8
1 General Review of Permian Sediments in Western Australia
Microtome Sections
Selected specimens were sectioned following the method developed by Dettmann
as outlined in: Hughes et al. (1962). Sectioning of fossil organic matter remains has
been later updated, modified and applied by the author to ultra-sectioning of organic
remains concentrated from coals and other sediments for observation in transmission
electron microscopy (Glikson 1982; Glikson and Taylor 1986; Glikson 2001; Glikson
2008; Glikson et al. 2011).
1.5.1 Classification
The description of pollen/spores in this book constitutes an attempt to construct a
simplified supra-generic classification for the accommodation of dispersed pollen
and spores within sediments. Various different classifications have been used over
time, with the main ones outlined and discussed by Dettmann (1963). For example,
it is evident when viewing Potonie’s (Potonie and Kremp 1954) and Bharadwaj’s
supra-generic classifications (Bharadwaj 1955, 1958, 1962) that the various groups,
sub-groups and so on become more and more complex with the continual additions
of new supra-generic divisions. The basis for these divisions and sub-divisions is
usually the shape of the tetrad scar and/or exine sculpture. These criteria led to the
splitting of form genera and even species and subsequently their distribution among
different divisions and sub-divisions. Needless to say that this becomes impractical
for correlation purposes which are one of the usages of fossil pollen and spores, and
most impractical when attempting to interpret vegetational and climatic conditions.
It has to be taken into consideration that we are dealing with dispersed spores
and pollen, and consequently lack adequate means for defining a genus in the
sense of recent plant taxonomy. This fact leads to the possibility of fossil dispersed
spores/pollen being grouped under different species of one genus which in fact could
be just variations of one and the same species. This is demonstrated by studies of
spores in situ; for example, a species of the fern Senftenbergia plumosa produced
spores with bacculate projections (Radforth 1939; Remy 1954/6) resembling the
dispersed Permian spore Raistrickia. On the other hand, another species of Senftenbergia, S. pennaeformis produced ‘verrucate’ spores similar to Verrucosisporites
pseudoreticulatus and Campotriletes biornatus. This is an example of two species of
one and the same genus in sporae in situ analogous to three genera and three species
in sporae dispersae.
Smith (1962) in discussing various spores that are isolated and found within one
sporangium emphasises the problem of sporae dispersae as follows: “As sporae
dispersae, Type ‘B’ spores would probably have been placed in the genus Convolutispora Hoffmeister and Staplin (1960). Type ‘A’ spores do not appear to resemble
any previously described spore type. Certainly the two types would have been widely
separated in any classification. Both would most probably have been described under
different names. It is likely that type ‘A’ would have been further split into two or
more species”.
1 General Review of Permian Sediments in Western Australia
Microtome Sections
Selected specimens were sectioned following the method developed by Dettmann
as outlined in: Hughes et al. (1962). Sectioning of fossil organic matter remains has
been later updated, modified and applied by the author to ultra-sectioning of organic
remains concentrated from coals and other sediments for observation in transmission
electron microscopy (Glikson 1982; Glikson and Taylor 1986; Glikson 2001; Glikson
2008; Glikson et al. 2011).
1.5.1 Classification
The description of pollen/spores in this book constitutes an attempt to construct a
simplified supra-generic classification for the accommodation of dispersed pollen
and spores within sediments. Various different classifications have been used over
time, with the main ones outlined and discussed by Dettmann (1963). For example,
it is evident when viewing Potonie’s (Potonie and Kremp 1954) and Bharadwaj’s
supra-generic classifications (Bharadwaj 1955, 1958, 1962) that the various groups,
sub-groups and so on become more and more complex with the continual additions
of new supra-generic divisions. The basis for these divisions and sub-divisions is
usually the shape of the tetrad scar and/or exine sculpture. These criteria led to the
splitting of form genera and even species and subsequently their distribution among
different divisions and sub-divisions. Needless to say that this becomes impractical
for correlation purposes which are one of the usages of fossil pollen and spores, and
most impractical when attempting to interpret vegetational and climatic conditions.
It has to be taken into consideration that we are dealing with dispersed spores
and pollen, and consequently lack adequate means for defining a genus in the
sense of recent plant taxonomy. This fact leads to the possibility of fossil dispersed
spores/pollen being grouped under different species of one genus which in fact could
be just variations of one and the same species. This is demonstrated by studies of
spores in situ; for example, a species of the fern Senftenbergia plumosa produced
spores with bacculate projections (Radforth 1939; Remy 1954/6) resembling the
dispersed Permian spore Raistrickia. On the other hand, another species of Senftenbergia, S. pennaeformis produced ‘verrucate’ spores similar to Verrucosisporites
pseudoreticulatus and Campotriletes biornatus. This is an example of two species of
one and the same genus in sporae in situ analogous to three genera and three species
in sporae dispersae.
Smith (1962) in discussing various spores that are isolated and found within one
sporangium emphasises the problem of sporae dispersae as follows: “As sporae
dispersae, Type ‘B’ spores would probably have been placed in the genus Convolutispora Hoffmeister and Staplin (1960). Type ‘A’ spores do not appear to resemble
any previously described spore type. Certainly the two types would have been widely
separated in any classification. Both would most probably have been described under
different names. It is likely that type ‘A’ would have been further split into two or
more species”.