Palaeocystodinium ventricosum Zevenboom and Santarelli in Zevenboom, 1995, p.161, pl.9, figs.14–15.

Name not validly published: considered a manuscript name.

Holotype: Zevenboom, 1995, pl.9, figs.14–15.
Age: latest early Miocene–middle Miocene.

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Original description (Zevenboom, 1995):
Palaeocystodinium ventricosum Zevenboom and Santarelli sp.nov. (manuscript name) (Plate IX, 12-13).
1979 Palaeocystodinium sp. A, Costa and Downie, plate 3, fig. 11
1986b Palaeocystodinium sp. A ssp B, Powell, plate 2, fig. 6
1989 Palaeocystodinium sp. A, (Costa and Downie, 1979) Manum et al., plate 10, fig. 15
1990 Palaeocystodinium sp. A (costa and Downie, 1979) Daniels et al., plate 10, fig. 4

Manuscript holotype: Sample Cassa 34/1 EF (U44/1) Plate IX, 14, 15
Etymology: Latin, in reference to the shape of the central body, which is like a thick belly.
Type locality: Cassinasco section, Tertiary Piedmont Basin, Italy
Type stratum: Cassinasco Formation

Diagnosis: A species of Palaeocystodinium with a broad subspherical (endo- and pericyst) central body and relatively small apical and antapical periphragmal horns. The periphragmal horns are granulate.

Dimensions: Height of endocyst, 80 (99) 113 µm; Width of endocyst, 28 (38) 50 µm; Height of pericyst, 28 (58) 85 µm. N = 25

Discussion: Palaeocystodinium ventricosum differs from all other Palaeocystodinium spp. Except P. striatogranulosum, Zevenboom and Santarelli sp. nov. in having granules on the apical and antapical horns and in having a round subspherical central body. It differs from P. striatogranulosum, Zevenboom and Santarelli sp. nov. in being smaller and in having a distinct rounded central body.
Occurrences: Rockall Plateau (Coasta and Downie, 1979), Italy (Powell, 1986b and this study), Norwegian Sea (Manum et al., 1989), Germany (Daniels et al., 1990) and The Netherlands (this study).
Total stratigraphic range: Latest Early Miocene through Middle Miocene, see Fig. 5
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