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Schematophora speciosa
Schematophora speciosa Deflandre and Cookson, 1955, p.262–263, pl.6, figs.11–13; pl.7, fig.11. Emendation: Stover, 1975, p.39.
Holotype: Deflandre and Cookson, 1955, pl.6, fig.11-12
Paratypes: Deflandre and Cookson, 1955
Locus Typicus: Birregurra Bore NO. 1, Victoria, Australia
Stratum typicum: Eocene-Miocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Schematophora speciosa Deflandre and Cookson, 1955, emend. Stover, 1975. According to Stover (1975, p.39), Schematophora speciosa has peritabular ridges, 4-6 µm high and 1.5-2 µm wide, which in side view are irregularly perforate with smooth or slightly fimbriate margins. Inferred tabulation from ridges is 4', 6", 0c, 5"’, 1p, 1"”, 1-3s. Most precingular and postcingular ridges outline more or less rectangular areas except for those adjacent to the sulcus which tend to be more rounded to triangular. Ridges on 6" and as consistently incomplete. Complete specimens are 54-66 µm long and 50-57 µm wide.
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Deflandre and Cookson 1955, p. 262
Diagnosis: Shell ellipsoidal or ovoidal, wing-like ridges with an entire, or more often slightly crenulate, margin, sometimes showing small, clearly defined, vertically placed capitate processes. Bases of ridges irregularly thickened forming small knobs or meshes raised above the more or less clearly marked sculpture of the shell membrane. Any breaks in incomplete shells follow the outlines of the fields, and demonstrate the existence of weaker lines, sometimes distinctly visible, in the spaces between them. Ridges delimiting the fields sometimes joined by short, transverse bars, especially in the region of the small fields. Fields probably about 16 or 17, amongst which 7-9 are larger and 4-5 are small. The small fields are situated in a depressed region which may be considered as the ventral portion. The arrangement of certain of the large quadrangular fields gives the appearance of an incomplete transverse furrow.
Dimensions: Holotype 54 by 52 µm; range 54-61 by 46-54 µm.
Emendation: Stover, L.E., 1975, p.39-40
Revised description (annotated): Cyst ellipsoidal, apical-antapical axis longer than equatorial axis. Wall apparently composed of two appressed layers; endophragm thin (<0.5 µm), untextured; periphragm 1.5-2 µm thick, and unevenly but similarly textures throughout. Projecting from the periphragm are peritabular ridges, 4-6 µm high, 1.5-2 µm wide, which in side view are irregularly perforate with smooth or faintly fimbriate distal margins. Inferred thecal tabulation gonyaulacacean; paratabulation, indicated by (in)complete peritabular ridges: 4', 6'', 0c, 5''', 1p, 1'''', 1-3(?)s. Archaeopyle apical, type A, operculum free, releasd as a single piece. 1' and 4' much smaller than 2' and 3'. Most precingular and postcingular peritabular ridges outline more or less rectangular areas with rounded corners except for those adjacent to the sulcus. Peritabular ridges on 1'', 2''' and 1p tend to delineate roundly triangular to nearly circular areas, smaller than those on the other precingulars and postcingulars. Cingulars not expressed. First postcingular indicated only occasionally by small outgrowth. Area outlined by antapical peritabular ridge roundly heartshaped, with unequal ventral lobes; right lobe narrower than left and pointed toward 6'''. Peritabular ridges on dorsal, lateral and antapical areas almost always complete. Ridges on 6''and anterior sulcals consistently incomplete, ridge on 6'' greatly rediced or absent. Ridges on 1'' and 5'' sometimes incomplete at sulcal side. Especially in sulcal area, segments of peritabular ridges may be shared. Also the ridges of pairs 1'/4' and 2'/3' generally have common medial segments. Medial sulcal area defined by slightly sinuous to nearly straight ridge extending between 2''' and 6''', and by U-shaped ridge between 1p and 6'''. A short ridge may span the antapical part of the U-shaped ridge, thereby delineating small crescent-shaped t semi- circular area, possibly representing a posterior sulcal plate. Other short, discontinuous ridges occur within sulcal area, but their distribution, continuity, and shape appear to be inconsistent. Longitudinal ridges present om dorsal surface between precingular and postcingular peritabular ridges on some specimens.
Dimensions: complete specimens 54-66 µm long and 50-57 µm wide. Specimens without operculum mostly 62-65 µm wide.
Variability: Except for differences in size and in the configuration of ridges in the sulcal area, specimens of Schematophora speciosa display little intraspecific variability.
Affinities:
Stover 1975, p. 40
The species most similar to S. speciosa is Hemiplacophora semilunifera Cookson & Eisenack 1965. Both are of similar size and often occur together. H. semilunifera differs by having only incomplete peritabular ridges. Those in the precingular series occur near the apical plate-margins, those in the postcingular series occur in the antapical plate-margins. On the operculum, ridges are lacking in the central area.
