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Hystrichosphaera ramosa var. gracilis
Hystrichosphaera ramosa ssp. gracilis Davey and Williams 1966
Now Spiniferites ramosus ssp. gracilis. Orignally Hystrichosphaera ramosa var. gracilis, subsequently Spirliferites ramosus var. gracilis, thirdly (and now) Spiniferites ramosus ssp. gracilis.
Tax. jr. synonym of Hystrichosphaeridium plicatum Maier, 1959, according to Sarjeant, 1983, who noted that Hystrichosphaera ramosa var. gracilis (as Spiniferites ramosus ssp. gracilis) must be retained, since a taxon does not have priority outside its own rank.
Holotype: Davey and Williams, 1966, pl.1, fig.5; pl.5, fig.6; Bujak et al., 1980, pl.4, figs.1-2
Locus typicus: London Clay, Sheppey, Kent, England
Stratum typicum: Cenomanian-Eocene
Translation Gocht, 1969: Geological Survey of Canada
Original diagnosis: Davey and Williams, 1966, p. 34
A variety of H. ramosa (Ehrenberg) with smooth, thin-walled central body bearing gonal and sutural processes. Processes solid or hollow and relatively long and slender. Crests proximal and extending along all processes often as far as the trifurcation. Gonal processes mainly trifurcate, sutural processes bifurcate, all
but smallest terminating with small trifurcation.
Dimensions: holotype: diameter of central body 35 by 43 Ám, length of processes 17-23 Ám. Range of London Clay specimens; diameter of central body 32-61.5 Ám. Length of processes up to 29 Ám.
Gocht, 1969, p.31,32:
In the Meckelfeld material, this form group is a fairly closed unit which, in spite of a few transitional forms, can usually be readily differentiated from other variants of the ramosa group.
The main body is approximately ovoid. The membrane (with one exception) is thin and fragile; as a result, the specimens are almost always flattened. The very slender processes end in 2-3 spines which are long and thin and, on well preserved specimens, stiff and straightly spread. At the antapex, the process bases usually expand into a broad sail. The field boundaries take the form of either fine lists or- on the majority of the specimens-- thin lines. Occasionally they can hardly be seen. The similarity of such specimens to Achomosphaera species can not be mistaken.
Occurrence: Early Eocene- Middle Oligocene.
Now Spiniferites ramosus ssp. gracilis. Orignally Hystrichosphaera ramosa var. gracilis, subsequently Spirliferites ramosus var. gracilis, thirdly (and now) Spiniferites ramosus ssp. gracilis.
Tax. jr. synonym of Hystrichosphaeridium plicatum Maier, 1959, according to Sarjeant, 1983, who noted that Hystrichosphaera ramosa var. gracilis (as Spiniferites ramosus ssp. gracilis) must be retained, since a taxon does not have priority outside its own rank.
Holotype: Davey and Williams, 1966, pl.1, fig.5; pl.5, fig.6; Bujak et al., 1980, pl.4, figs.1-2
Locus typicus: London Clay, Sheppey, Kent, England
Stratum typicum: Cenomanian-Eocene
Translation Gocht, 1969: Geological Survey of Canada
Original diagnosis: Davey and Williams, 1966, p. 34
A variety of H. ramosa (Ehrenberg) with smooth, thin-walled central body bearing gonal and sutural processes. Processes solid or hollow and relatively long and slender. Crests proximal and extending along all processes often as far as the trifurcation. Gonal processes mainly trifurcate, sutural processes bifurcate, all
but smallest terminating with small trifurcation.
Dimensions: holotype: diameter of central body 35 by 43 Ám, length of processes 17-23 Ám. Range of London Clay specimens; diameter of central body 32-61.5 Ám. Length of processes up to 29 Ám.
Gocht, 1969, p.31,32:
In the Meckelfeld material, this form group is a fairly closed unit which, in spite of a few transitional forms, can usually be readily differentiated from other variants of the ramosa group.
The main body is approximately ovoid. The membrane (with one exception) is thin and fragile; as a result, the specimens are almost always flattened. The very slender processes end in 2-3 spines which are long and thin and, on well preserved specimens, stiff and straightly spread. At the antapex, the process bases usually expand into a broad sail. The field boundaries take the form of either fine lists or- on the majority of the specimens-- thin lines. Occasionally they can hardly be seen. The similarity of such specimens to Achomosphaera species can not be mistaken.
Occurrence: Early Eocene- Middle Oligocene.