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Scriniodinium glabrum
Scriniodinium glabrum (Duxbury, 1977) Jan du Chêne et al., 1986
Now Athigmatocysta. Originally (and now) Athigmatocysta, subsequently Endoscrinium, thirdly Scriniodinium. Lentin and Williams, 1989 retained this species in Endoscrinium (Klement, 1960) Vozzhennikova, 1967. Harding, 1990 retained it in Athigmatocysta Duxbury, 1977. This combination is not attributable to Stover and Williams, 1987.
Holotype: Duxbury, 1977, pl.11, figs.1,6, text-fig.3; Jan du Chêne et al., 1986, pl.111, figs.9-10
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Hauterivian
Original diagnosis: Duxbury, 1977, p. 24: Athigmatocysta glabra
A thin-walled, distinctly bi-layered proximo-cavate cyst. The tabulation ?4", 6", 6c, 6""", 1p, 1pv, 1"""" is outlined on the periphragm by distinctly denticulate sutural crests of variable height. The endophragm is ellipsoidal, slightly longer than broad and produced into a low apical prominence which reflects the short apical horn borne by the periphragm. Both periphragm and endophragm are smooth. Archeopyle precingular, formed by loss of plate 3".
Observed Dimensions: Holotype 94 x 79 µm. Range 94(83)69 x 71(70)61 µm.
Remark: Duxbury, 1977, p. 24: Athigmatocysta glabra
This is a thin-walled form and is usually distorted. In better preserved specimens, there is apparently complete cavation between the endophragm and periphragm. Obviously there must be some connection between the body layers in order to maintain the position of the endoblast within the periblast. Unfortunately, no such connection was apparent here. The endophragm commonly exhibits an archeopyle reflecting that in the periphragm formed by loss of plate 3". It is much less angular than 3".
Now Athigmatocysta. Originally (and now) Athigmatocysta, subsequently Endoscrinium, thirdly Scriniodinium. Lentin and Williams, 1989 retained this species in Endoscrinium (Klement, 1960) Vozzhennikova, 1967. Harding, 1990 retained it in Athigmatocysta Duxbury, 1977. This combination is not attributable to Stover and Williams, 1987.
Holotype: Duxbury, 1977, pl.11, figs.1,6, text-fig.3; Jan du Chêne et al., 1986, pl.111, figs.9-10
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Hauterivian
Original diagnosis: Duxbury, 1977, p. 24: Athigmatocysta glabra
A thin-walled, distinctly bi-layered proximo-cavate cyst. The tabulation ?4", 6", 6c, 6""", 1p, 1pv, 1"""" is outlined on the periphragm by distinctly denticulate sutural crests of variable height. The endophragm is ellipsoidal, slightly longer than broad and produced into a low apical prominence which reflects the short apical horn borne by the periphragm. Both periphragm and endophragm are smooth. Archeopyle precingular, formed by loss of plate 3".
Observed Dimensions: Holotype 94 x 79 µm. Range 94(83)69 x 71(70)61 µm.
Remark: Duxbury, 1977, p. 24: Athigmatocysta glabra
This is a thin-walled form and is usually distorted. In better preserved specimens, there is apparently complete cavation between the endophragm and periphragm. Obviously there must be some connection between the body layers in order to maintain the position of the endoblast within the periblast. Unfortunately, no such connection was apparent here. The endophragm commonly exhibits an archeopyle reflecting that in the periphragm formed by loss of plate 3". It is much less angular than 3".