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Enneadocysta pectiniformis
Enneadocysta pectiniformis (Gerlach, 1961) emend. Stover and Williams, 1995
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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.
Enneadocysta pectiniformis (Gerlach, 1961) Stover and Williams, 1995, emend. Stover and Williams, 1995, has 20 processes, 11 on the epicyst, nine on the hypocyst, and none on the cingulum. Process tips generally licrate, some simply branched. Process formula: 4', 6", 0c, 6”’, 2"”, 1as, 1ps. There are 7 processes on the archeopyle margin. Size: body diameter 40-50 µm, overall diameter 65-87 µm, process length 13-24 µm.
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Stover and Williams, 1995, p. 114-115
Plate 6, figures 1a-e, 2a-b, 3a-d, 4a-c; text-figure 1, nos. D, F
- Baltisphaeridium pectiniforme Gerlach 1961, p. 195-196, pl. 28, fig. 14; text-fig. 18
- Cleistosphaeridium pectiniforme (Gerlach 1961) Davey 1966 et al.. p. 170
- Cleistosphaeridium pectiniforme (Gerlach 1961) Davey et al. 1969, p. 16
- Areosphaeridium? pectiniforme (Gerlach 1961) Stover and Evitt 1978, p. 20
- Areosphaeridium pectiniforme (Gerlach 1961) Stover and Evitt 1978, emended Sarjeant 1984, p. 83-86, pl. 1, fig. 2; pl. 4, fig. 2
Emended description:
Shape: Cysts skolochorate with subspherical to nearly subspherical central body.
Wall relationships: Autophragm only.
Wall features: Autophragm smooth or faintly granulate; central body typically with 20 intratabular processes, 11 on epicyst and nine on hypocyst; paracingular processes absent. Process stems solid, smooth and faintly fibroid, generally narrow and expanded distally, usually abruptly; most process tips licrate, others simply or complexly branched. Licrate tips are arcuate, more or less semicircular to horseshoe-shaped, relatively long with smooth inner margins and denticulate to spinulate outer margins. Of the four apical processes, licrate tips larger on the two dorsal processes than on the two ventral ones. However, in each pair of dorsal and ventral apical processes, ends of licrate tips face each other medially. Processes on paraplates 2'' to 5'' have licrate tips with ends directed equatorially; tips of processes on paraplates 6'' and anterior sulcal simply or complexly branched, usually the former, and process tips on 1'' may be branched or licrate. Processes on postcingular paraplates 2''' to 5''' have licrate tips with ends also directed equatorially. Thus, ends of opposed dorsal and lateral intratabular processes face each other. Processes on paraplates 1''' and 6''' similar in size and their tips, like the end of the posterior parasulcal process, are frequently branched or rarely licrate. The two antapical processes tend to have narrow stems and ends of their licrate tips face one another medially.
Excystment tvpe: Archeopyle apical; operculum tetratabular, simple, equidimensional or nearly so and free.
Paratabulation: Indicated on epicyst by principal and accessory archeopyle sutures, when latter developed, and by positions of intratabular processes; on hypocyst by process positions only. Process formula: 4', 6'', 0c, 6''', 2'''', 1as, 1ps. Hypocystal processes arranged in partiform pattern.
Paracingulum: Expressed by absence of processes.
Parasulcus: Limits indicated anteriorly by sulcal notch and anterior parasulcal process, posteriorly by posterior parasulcal process.
Size: Intermediate; measurements of 10 specimens: body diameter 40 Ám (46 Ám) 50 Ám, overall diameter 65 Ám (80 Ám) 87 Ám, process length (25 processes) 13 Ám (20 Ám) 24 Ám. Mean values shown in parentheses.
Comments
The emended description recognizes that:
1) seven processes are located immediately subjacent to the archeopyle margin (pl. 6, figs. Ia-e)
2) there are consistently 11 processes on the epicyst (TextFig. 1, no. F) and nine on the hypocyst (text-fig. 1, no. D)
3) the latter are arranged in the partiform pattern (pl. 6, fig. le)
4) on intratabular processes with licrate tips, the exact orientation of the arcuate structures is predetermined, predictable and consistent. On some specimens of Enneadocysta pectiniformis the process stems are pitted; we consider the pitting as an artifact of preservation or maceration.
On the basis of the numerous specimens examined during this study we found the number of processes to be remarkably consistent (20 on complete specimens, 16 on those lacking opercula) and paracingular processes to be characteristically absent (pl. 6, figs. 3a-d).
These observations do not accord with the paratabulation formula presented by Sarjeant (1984), which accounts for 25 to 30 processes. Nor do we concur with his statement "...that the holotype [of Areosphaeridium pectiniforme] corresponds in all particulars with Eaton's Areosphaeridium multicornutum." Thus, Enneadocysta multicornuta is herein retained as a separate species.
Type locality and stratum: Emsburen Borehole-7, northwest Germany.
Stratum: Lower Oligocene at 179 meters.
Holotype:
Specimen shown in Gerlach (1961, pl. 28, fig. 14 and text-fig. 18 [drawing of a process]); re-illustrated by Sarjeant (1984, pl. 1, fig. 2. and pl. 4, fig. 2).
Stratigraphic and geographic data:
The confirmed range of Enneadocysta pectiniformis is late Mid Eocene (Bartonian) to Early Oligocene (Rupelian); the species possibly ranges into the Late Oligocene (Chattian).
