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Hystrichokolpoma truncatum

Hystrichokolpoma truncata Biffi and Manum, 1988

Sr. homonym of Hystrichokolpoma truncatum Wilson, 1988.
Holotype: Biffi and Manum, 1988, pl. 6, fig. 7-9
Locus typicus: Bisciaro Fm., Ca' Fusconi section, Marche region, Italy
Stratum typicum: Early Miocene

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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 truncatum Biffi and Manum, 1988. Diagnosis, from Biffi and Manum (1988, p.188), Cyst chorate, subspherical, with punctate surface. Large intratabular processes of box-like shape, tapering distally with commonly entire margin, sometimes slightly branched. Paraplates 6" and as represented by two conical processes almost of equal size. Antapical process broadly cylindrical, distally pointed. Cingular slender processes are subconical, irregularly truncated, probably 2 per plate. H.truncatum differs from H.torquatum in lacking parasutural ridges and accompanying penitabular bands and in the general process style. It differs from H.salacium by the larger processes being “fat” and distally tapering and the smaller ones conical and simple rather than branched. H.poculum has simple large processes but they are cup-shaped and distally open, furthermore the cingular processes are fewer. Size: cyst length 30-40 µm, width 40-44 µm, length of large processes 10-18 µm, width of same 14-20 µm, length of antapical process 22-24 µm, length of slender processes 4-8 µm.
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Original description: Biffi and Manum, 1988, p. 188
Diagnosis: Cyst chorate, subsphaerical, with punctate surface. Large intratabular processes of box-like shape, tapering distally with commonly entire margin, sometimes slightly branched (pl. 6, fig. 5-6). Paraplates 6'' and as represented by two conical processes almost of equal size. Antapical process broadly cylindrical, distally pointed. Cingular slender processes are subconical, irregularly truncated, probably 2 per plate. Archeopyle is apical, type tA; operculum free.
Dimensions: Holotype: cyst length 34 Ám without operculum; cyst breadth 44 Ám; length of large processes 16-20 Ám; length of antapical process 20 Ám; length of slender processes 6-8 Ám.
Mean values (bracketed) and extremes (n = 10): cyst length 30(34)40 Ám; cyst breadth 40(42)44 Ám; length of large processes 10(14)18 Ám; breadth of large processes 14(18)20 Ám; length of antapical process 22(23)24 Ám; length of slender processes 4(6)8 Ám.
Description (annotated): The large intratabular processes are box-like, tapering, with a subpolygonal base; their distal margin is generally entire, but sometimes it appears simply branched; distal ends appear closed. The 6'' paraplate is represented by a slender often conical process, similar in size and shape to the as; also the postcingular 1''' is marked by a reduced subconical process. The
paracingulum is marked by numerous, small subconical truncate to acuminate processes, probably 2 per paraplate. The parasulcal processes (?5) include two large ones, representing the 1p and ps paraplates. The archeopyle is apical, type tA, with a free operculum.

Affinities:
Biffi and Manum, 1988, p. 188
Hystricholokolpoma truncata n. sp. belongs to the Hystrichokopolma plexus with box-like large processes; it differs from H. torquata Damassa (1979) in lacking parasutural ridges and accompanying penitabular bands and in the general process style; from H. salacia Eaton (1976) by large processes being 'fat' and distally tapering and the smaller ones conical and simple rather than branches; H. poculum Maier (1959) emend. Sarjeant (1983) has also simple large processes, but they are cupshaped and distally open; furthermore the cingular processes are fewer.
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