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Cassiculosphaeridia ovalis
Cassiculosphaeridia ovalis, Harker and Sarjeant in Harker et al., 1990 ex Harker and Sarjeant, 1991
Harker and Sarjeant, 1991, validly published the species name by citing the place of lodgment of the holotype.
Holotype: Harker et al., 1990, pl.2, fig.7; text-fig.19
Locus typicus: La Riviere, Manitoba, Canada
Stratum typicum: Late Campanian
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Original description: Harker, Sarjeant and Caldwell, 1990, p. 87
Diagnosis:
Proximate cysts with an ovoidal ambitus, length being slightly greater than breadth. Phragma thin, composed of two closely adpressed layers; endophragm smooth to shagreenate, periphragm giving rise to short capitate spines supporting low connecting crests in a reticulum. An apical-antapical trend of the crests is evident on the hypotract and epitract; cingulum indicated by crests trending laterally around the equatorial region. Large precingular and postcingular paraplates are present; paratabulation apparently gonyaulacoid, but not determinable in full because of the dense reticulation.
Archaeopyle apical; parasutural notches occasionally developed and operculum frequently remaining attached.
Description:
The crests forming the reticulum appear as sinuous ridges on the surface. Nodes are formed in the ridges at the junction of a crest and a supporting spine. The structure of the spine-supported crests (Pl. 2, Fig. 12) is very similar to that of C. magna (Davey 1974, p. 46, Pl. 1, Fig. 3; and herein, Pl. 2, Fig. 10) and Alisocysta brevivallata (Pl. 5, Fig. 17). The position of the cingulum is indicated by laterally trending crests (three to four parallel rows) in the equatorial region. The presence and number of these crests are variable; they are not easily discernible in some specimens. The paratabulation could not be fully determined because of the complexity of the reticulation, yet the presence of large precingular and postcingular paraplates and a single antapical paraplate can be inferred from a more regularly spaced rectangular arrangement of the crests on the anterior and posterior sides of the cingulum (Pl. 2, Figs. 7, 11).
Dimensions:
Holotype: overall length 38 µm, breadth 33 µm, height of crests 1-1.5 µm, width 1-4 µm.
Range of 90 measurable specimens; overall length 38-55 µm, mean 49 µm; breadth 29-43 µm, mean 37 µm; height of crests 1-2.5 µm; width 1-4 µm.
Affinities:
This species is distinguished from all other species of Cassiculosphaeridia by its greater length: breadth ratio and the predominantly apical-antapical alignment of the crests. Ellipsoidictyum cinctum Klement 1960 and Ellipsodinium rugulosum Clarke and Verdier 1967 are very similar to this species; both differ in having a well-defined cingulum, the former also in being larger overall and having crests and a non-aligned reticulum, the latter in having a precingular archaeopyle and a closely spaced reticulation.
Harker and Sarjeant, 1991, validly published the species name by citing the place of lodgment of the holotype.
Holotype: Harker et al., 1990, pl.2, fig.7; text-fig.19
Locus typicus: La Riviere, Manitoba, Canada
Stratum typicum: Late Campanian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: Harker, Sarjeant and Caldwell, 1990, p. 87
Diagnosis:
Proximate cysts with an ovoidal ambitus, length being slightly greater than breadth. Phragma thin, composed of two closely adpressed layers; endophragm smooth to shagreenate, periphragm giving rise to short capitate spines supporting low connecting crests in a reticulum. An apical-antapical trend of the crests is evident on the hypotract and epitract; cingulum indicated by crests trending laterally around the equatorial region. Large precingular and postcingular paraplates are present; paratabulation apparently gonyaulacoid, but not determinable in full because of the dense reticulation.
Archaeopyle apical; parasutural notches occasionally developed and operculum frequently remaining attached.
Description:
The crests forming the reticulum appear as sinuous ridges on the surface. Nodes are formed in the ridges at the junction of a crest and a supporting spine. The structure of the spine-supported crests (Pl. 2, Fig. 12) is very similar to that of C. magna (Davey 1974, p. 46, Pl. 1, Fig. 3; and herein, Pl. 2, Fig. 10) and Alisocysta brevivallata (Pl. 5, Fig. 17). The position of the cingulum is indicated by laterally trending crests (three to four parallel rows) in the equatorial region. The presence and number of these crests are variable; they are not easily discernible in some specimens. The paratabulation could not be fully determined because of the complexity of the reticulation, yet the presence of large precingular and postcingular paraplates and a single antapical paraplate can be inferred from a more regularly spaced rectangular arrangement of the crests on the anterior and posterior sides of the cingulum (Pl. 2, Figs. 7, 11).
Dimensions:
Holotype: overall length 38 µm, breadth 33 µm, height of crests 1-1.5 µm, width 1-4 µm.
Range of 90 measurable specimens; overall length 38-55 µm, mean 49 µm; breadth 29-43 µm, mean 37 µm; height of crests 1-2.5 µm; width 1-4 µm.
Affinities:
This species is distinguished from all other species of Cassiculosphaeridia by its greater length: breadth ratio and the predominantly apical-antapical alignment of the crests. Ellipsoidictyum cinctum Klement 1960 and Ellipsodinium rugulosum Clarke and Verdier 1967 are very similar to this species; both differ in having a well-defined cingulum, the former also in being larger overall and having crests and a non-aligned reticulum, the latter in having a precingular archaeopyle and a closely spaced reticulation.