Stover 1975, p. 41
Superficially, S. speciosa resembles Eisenackia ornata. The latter differs in the following respects:
1. cingular series is represented by peritabular ridges that are absent in S. speciosa
2. all peritabular ridges on E.ornata are separated consistently, those on the operculum an ventral surface of S. speciosa tend to merge
3. distances between ridges are less on E. ornata
4. average size of E. ornata specimens is larger, although range sizes overlap
Holotype: Deflandre and Cookson, 1955, pl.6, fig.11-12
Paratypes: Deflandre and Cookson, 1955
Locus Typicus: Birregurra Bore NO. 1, Victoria, Australia
Stratum typicum: Eocene-Miocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Schematophora speciosa Deflandre and Cookson, 1955, emend. Stover, 1975. According to Stover (1975, p.39), Schematophora speciosa has peritabular ridges, 4-6 µm high and 1.5-2 µm wide, which in side view are irregularly perforate with smooth or slightly fimbriate margins. Inferred tabulation from ridges is 4', 6", 0c, 5"’, 1p, 1"”, 1-3s. Most precingular and postcingular ridges outline more or less rectangular areas except for those adjacent to the sulcus which tend to be more rounded to triangular. Ridges on 6" and as consistently incomplete. Complete specimens are 54-66 µm long and 50-57 µm wide.
--------------------------------------------------
Deflandre and Cookson 1955, p. 262
Diagnosis: Shell ellipsoidal or ovoidal, wing-like ridges with an entire, or more often slightly crenulate, margin, sometimes showing small, clearly defined, vertically placed capitate processes. Bases of ridges irregularly thickened forming small knobs or meshes raised above the more or less clearly marked sculpture of the shell membrane. Any breaks in incomplete shells follow the outlines of the fields, and demonstrate the existence of weaker lines, sometimes distinctly visible, in the spaces between them. Ridges delimiting the fields sometimes joined by short, transverse bars, especially in the region of the small fields. Fields probably about 16 or 17, amongst which 7-9 are larger and 4-5 are small. The small fields are situated in a depressed region which may be considered as the ventral portion. The arrangement of certain of the large quadrangular fields gives the appearance of an incomplete transverse furrow.
Dimensions: Holotype 54 by 52 µm; range 54-61 by 46-54 µm.
Emendation: Stover, L.E., 1975, p.39-40
Revised description (annotated): Cyst ellipsoidal, apical-antapical axis longer than equatorial axis. Wall apparently composed of two appressed layers; endophragm thin (<0.5 µm), untextured; periphragm 1.5-2 µm thick, and unevenly but similarly textures throughout. Projecting from the periphragm are peritabular ridges, 4-6 µm high, 1.5-2 µm wide, which in side view are irregularly perforate with smooth or faintly fimbriate distal margins. Inferred thecal tabulation gonyaulacacean; paratabulation, indicated by (in)complete peritabular ridges: 4', 6'', 0c, 5''', 1p, 1'''', 1-3(?)s. Archaeopyle apical, type A, operculum free, releasd as a single piece. 1' and 4' much smaller than 2' and 3'. Most precingular and postcingular peritabular ridges outline more or less rectangular areas with rounded corners except for those adjacent to the sulcus. Peritabular ridges on 1'', 2''' and 1p tend to delineate roundly triangular to nearly circular areas, smaller than those on the other precingulars and postcingulars. Cingulars not expressed. First postcingular indicated only occasionally by small outgrowth. Area outlined by antapical peritabular ridge roundly heartshaped, with unequal ventral lobes; right lobe narrower than left and pointed toward 6'''. Peritabular ridges on dorsal, lateral and antapical areas almost always complete. Ridges on 6''and anterior sulcals consistently incomplete, ridge on 6'' greatly rediced or absent. Ridges on 1'' and 5'' sometimes incomplete at sulcal side. Especially in sulcal area, segments of peritabular ridges may be shared. Also the ridges of pairs 1'/4' and 2'/3' generally have common medial segments. Medial sulcal area defined by slightly sinuous to nearly straight ridge extending between 2''' and 6''', and by U-shaped ridge between 1p and 6'''. A short ridge may span the antapical part of the U-shaped ridge, thereby delineating small crescent-shaped t semi- circular area, possibly representing a posterior sulcal plate. Other short, discontinuous ridges occur within sulcal area, but their distribution, continuity, and shape appear to be inconsistent. Longitudinal ridges present om dorsal surface between precingular and postcingular peritabular ridges on some specimens.
Dimensions: complete specimens 54-66 µm long and 50-57 µm wide. Specimens without operculum mostly 62-65 µm wide.
Variability: Except for differences in size and in the configuration of ridges in the sulcal area, specimens of Schematophora speciosa display little intraspecific variability.
Affinities:
Stover 1975, p. 40
The species most similar to S. speciosa is Hemiplacophora semilunifera Cookson & Eisenack 1965. Both are of similar size and often occur together. H. semilunifera differs by having only incomplete peritabular ridges. Those in the precingular series occur near the apical plate-margins, those in the postcingular series occur in the antapical plate-margins. On the operculum, ridges are lacking in the central area.
Stover 1975, p. 41
Superficially, S. speciosa resembles Eisenackia ornata. The latter differs in the following respects:
1. cingular series is represented by peritabular ridges that are absent in S. speciosa
2. all peritabular ridges on E.ornata are separated consistently, those on the operculum an ventral surface of S. speciosa tend to merge
3. distances between ridges are less on E. ornata
4. average size of E. ornata specimens is larger, although range sizes overlap