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Palaeocystodinium pilosum
Palaeocystodinium pilosum Guler et al., 2005, p.421–422, figs.6F–R.
Holotype: Guler et al., 2005, fig.6R.
Age: late? Maastrichtian.
Original description (Guler et al., 2005):
Palaeocystodinium pilosum sp. nov. Figures 6.F-R
Holotype. UNSLP 3425-1 30.5/104.2 England Finder: M30/3; Figs. 6.J-K.
Paratype. UNSLP 3425-2 44/107, England Finder: J44/4; Fig. 6.R.
Type locality. Estancia 25 de Mayo, Cerro Calafate, South of Lago Argentino, Austral Basin.
Type horizon. Sample VG5, 130 m above the base of the section; Maastrichtian (probably late Maastrichtian)
Etymology. From pilosus (Latin): hair, in reference to the periphragm which is densely covered by hair-like projections.
Stratigraphic occurence: Common in samples VG2 and VG5, rare in VG3, VG5, VG6 and VG16.
Diagnosis. Proximate, cornucavate dinoflagellate cysts with an elongate ovoidal central body. Apical and antapical horns are distally acuminate. Periphragm densely covered with fine hairs, endophragm granulate. Intercalary archeopyle, type 2a.
Description:
Fusiform cyst with long, slender, tapering, acuminate apical and antapical horns. Apical horn longer and slightly sharper than the antapical one. Cornucavate, with an elongate ellipsoidal endocyst. Periphragm densely covered with fine, flexuous, hair-like projections which are up to 2 µm long, which become shorter towards the end of the horns. Endopragm finely granulate. No parasutural features. Paratubulation only indicated by an intercalary, steno-deltaform archeopyle, type 2a; operculum generally attached.
Dimensions: Overall length 175 (204) 240 µm. Central body: length 65 (79) 98 µm; width 40 (41) 48 µm. Length of apical horn 65 (75) 85 µm, antapical horn 50 (65) 80 µm (15 specimens measured)
Comparison:
Palaeocystodinim pilosum differs from other previously described species of Palaeocystodinium by having a periphragm completely and densely ornamented with hair-like projections and a granulate endophragm. P. benjaminii Drugg, 1967 is similar in size and shape, and is ornamented with fine hair-like projections but these are restricted to the horn areas. P . bulliforme Ioannides, 1986 is cornucavate to circumcavate, whith a smooth to finely granular periphragm and an endophragm that is smooth and may possess an indentation on the antapical horn. P . hampdenense (Wilson, 1977) Wrenn and Hart, 1988 has a microreticulate periphragm and endophragm and P . granulatum (Wilson, 1967) Lentin and Williams, 1976 presents a densely granulate periphragm and a smooth endophragm.
Remarks: The granulate endophragm was only observed in those few specimens with a free perioperculum.
Holotype: Guler et al., 2005, fig.6R.
Age: late? Maastrichtian.
Original description (Guler et al., 2005):
Palaeocystodinium pilosum sp. nov. Figures 6.F-R
Holotype. UNSLP 3425-1 30.5/104.2 England Finder: M30/3; Figs. 6.J-K.
Paratype. UNSLP 3425-2 44/107, England Finder: J44/4; Fig. 6.R.
Type locality. Estancia 25 de Mayo, Cerro Calafate, South of Lago Argentino, Austral Basin.
Type horizon. Sample VG5, 130 m above the base of the section; Maastrichtian (probably late Maastrichtian)
Etymology. From pilosus (Latin): hair, in reference to the periphragm which is densely covered by hair-like projections.
Stratigraphic occurence: Common in samples VG2 and VG5, rare in VG3, VG5, VG6 and VG16.
Diagnosis. Proximate, cornucavate dinoflagellate cysts with an elongate ovoidal central body. Apical and antapical horns are distally acuminate. Periphragm densely covered with fine hairs, endophragm granulate. Intercalary archeopyle, type 2a.
Description:
Fusiform cyst with long, slender, tapering, acuminate apical and antapical horns. Apical horn longer and slightly sharper than the antapical one. Cornucavate, with an elongate ellipsoidal endocyst. Periphragm densely covered with fine, flexuous, hair-like projections which are up to 2 µm long, which become shorter towards the end of the horns. Endopragm finely granulate. No parasutural features. Paratubulation only indicated by an intercalary, steno-deltaform archeopyle, type 2a; operculum generally attached.
Dimensions: Overall length 175 (204) 240 µm. Central body: length 65 (79) 98 µm; width 40 (41) 48 µm. Length of apical horn 65 (75) 85 µm, antapical horn 50 (65) 80 µm (15 specimens measured)
Comparison:
Palaeocystodinim pilosum differs from other previously described species of Palaeocystodinium by having a periphragm completely and densely ornamented with hair-like projections and a granulate endophragm. P. benjaminii Drugg, 1967 is similar in size and shape, and is ornamented with fine hair-like projections but these are restricted to the horn areas. P . bulliforme Ioannides, 1986 is cornucavate to circumcavate, whith a smooth to finely granular periphragm and an endophragm that is smooth and may possess an indentation on the antapical horn. P . hampdenense (Wilson, 1977) Wrenn and Hart, 1988 has a microreticulate periphragm and endophragm and P . granulatum (Wilson, 1967) Lentin and Williams, 1976 presents a densely granulate periphragm and a smooth endophragm.
Remarks: The granulate endophragm was only observed in those few specimens with a free perioperculum.