that the length of the postcingular region is 2 to 3 times greater than that of the precingular region. Definite signs of a tabulation are, however, usually absent. One specimen (pl. 1, fig. 7) does show a cingular and perhaps a mid-dorsal fold.
Emended diagnosis: Harding, 1990, p. 49: Cassiculosphaeridia magna
Shape: Ambitus oblate to subcircular. Thick-walled, robust cyst, greatest width in paracingular region. Hypocyst half as long again as the epicyst. Moderate dorso-ventral compression.
Phragma: Differentiated autophragm robust, up to 3 llm thick. In cross section consists of an imperforate internal layer, the main part of the wall is composed of partially fused sporopollenin granulae (up to 0.75 Ám in dia.). Distally the granulae fuse more completely leaving a punctate surface layer which is developed into "septa" up to 8 Ám high. The septa are flared proximally and distally and may be fenestrate. The septa are prone to oxidation damage which rounds off their distal extremities. The septa are generally non-tabular, in the form of a pseudoreticulation. Ectophragm is rarely preserved, though when present is--0.2-0.5 Ám thick and is a distal extension of the septa (Plate 30, Fig. 3. The ectocoel is partitioned, an ectocoelar area enclosed in each lumen of the pseudoreticulum.
Paratabulation: Only determined for the epicyst by studying the nature of the archaeopyle suture: pr, 4", 6", ai.
Archaeopyle: Type (tA), involving the apicals as a free, simple polyplacoid operculum.
Paracingulum: Usually undifferentiated, but sometimes delineated by quasi-parallel orientation of septa.
Parasulcus: Shown occasionally by slightly offset parasulcal notch.
Dimensions: Diameter (105) 95.6 (85) Ám. Specimens = 31 (10).
Affinities:
Davey 1974, p. 46: Cassiculosphaeridia magna
Cassiculosphaeridia magna is easily distinguished from C. reticulata Davey (1969) by its much greater size, the presence of strong processes supporting the crests and by its larger hypotract-epitract ratio.