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Hystrichokolpoma pusillum

Hystrichokolpoma pusillum Biffi and Manum, 1988, p.186,188, pl.5, figs.10-11,13-14,16-17. Holotype: Biffi and Manum, 1988, pl.5, figs.10-11,13; Fauconnier and Masure, 2004, pl.39, figs.6-8. Age: Late Eocene-Late Oligocene.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Hystrichokolpoma pusillum Biffi and Manum, 1988. Diagnosis, from Biffi and Manum (1988, p186), is a subspherical cyst with a granular outer wall. The large intratabular processes are slightly fibrous, inverted, cup-shaped to truncate-pyramidal; cingular and sulcal processes are smaller and more conical, cingular processes larger than the sulcals. Size: cyst length 28-40 µm, width 30-40 µm, length of large processes 6-10 µm, width of same 8-12 µm, length antapical process 8-12 µm, length of slender processes 4-8 µm.
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Original diagnosis: Biffi and manum, 1988, p. 186
Sunspherical cyst with a granular outer wall. The large intratabular processes are slightly fibrous, inverted cup-shaped to truncated-pyramidal; cingular and sulcal processes are smaller and more conical, cingular processes larger than the sulcal ones. Archeopyle apical, type tA; operculum free usually displaced.
Dimensions: holotype: cyst length 30 Ám (38 Ám with operculum); cyst breadth 42 Ám; length of large processes 6-10 Ám; breadth of large processes 6-10 Ám; length of antapical process 10 Ám; length of slender processes 8-9 Ám.
Mean dimensions (10 specimens): cyst length 28(34)40 Ám; cyst breadth 30(36)40 Ám; length of large processes 6(8)10 Ám; breadth of large processes 8(10)12 Ám; length of antapical process 8(10)12 Ám; length of slender processes 4(6)8 Ám.
Description: Biffi and manum, 1988, p. 186, 188Cyst proximochorate, subspherical with a finely granular surface. The large, fibrous intratabular processes are inflated, truncated subpyramidal to inverted cup-shaped, bases generally subpolygonal. The processes appear to be open. The precingular 6'' and the as are almost of equal size; the postcingular 1''' is very small; the six cingulars are represented by subconical to box-like processes with rectangular bases generally larger than the sulcal processes. The latter are more conical, of varying size and shape and it seems possible to recognize the 1p, 1ps, rs and (?) ras. The operculum has four large processes. The formula of paratabulation is: 6', 6'', 6c, 1p, ?5s, 5(?6)''', 1''''; archeopyle apical, type tA, relatively small for Hystrichokolpoma.

Affinities: Bifii and Manum, 1988, p. 188
H. pusillum is characterized by the morphology of its processes; particularly no other species of Hystrichokolpoma has box-like cingular processes.
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