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Vozzhennikovia spinula
Vozzhennikovia spinula Stover and Hardenbol, 1994
Holotype: Stover and Hardenbol, 1994, pl.12, fig.80.
Age: Rupelian.
Vozzhennikovia spinula sp. nov.
Plate 12, Figures 80, 81 a-82b
Description: Stover and Hardenbol, 1994, p. 39-40
Proximate peridiniacean, cornucavate cysts with short apical and two antapical horns; right
antapical horn usually reduced. Endophragm thin, smooth, more or less circular in outline,
appressed to periphragm almost everywhere and typically discernible only at the bases of
horns. Periphragm also thin, outline peridinioid, lateral margins gently convex, antapical
margin straight or nearly so. Periphragmal surface ornamented with numerous, but not
densely arranged, spinules and/or coni. Their distribution appears to be nontabular, but
some of the ornamentation may be intratabular or possibly penitabular. Accumulation
bodies usually present within the cysts. Paratabulation indicated by the middorsal
archeopyle, when discernible, and the nearly planar paracingulum. Latter expressed by
two, transverse, parallel low ridges with finely denticulate crests. Operculum commonly in
place, occasionally released entirely or adherent posteriorly. Other indications of
paratabulation absent.
Size: intermediate; length 55 to 61µm, width 53 to 58µm.
Comparison
Vozzhennikovia spinula differs from V. cearaichia (this paper) by being more coarsely
ornamented and by having a better developed paracingulum and a less rounded outline.
Other species of Vozzhennikovia, V. apertura (Wilson 1967) Lentin and Williams 1976,
V. rotunda (Wilson 1967) Lentin and Williams 1976 and V. spinulosa Wilson 1984, are
more densely ornamented than V. spinula.
Types
Holotype : Plate 12, figure 80, Boom Composite Section sample at 7.68 meters.
Paratypes: Plate 12, figures 81 a-b and 82a-b from Boom Composite Section samples at
8.55 and 7.68 meters, respectively. Type specimens are from the Steendorp locality.
Occurrence
Specimens of Vozzhennikovia spinula occur quite consistently in the Belsele-Waas and the
lower part of the Terhagen Members of the Boom Formation between 1.50 and 15.50
meters in the composite section, above which only a single specimen was recorded at the
21.09 meter level. The species is also known from the Ruisbroek Member of the Zelzate
Formation and the Belsele-Waas Member of the Boom Formation in the Doel 14E-194
Well.
Holotype: Stover and Hardenbol, 1994, pl.12, fig.80.
Age: Rupelian.
Vozzhennikovia spinula sp. nov.
Plate 12, Figures 80, 81 a-82b
Description: Stover and Hardenbol, 1994, p. 39-40
Proximate peridiniacean, cornucavate cysts with short apical and two antapical horns; right
antapical horn usually reduced. Endophragm thin, smooth, more or less circular in outline,
appressed to periphragm almost everywhere and typically discernible only at the bases of
horns. Periphragm also thin, outline peridinioid, lateral margins gently convex, antapical
margin straight or nearly so. Periphragmal surface ornamented with numerous, but not
densely arranged, spinules and/or coni. Their distribution appears to be nontabular, but
some of the ornamentation may be intratabular or possibly penitabular. Accumulation
bodies usually present within the cysts. Paratabulation indicated by the middorsal
archeopyle, when discernible, and the nearly planar paracingulum. Latter expressed by
two, transverse, parallel low ridges with finely denticulate crests. Operculum commonly in
place, occasionally released entirely or adherent posteriorly. Other indications of
paratabulation absent.
Size: intermediate; length 55 to 61µm, width 53 to 58µm.
Comparison
Vozzhennikovia spinula differs from V. cearaichia (this paper) by being more coarsely
ornamented and by having a better developed paracingulum and a less rounded outline.
Other species of Vozzhennikovia, V. apertura (Wilson 1967) Lentin and Williams 1976,
V. rotunda (Wilson 1967) Lentin and Williams 1976 and V. spinulosa Wilson 1984, are
more densely ornamented than V. spinula.
Types
Holotype : Plate 12, figure 80, Boom Composite Section sample at 7.68 meters.
Paratypes: Plate 12, figures 81 a-b and 82a-b from Boom Composite Section samples at
8.55 and 7.68 meters, respectively. Type specimens are from the Steendorp locality.
Occurrence
Specimens of Vozzhennikovia spinula occur quite consistently in the Belsele-Waas and the
lower part of the Terhagen Members of the Boom Formation between 1.50 and 15.50
meters in the composite section, above which only a single specimen was recorded at the
21.09 meter level. The species is also known from the Ruisbroek Member of the Zelzate
Formation and the Belsele-Waas Member of the Boom Formation in the Doel 14E-194
Well.