The species is confined to the Northern Hemisphere and has confirmed occurrences in the following European countries: Germany, Belgium France and Italy.
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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.
Enneadocysta pectiniformis (Gerlach, 1961) Stover and Williams, 1995, emend. Stover and Williams, 1995, has 20 processes, 11 on the epicyst, nine on the hypocyst, and none on the cingulum. Process tips generally licrate, some simply branched. Process formula: 4', 6", 0c, 6”’, 2"”, 1as, 1ps. There are 7 processes on the archeopyle margin. Size: body diameter 40-50 µm, overall diameter 65-87 µm, process length 13-24 µm.
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Stover and Williams, 1995, p. 114-115
Plate 6, figures 1a-e, 2a-b, 3a-d, 4a-c; text-figure 1, nos. D, F
- Baltisphaeridium pectiniforme Gerlach 1961, p. 195-196, pl. 28, fig. 14; text-fig. 18
- Cleistosphaeridium pectiniforme (Gerlach 1961) Davey 1966 et al.. p. 170
- Cleistosphaeridium pectiniforme (Gerlach 1961) Davey et al. 1969, p. 16
- Areosphaeridium? pectiniforme (Gerlach 1961) Stover and Evitt 1978, p. 20
- Areosphaeridium pectiniforme (Gerlach 1961) Stover and Evitt 1978, emended Sarjeant 1984, p. 83-86, pl. 1, fig. 2; pl. 4, fig. 2
Emended description:
Shape: Cysts skolochorate with subspherical to nearly subspherical central body.
Wall relationships: Autophragm only.
Wall features: Autophragm smooth or faintly granulate; central body typically with 20 intratabular processes, 11 on epicyst and nine on hypocyst; paracingular processes absent. Process stems solid, smooth and faintly fibroid, generally narrow and expanded distally, usually abruptly; most process tips licrate, others simply or complexly branched. Licrate tips are arcuate, more or less semicircular to horseshoe-shaped, relatively long with smooth inner margins and denticulate to spinulate outer margins. Of the four apical processes, licrate tips larger on the two dorsal processes than on the two ventral ones. However, in each pair of dorsal and ventral apical processes, ends of licrate tips face each other medially. Processes on paraplates 2'' to 5'' have licrate tips with ends directed equatorially; tips of processes on paraplates 6'' and anterior sulcal simply or complexly branched, usually the former, and process tips on 1'' may be branched or licrate. Processes on postcingular paraplates 2''' to 5''' have licrate tips with ends also directed equatorially. Thus, ends of opposed dorsal and lateral intratabular processes face each other. Processes on paraplates 1''' and 6''' similar in size and their tips, like the end of the posterior parasulcal process, are frequently branched or rarely licrate. The two antapical processes tend to have narrow stems and ends of their licrate tips face one another medially.
Excystment tvpe: Archeopyle apical; operculum tetratabular, simple, equidimensional or nearly so and free.
Paratabulation: Indicated on epicyst by principal and accessory archeopyle sutures, when latter developed, and by positions of intratabular processes; on hypocyst by process positions only. Process formula: 4', 6'', 0c, 6''', 2'''', 1as, 1ps. Hypocystal processes arranged in partiform pattern.
Paracingulum: Expressed by absence of processes.
Parasulcus: Limits indicated anteriorly by sulcal notch and anterior parasulcal process, posteriorly by posterior parasulcal process.
Size: Intermediate; measurements of 10 specimens: body diameter 40 Ám (46 Ám) 50 Ám, overall diameter 65 Ám (80 Ám) 87 Ám, process length (25 processes) 13 Ám (20 Ám) 24 Ám. Mean values shown in parentheses.
Comments
The emended description recognizes that:
1) seven processes are located immediately subjacent to the archeopyle margin (pl. 6, figs. Ia-e)
2) there are consistently 11 processes on the epicyst (TextFig. 1, no. F) and nine on the hypocyst (text-fig. 1, no. D)
3) the latter are arranged in the partiform pattern (pl. 6, fig. le)
4) on intratabular processes with licrate tips, the exact orientation of the arcuate structures is predetermined, predictable and consistent. On some specimens of Enneadocysta pectiniformis the process stems are pitted; we consider the pitting as an artifact of preservation or maceration.
On the basis of the numerous specimens examined during this study we found the number of processes to be remarkably consistent (20 on complete specimens, 16 on those lacking opercula) and paracingular processes to be characteristically absent (pl. 6, figs. 3a-d).
These observations do not accord with the paratabulation formula presented by Sarjeant (1984), which accounts for 25 to 30 processes. Nor do we concur with his statement "...that the holotype [of Areosphaeridium pectiniforme] corresponds in all particulars with Eaton's Areosphaeridium multicornutum." Thus, Enneadocysta multicornuta is herein retained as a separate species.
Type locality and stratum: Emsburen Borehole-7, northwest Germany.
Stratum: Lower Oligocene at 179 meters.
Holotype:
Specimen shown in Gerlach (1961, pl. 28, fig. 14 and text-fig. 18 [drawing of a process]); re-illustrated by Sarjeant (1984, pl. 1, fig. 2. and pl. 4, fig. 2).
Stratigraphic and geographic data:
The confirmed range of Enneadocysta pectiniformis is late Mid Eocene (Bartonian) to Early Oligocene (Rupelian); the species possibly ranges into the Late Oligocene (Chattian).
The species is confined to the Northern Hemisphere and has confirmed occurrences in the following European countries: Germany, Belgium France and Italy.
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