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Downiesphaeridium multispinosum
Cleistosphaeridium? multispinosum (Singh, 1964) Islam, 1993
NOW Cometodinium. Originally Baltisphaeridium (Appendix A), subsequently Cleistosphaeridium, thirdly Cleistosphaeridium?, fourthly Downiesphaeridium, fifthly (and now) Cometodinium.
Holotype: Singh, 1964, pl.20, fig.1
Locus typicus: Imperial Willington Well, Alberta, Canada
Stratum typicum: Middle Albian-Early Cenomanian
Original description: Singh, 1964, p.141-142: Baltisphaeridium multispinosum
Vesicle circular, thin-walled; length of processes about + of the diameter of the body, unbranched, thin, tapering and closed at the outer end, broadening slightly towards the base; some processes bifurcating at the tips.
Size range: Total diameter of the specimens 62-74 Ám, holotype 62 Ám. Diameter of the vesicle 40-50 Ám, holotype 41 Ám. Length of processes 10-15 Ám. Width of the processes 0.5-1 Ám, holotype 1 Ám.
Supplemental description: Brideaux, 1971, p.94: Cleistosphaeridium? multispinosum
Dinoflagellate cyst; outline ovoid, elongate in the longitudinal axis or nearly circular. Orientation in the absence of archeopyle formation uncertain; no cingulum or sulcus structure noted. Cyst ornamented with numerous, closely spaced, parallel-sided, thin fimbriate processes, closed apically and rounded, sometimes slightly bifid; processes 3--16 Ám Iong, not outlining any discernible pattern or reflected tabulation. Specimens having exactly similar morphology but possessing an apical archeopyle with zig-zag margin have been noted rarely.
Dimensions: Maximum diameter on 37 measured specimens, 24--59 Ám; minimum diameter on 24 measured specimens, 18--59 Ám. Total of 50 specimens recorded, many more observed.
Affinities:
Brideaux, 1971, p.94: Cleistosphaeridium? multispinosum
Specimens illustrated by Singh (1964) are identical in morphology with forms encountered here. The form called ?C. aciculare by Davey (1969) is likely a partial synonym, the processes and other morphology (Pl.6, fig.11) being consistent with the material recorded from Alberta. The writer has had the opportunity of examining material from the samples studied by Davey (1969) but has only been able to locate a few specimens for comparison. Hence the two species are only tentatively synonymized.
The form illustrated as Comefodinium sp. Sarjeant in Davey, et al., 1966, p.212; Pl.22, fig.6, and that figured as Cometodinium obscurum Deflandre and Courteville 1939 in Clarke and Verdier, p.35; Pl.10, fig.3 and Pl.11, fig.9, also appear similar to Cleistosphaeridium multispinosum (Singh), but material is not available for direct comparison.
NOW Cometodinium. Originally Baltisphaeridium (Appendix A), subsequently Cleistosphaeridium, thirdly Cleistosphaeridium?, fourthly Downiesphaeridium, fifthly (and now) Cometodinium.
Holotype: Singh, 1964, pl.20, fig.1
Locus typicus: Imperial Willington Well, Alberta, Canada
Stratum typicum: Middle Albian-Early Cenomanian
Original description: Singh, 1964, p.141-142: Baltisphaeridium multispinosum
Vesicle circular, thin-walled; length of processes about + of the diameter of the body, unbranched, thin, tapering and closed at the outer end, broadening slightly towards the base; some processes bifurcating at the tips.
Size range: Total diameter of the specimens 62-74 Ám, holotype 62 Ám. Diameter of the vesicle 40-50 Ám, holotype 41 Ám. Length of processes 10-15 Ám. Width of the processes 0.5-1 Ám, holotype 1 Ám.
Supplemental description: Brideaux, 1971, p.94: Cleistosphaeridium? multispinosum
Dinoflagellate cyst; outline ovoid, elongate in the longitudinal axis or nearly circular. Orientation in the absence of archeopyle formation uncertain; no cingulum or sulcus structure noted. Cyst ornamented with numerous, closely spaced, parallel-sided, thin fimbriate processes, closed apically and rounded, sometimes slightly bifid; processes 3--16 Ám Iong, not outlining any discernible pattern or reflected tabulation. Specimens having exactly similar morphology but possessing an apical archeopyle with zig-zag margin have been noted rarely.
Dimensions: Maximum diameter on 37 measured specimens, 24--59 Ám; minimum diameter on 24 measured specimens, 18--59 Ám. Total of 50 specimens recorded, many more observed.
Affinities:
Brideaux, 1971, p.94: Cleistosphaeridium? multispinosum
Specimens illustrated by Singh (1964) are identical in morphology with forms encountered here. The form called ?C. aciculare by Davey (1969) is likely a partial synonym, the processes and other morphology (Pl.6, fig.11) being consistent with the material recorded from Alberta. The writer has had the opportunity of examining material from the samples studied by Davey (1969) but has only been able to locate a few specimens for comparison. Hence the two species are only tentatively synonymized.
The form illustrated as Comefodinium sp. Sarjeant in Davey, et al., 1966, p.212; Pl.22, fig.6, and that figured as Cometodinium obscurum Deflandre and Courteville 1939 in Clarke and Verdier, p.35; Pl.10, fig.3 and Pl.11, fig.9, also appear similar to Cleistosphaeridium multispinosum (Singh), but material is not available for direct comparison.