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Hystrichosphaerina neuquina
Hystrichosphaerina neuquina Quattrocchio and Volkheimer, 1983; emend. Quattrocchio and Sarjeant, 1992
Holotype: Quattrocchio and Volkheimer, 1983, pl.B, fig.11; pl.G, figs.37-38
Age: Late Jurassic
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Emended description: [Quattrocchio and Sarjeant, 1992, p. 77-78]:
Hystrichosphaerina neuquina Quattrocchio & Volkheimer, 1983, emend.
(Plate 3, Figs. 5-6; Plate 6, fig. 5; Plate 7, fig. 6; Text-fig. 5)
Emended diagnosis. Cyst skolochorate, subsphaerical to oval. Phragma two layered. Periphragm coarsely and irregularly granulate, forming the processes. Process groups penitabular, cylindrical to trumpet-shaped, 17 in number, the processes in the groups being sometimes interconnected at their bases by crests. Processes in clusters are united by cross-connecting threads or by a broader fusion close to, or at, their distal extremities; however, they are without a distal ring-trabecula. Faint parasutural lines are present between process bases, especially on the operculum. Cingular processes slender, bifurcate and not interconnected distally; sulcal processes lacking. Length of all processes about 1/5 of breadth of central body. Paratabulation : ?4', 6", 6c, 5', 1 p, 1"", Archaeopyle apical, Type tA; operculum free.
Holotype. 1459b: 39/95,2 (illustrated by Quattrocchio & Volkheimer, 1983, plate B figs. 11-12 and plate 5 figs. 37-40).
llustrated specimens. 2965/6A: 11,7/105,4 (Plate 3, Fig. 5; Text-fig. 5); 2965/6B: 9,7/130 X (Plate 3, Fig. 6); 2966/4: 12,5/105,6 (Plate 6, Fig. 5): SEM from horizon 2971 (Plate 7, Fig. 6).
Dimensions. Specimen 2965/6A: length 66 μm, breadth 54 μm length of processes 10-15 μm, central body length 56 μm, breadth 37 μm. Specimen 2965/6B (in antapical view): overall breadth 72 μm, central body breadth 40 μm, length of processes 10-15 μm. Range: overall length (with operculum), 60-72 μm; (without operculum), 34-50 μm. Central body length (without operculum), 47 μm; (with operculum), 50-60 μm. Length of processes, 9-16 μm; proximal width of clusters, 9-14 μm (50 specimens measured).
Remarks. Amphorula delicata van Helden (1986) is quite similar to Hystrichosphaerina neuquina, but its penitabular process clusters open to-
wards the paracingulum and are proportionately broader. Nevertheless, a close evolutionary relationsip seems probable between these two
genera and species. Hystrichosphaerina turonica Alberti 1961, though stratigraphically much later, is close in morphology to H. neuquina but consistently has a ring-trabecula uniting the process tips; moreover, its dimensions are bigger (overall diameter 86-103 μm; body diameter, 58-71 μm; length of the processes, 16-19 μm).
Holotype: Quattrocchio and Volkheimer, 1983, pl.B, fig.11; pl.G, figs.37-38
Age: Late Jurassic
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Emended description: [Quattrocchio and Sarjeant, 1992, p. 77-78]:
Hystrichosphaerina neuquina Quattrocchio & Volkheimer, 1983, emend.
(Plate 3, Figs. 5-6; Plate 6, fig. 5; Plate 7, fig. 6; Text-fig. 5)
Emended diagnosis. Cyst skolochorate, subsphaerical to oval. Phragma two layered. Periphragm coarsely and irregularly granulate, forming the processes. Process groups penitabular, cylindrical to trumpet-shaped, 17 in number, the processes in the groups being sometimes interconnected at their bases by crests. Processes in clusters are united by cross-connecting threads or by a broader fusion close to, or at, their distal extremities; however, they are without a distal ring-trabecula. Faint parasutural lines are present between process bases, especially on the operculum. Cingular processes slender, bifurcate and not interconnected distally; sulcal processes lacking. Length of all processes about 1/5 of breadth of central body. Paratabulation : ?4', 6", 6c, 5', 1 p, 1"", Archaeopyle apical, Type tA; operculum free.
Holotype. 1459b: 39/95,2 (illustrated by Quattrocchio & Volkheimer, 1983, plate B figs. 11-12 and plate 5 figs. 37-40).
llustrated specimens. 2965/6A: 11,7/105,4 (Plate 3, Fig. 5; Text-fig. 5); 2965/6B: 9,7/130 X (Plate 3, Fig. 6); 2966/4: 12,5/105,6 (Plate 6, Fig. 5): SEM from horizon 2971 (Plate 7, Fig. 6).
Dimensions. Specimen 2965/6A: length 66 μm, breadth 54 μm length of processes 10-15 μm, central body length 56 μm, breadth 37 μm. Specimen 2965/6B (in antapical view): overall breadth 72 μm, central body breadth 40 μm, length of processes 10-15 μm. Range: overall length (with operculum), 60-72 μm; (without operculum), 34-50 μm. Central body length (without operculum), 47 μm; (with operculum), 50-60 μm. Length of processes, 9-16 μm; proximal width of clusters, 9-14 μm (50 specimens measured).
Remarks. Amphorula delicata van Helden (1986) is quite similar to Hystrichosphaerina neuquina, but its penitabular process clusters open to-
wards the paracingulum and are proportionately broader. Nevertheless, a close evolutionary relationsip seems probable between these two
genera and species. Hystrichosphaerina turonica Alberti 1961, though stratigraphically much later, is close in morphology to H. neuquina but consistently has a ring-trabecula uniting the process tips; moreover, its dimensions are bigger (overall diameter 86-103 μm; body diameter, 58-71 μm; length of the processes, 16-19 μm).