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Systematophora rosenfeldii
Systematophora rosenfeldii Volkheimer and Sarjeant, 1993
Holotype: Volkheimer and Sarjeant, 1993, fig.2, no.1-2, fig.6, no. 3
Paratypes: Volkheimer and Sarjeant, 1993
Locus typicus: Santa Elena, W. Argentina
Stratum typicum: Early Cretaceous
Original diagnosis: Volkheimer and Sarjeant, 1993, p. 251-254
Skolochorate dinoflagellate cysts. Central body subsphaerical. Phragma laevigate to granulate, two layered, the layers being closely appressed; the processes are formed by the periphragm only. Processes of three different types: 1. penitabular to intratabular annulate complexes in the apical, precingular and postcingular series and on the posterior intercalary and antapical paraplates; 2. a cingular series consisting of ten isolate processes; and 3. in the sulcal region, two processes arising from a longitudinal ridge. Paratabulation: 2pr, 4", 6"", 6c, 6""", 1p, 1"""", 2s; process formula 4", 6"", 10c, 6""", 1p, 1"""", 2. The preapicals (pr) are indicated by irregular ridges on the phragma surface; they do not bear processes. Every apical, precingular, postcingular, posterior intercalary and antapical paraplate bears a penitabular to intratabular ring complex. These arise from annular, sometimes arcuate ridges which may be smooth or may give rise to spinelets of variable length. Processes often broad and sometimes fused distally or near mid-height,frequently bifurcate, rarely trifurcate. Exceptionally, processes may be connected distally within a process group, but adjacent groups are never connected. Surfaces of processes smooth. Archaeopyle apical; the operculum normally remains intact, not separating into opercular pieces.
Dimensions: Holotype : maximum overall cross-measurement 86 µm, length of central body 46 µm, breadth 61 µm, length of processes up to 21 µm.
Range of dimensions: maximum overall cross-measurement 62-90 µm, length of central body 32-54 µm in specimens without operculum, breadth 44-68 µm, maximum length of processes 16-21 µm. (50 specimens measured).
Affinities: Volkheimer and Sarjeant, 1993, p. 254:
Systematophora rosenfeldii is similar to S. areolata Klement, 1960, but the latter bears on the cingular zone "six narrow, elongate rectangular fields which alternate with intervals of approximately the same length". These fields bear at each end a process.
Our material does not show basal ridges on the cingular region; most or all cingular processes are isolate, the cingular paraplates being usually represented by two linearly arranged processes.
Systematophora palmula Davey, 1982 has membranous processes in the precingular, postcingular and antapical regions and simple apical, paracingular and parasulcal processes.
Holotype: Volkheimer and Sarjeant, 1993, fig.2, no.1-2, fig.6, no. 3
Paratypes: Volkheimer and Sarjeant, 1993
Locus typicus: Santa Elena, W. Argentina
Stratum typicum: Early Cretaceous
Original diagnosis: Volkheimer and Sarjeant, 1993, p. 251-254
Skolochorate dinoflagellate cysts. Central body subsphaerical. Phragma laevigate to granulate, two layered, the layers being closely appressed; the processes are formed by the periphragm only. Processes of three different types: 1. penitabular to intratabular annulate complexes in the apical, precingular and postcingular series and on the posterior intercalary and antapical paraplates; 2. a cingular series consisting of ten isolate processes; and 3. in the sulcal region, two processes arising from a longitudinal ridge. Paratabulation: 2pr, 4", 6"", 6c, 6""", 1p, 1"""", 2s; process formula 4", 6"", 10c, 6""", 1p, 1"""", 2. The preapicals (pr) are indicated by irregular ridges on the phragma surface; they do not bear processes. Every apical, precingular, postcingular, posterior intercalary and antapical paraplate bears a penitabular to intratabular ring complex. These arise from annular, sometimes arcuate ridges which may be smooth or may give rise to spinelets of variable length. Processes often broad and sometimes fused distally or near mid-height,frequently bifurcate, rarely trifurcate. Exceptionally, processes may be connected distally within a process group, but adjacent groups are never connected. Surfaces of processes smooth. Archaeopyle apical; the operculum normally remains intact, not separating into opercular pieces.
Dimensions: Holotype : maximum overall cross-measurement 86 µm, length of central body 46 µm, breadth 61 µm, length of processes up to 21 µm.
Range of dimensions: maximum overall cross-measurement 62-90 µm, length of central body 32-54 µm in specimens without operculum, breadth 44-68 µm, maximum length of processes 16-21 µm. (50 specimens measured).
Affinities: Volkheimer and Sarjeant, 1993, p. 254:
Systematophora rosenfeldii is similar to S. areolata Klement, 1960, but the latter bears on the cingular zone "six narrow, elongate rectangular fields which alternate with intervals of approximately the same length". These fields bear at each end a process.
Our material does not show basal ridges on the cingular region; most or all cingular processes are isolate, the cingular paraplates being usually represented by two linearly arranged processes.
Systematophora palmula Davey, 1982 has membranous processes in the precingular, postcingular and antapical regions and simple apical, paracingular and parasulcal processes.