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Microdinium distinctum
Microdinium distinctum Davey, 1969
Originally (and now) Microdinium, subsequently Phanerodinium.
Questionable tax. sr. synonym of Microdinium? (as Phanerodinium) variospinum Davey, 1969, according to Below, 1987.
Questionable tax. sr. synonym of Microdinium glabrum Cookson and Eisenack, 1974, according to Below, 1987.
Questionable tax. sr. synonym of Microdinium (as Phanerodinium) opacum Brideaux, 1971, according to Below, 1987.
Below, 1987, transferred this species to Phanerodinium Deflandre, 1937. Lentin and Williams, 1989, retained it in Microdinium.
Holotype: Davey, 1969, p.2, figs.9-10, text-fig.13D
Locus typicus: Fetcham Mill, England
Stratum typicum: Early Cenomanian
Original diagnosis: Davey, 1969, p. 133
Shell subspherical, thick-walled, smooth. Sutural crests well developed bearing short, broad, flat-topped spines. Reflected tabulation I, oa, 6", 6""", 1p, 1""""; plates 1" and 6" very reduced and cingular plates absent. Cingulum broad, weakly laevo-rotatory.
Original description: Davey, 1969, p. 133-134
The shell wall is relatively thick, c. 1 Ám, and develops pronounced ridges at the plate boundaries. The sutural spines are closely set, very broad and flat distally.
The precingular plates are generally smaller than the postcingular plates. Plates 1" and 6" are small and appear as slight projections in the ventral area. This is widest posteriorly and is open anteriorly. The apical plate is six-sided and is lost in archaeopyle formation. The archaeopyle possesses slits extending posteriorly between the precingular plates.
Originally (and now) Microdinium, subsequently Phanerodinium.
Questionable tax. sr. synonym of Microdinium? (as Phanerodinium) variospinum Davey, 1969, according to Below, 1987.
Questionable tax. sr. synonym of Microdinium glabrum Cookson and Eisenack, 1974, according to Below, 1987.
Questionable tax. sr. synonym of Microdinium (as Phanerodinium) opacum Brideaux, 1971, according to Below, 1987.
Below, 1987, transferred this species to Phanerodinium Deflandre, 1937. Lentin and Williams, 1989, retained it in Microdinium.
Holotype: Davey, 1969, p.2, figs.9-10, text-fig.13D
Locus typicus: Fetcham Mill, England
Stratum typicum: Early Cenomanian
Original diagnosis: Davey, 1969, p. 133
Shell subspherical, thick-walled, smooth. Sutural crests well developed bearing short, broad, flat-topped spines. Reflected tabulation I, oa, 6", 6""", 1p, 1""""; plates 1" and 6" very reduced and cingular plates absent. Cingulum broad, weakly laevo-rotatory.
Original description: Davey, 1969, p. 133-134
The shell wall is relatively thick, c. 1 Ám, and develops pronounced ridges at the plate boundaries. The sutural spines are closely set, very broad and flat distally.
The precingular plates are generally smaller than the postcingular plates. Plates 1" and 6" are small and appear as slight projections in the ventral area. This is widest posteriorly and is open anteriorly. The apical plate is six-sided and is lost in archaeopyle formation. The archaeopyle possesses slits extending posteriorly between the precingular plates.