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Hystrichokolpoma cinctum ssp. turgidum
Hystrichokolpoma cinctum ssp. turgidum (Williams and Downie, 1966) Lentin and Williams, 1985
Originally Hystrichokolpoma eisenackii var. turgidum, subsequently Hystrichokolpoma eisenackii ssp. turgidum, thirdly Hystrichokolpoma bulbosum ssp. turgzdum, fourthly (and now) Hystrichokolpoma cinctum ssp. turgidum.
Lentin and Williams, 1981, inadvertently placed this subspecies under Hystrichokolpoma bulbosum (Ehrenberg, 1838) Morgenroth, 1968, when they attempted this new combination.
Holotype: Williams and Downie, 1966, pl.17, fig.5
Locus typicus: London Clay, Enborne, England
Stratum typicum: Early Eocene
Original diagnosis: Williams and Downie, 1966, p. 178-179: Hystrichokolpoma eisenacki ssp. turgidum
Central body ovoidal slightly granular, bearing processes of two types, broad sub-conical or bulbose, with wide or restricted distal opening and slender, simple or bifurcate processes open or closed distally.
Dimensions: Holotype: diameter of central body 40-41 Ám. Length of broad processes up to 21 Ám. Length of slender processes up to 24 Ám. Range of dimensions observed: diameter of central body 44-56 Ám. Length of broad processes 20-30 Ám, width of broad processes 8-26 Ám. Length of slender processes 16-28 Ám, width of slender processes usually 1-3 Ám.
Original description: Williams and Downie, 1966, p. 179
The broad processes of H. eisenacki var. turgidum may be subconical and widely open distally or bulbose with a restricted opening that has a serrate, commonly recurved, margin. Branching similar to that in H. eisenacki can occur, but there are rarely more than one or two branches. The longer tapering antapical process sometimes has very small tubules arising laterally and appears minutely open distally. The broad processes give rise to a characteristic trapezoid outline where they join the central body. The slender equatorial processes are variable in number, generally being restricted to two per plate, with infrequently three occurring. They are open with a digitate or serrate distal margin or they are bifurcate. Often they arise in pairs, being united proximally for as much as 1/3 of their length. The tabulation is as in H. eisenacki with a reduced sixth precingular plate and a large anterior sulcal plate.
Affinities:
Williams and Downie, 1966, p. 179: H. eisenacki var. turgidum differs from H. cinctum in the number of cingular processes and the presence of a large anterior sulcal plate and process, and from the typical form of H. eisenacki in the usual presence of broad processes that have three or four branches distally.
Originally Hystrichokolpoma eisenackii var. turgidum, subsequently Hystrichokolpoma eisenackii ssp. turgidum, thirdly Hystrichokolpoma bulbosum ssp. turgzdum, fourthly (and now) Hystrichokolpoma cinctum ssp. turgidum.
Lentin and Williams, 1981, inadvertently placed this subspecies under Hystrichokolpoma bulbosum (Ehrenberg, 1838) Morgenroth, 1968, when they attempted this new combination.
Holotype: Williams and Downie, 1966, pl.17, fig.5
Locus typicus: London Clay, Enborne, England
Stratum typicum: Early Eocene
Original diagnosis: Williams and Downie, 1966, p. 178-179: Hystrichokolpoma eisenacki ssp. turgidum
Central body ovoidal slightly granular, bearing processes of two types, broad sub-conical or bulbose, with wide or restricted distal opening and slender, simple or bifurcate processes open or closed distally.
Dimensions: Holotype: diameter of central body 40-41 Ám. Length of broad processes up to 21 Ám. Length of slender processes up to 24 Ám. Range of dimensions observed: diameter of central body 44-56 Ám. Length of broad processes 20-30 Ám, width of broad processes 8-26 Ám. Length of slender processes 16-28 Ám, width of slender processes usually 1-3 Ám.
Original description: Williams and Downie, 1966, p. 179
The broad processes of H. eisenacki var. turgidum may be subconical and widely open distally or bulbose with a restricted opening that has a serrate, commonly recurved, margin. Branching similar to that in H. eisenacki can occur, but there are rarely more than one or two branches. The longer tapering antapical process sometimes has very small tubules arising laterally and appears minutely open distally. The broad processes give rise to a characteristic trapezoid outline where they join the central body. The slender equatorial processes are variable in number, generally being restricted to two per plate, with infrequently three occurring. They are open with a digitate or serrate distal margin or they are bifurcate. Often they arise in pairs, being united proximally for as much as 1/3 of their length. The tabulation is as in H. eisenacki with a reduced sixth precingular plate and a large anterior sulcal plate.
Affinities:
Williams and Downie, 1966, p. 179: H. eisenacki var. turgidum differs from H. cinctum in the number of cingular processes and the presence of a large anterior sulcal plate and process, and from the typical form of H. eisenacki in the usual presence of broad processes that have three or four branches distally.