2 Systematic Descriptions
21
Schizosporis balmei (Jansonius 1962) (Fig. 2.2).
Occurrence: Rare, occasionally present in Upper Permian samples of Collie and
Wilga Basins.
Description: Outline circular to sub-circular, smooth. Wall one-layered 2–3 µ
thickness and smooth. Test splitting equatorially. It is significantly larger than
Schizosporis scissus. That fact alone does not justify treating the spore as a separate
species. However, it does not appear in the same stratigraphic horizon as S. scissus.
Dimensions: 65–105 µ in diameter (10 specimens measured).
Remarks and affinity: Schizosporis as the name implies is a spore that splits
upon germination. Spores closely resembling Schizosporus today are those of
Equisetum fluviatile Fig. 2.3a–e, which implies a higher water level, above the
muddy swamp. These spores are excellent indicators of environmental conditions
at the time of deposition. A similar acritarch has been described by Li et al. (2004)
from the Late Permian of South East China.
Genus Peltacystia (Balme and Segroves 1966).
Description: Outline circular to sub-circular. Wall one-layered, sculptured with
concentric ridges and processes. Test splitting equatorially along a zone of
weakness.
Known distribution: Upper Permian of northern Perth Basin, Western Australia,
Lower Permian of Eastern India (Banerjee and D’Rozario 1990), Permian of
Collie Basin (Backhouse 1991).
Discussion: Peltacystia is distinguished from other members of the Schizomorphitae by its unique sculpture of circum-polar ridges which in turn are covered
in flat-topped spines.
Peltacystia like Schizosporis splits equatorially (Fig. 2.4).
Peltacystia venosa (Balme and Segroves 1966) (Fig. 2.4).
Occurrence: Lower Permian to Upper Permian of Collie–Muja Basin, more
frequent in Upper Permian samples than in the Lower Permian.
Description: Entire specimens spheroidal to sub-spheroidal. Usually only circular
to sub-circular halves are found. Wall one-layered and sub-divided into thicker
central area and a thinner marginal zone. Sculpture of outer surface of wall is
complex and consists of concentric thickenings or ridges which support the protrusions of the major sculptural elements. These protrusions extend to about 2 µ
away from the surface. In between the concentric ridges which numbered 1–3,
low-relief ridges or veins are present. The lower ridges are arranged in a polygonal or sub-reticulate pattern. The ruglate-pilate processes project from the corners
of the polygons at fixed intervals. The processes which widen at their bases and
slightly at their tips are a composite of a regulate and pilate sculpture.
Dimensions: 38–70 µ in diameter (15 specimens measured).
Remarks: Algal spores resembling Peltacystia such as species of Pediastrum are
found today in fresh water lakes.
Peltacystia monile (Balme and Segroves 1966) (Fig. 2.5).
Occurrence: Artinskian to upper Permian of Collie–Muja.
21
Schizosporis balmei (Jansonius 1962) (Fig. 2.2).
Occurrence: Rare, occasionally present in Upper Permian samples of Collie and
Wilga Basins.
Description: Outline circular to sub-circular, smooth. Wall one-layered 2–3 µ
thickness and smooth. Test splitting equatorially. It is significantly larger than
Schizosporis scissus. That fact alone does not justify treating the spore as a separate
species. However, it does not appear in the same stratigraphic horizon as S. scissus.
Dimensions: 65–105 µ in diameter (10 specimens measured).
Remarks and affinity: Schizosporis as the name implies is a spore that splits
upon germination. Spores closely resembling Schizosporus today are those of
Equisetum fluviatile Fig. 2.3a–e, which implies a higher water level, above the
muddy swamp. These spores are excellent indicators of environmental conditions
at the time of deposition. A similar acritarch has been described by Li et al. (2004)
from the Late Permian of South East China.
Genus Peltacystia (Balme and Segroves 1966).
Description: Outline circular to sub-circular. Wall one-layered, sculptured with
concentric ridges and processes. Test splitting equatorially along a zone of
weakness.
Known distribution: Upper Permian of northern Perth Basin, Western Australia,
Lower Permian of Eastern India (Banerjee and D’Rozario 1990), Permian of
Collie Basin (Backhouse 1991).
Discussion: Peltacystia is distinguished from other members of the Schizomorphitae by its unique sculpture of circum-polar ridges which in turn are covered
in flat-topped spines.
Peltacystia like Schizosporis splits equatorially (Fig. 2.4).
Peltacystia venosa (Balme and Segroves 1966) (Fig. 2.4).
Occurrence: Lower Permian to Upper Permian of Collie–Muja Basin, more
frequent in Upper Permian samples than in the Lower Permian.
Description: Entire specimens spheroidal to sub-spheroidal. Usually only circular
to sub-circular halves are found. Wall one-layered and sub-divided into thicker
central area and a thinner marginal zone. Sculpture of outer surface of wall is
complex and consists of concentric thickenings or ridges which support the protrusions of the major sculptural elements. These protrusions extend to about 2 µ
away from the surface. In between the concentric ridges which numbered 1–3,
low-relief ridges or veins are present. The lower ridges are arranged in a polygonal or sub-reticulate pattern. The ruglate-pilate processes project from the corners
of the polygons at fixed intervals. The processes which widen at their bases and
slightly at their tips are a composite of a regulate and pilate sculpture.
Dimensions: 38–70 µ in diameter (15 specimens measured).
Remarks: Algal spores resembling Peltacystia such as species of Pediastrum are
found today in fresh water lakes.
Peltacystia monile (Balme and Segroves 1966) (Fig. 2.5).
Occurrence: Artinskian to upper Permian of Collie–Muja.