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Impletosphaeridium placacanthum
Impletosphaeridium placacanthum (Deflandre and Cookson, 1955) Morgenroth, 1966; Emendation: May, 1980, p.68, as Systematophora placacantha.
NOW Cleistosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Impletosphaeridium, fourthly Systematophora, fifthly (and now) Cleistosphaeridium.
Taxonomic junior synonyms: Baltisphaeridium (as Cleistosphaeridium) panniforme, according to Sarjeant (1984b, p.86-87); Systematophora (now Cleistosphaeridium) ancyrea, according to Stover and Evitt (1978, p.84) - however, Lentin and Williams (1981, p.272) retained Systematophora ancyrea.
Holotype: Deflandre and Cookson, 1955, pl.9, figs.1-2; Fauconnier and Masure, 2004, pl.76, figs.14-16.
Locus typicus: Victoria, Australia
Stratum typicum: Miocene
Original diagnosis: Deflandre and Cookson 1955, p. 276-277: Hystrichosphaeridium placacanthum
Shell globular, circular or asymmetrical in outline, with a large number of processes that are aligned so as to divide the whole surface into more or less polygonal plate-like areas or fields. Each field is separated from its neighbours by an area devoid of appendages. Processes solid, of variable form, somewhat flexuous, simple or branched with pointed or hammer-shaped extremities, widening at the base. Sometimes the bases of 2 or more processes are connected by bridge-like strands; occasionally the apices may coalesce or be connected by a delicate thread as in Cannosphaeropsis. The fields seem to be of variable size and to have no special equatorial arrangement. The surface of the shell is finely reticulate.
NOW Cleistosphaeridium. Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Impletosphaeridium, fourthly Systematophora, fifthly (and now) Cleistosphaeridium.
Taxonomic junior synonyms: Baltisphaeridium (as Cleistosphaeridium) panniforme, according to Sarjeant (1984b, p.86-87); Systematophora (now Cleistosphaeridium) ancyrea, according to Stover and Evitt (1978, p.84) - however, Lentin and Williams (1981, p.272) retained Systematophora ancyrea.
Holotype: Deflandre and Cookson, 1955, pl.9, figs.1-2; Fauconnier and Masure, 2004, pl.76, figs.14-16.
Locus typicus: Victoria, Australia
Stratum typicum: Miocene
Original diagnosis: Deflandre and Cookson 1955, p. 276-277: Hystrichosphaeridium placacanthum
Shell globular, circular or asymmetrical in outline, with a large number of processes that are aligned so as to divide the whole surface into more or less polygonal plate-like areas or fields. Each field is separated from its neighbours by an area devoid of appendages. Processes solid, of variable form, somewhat flexuous, simple or branched with pointed or hammer-shaped extremities, widening at the base. Sometimes the bases of 2 or more processes are connected by bridge-like strands; occasionally the apices may coalesce or be connected by a delicate thread as in Cannosphaeropsis. The fields seem to be of variable size and to have no special equatorial arrangement. The surface of the shell is finely reticulate.