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Eatonicysta furensis
Eatonicysta furensis (Heilmann-Clausen and Costa, 1990) Stover and Williams, 1995
Originally Eatonicysta ursulae subsp. furensis, subsequently (and now) Eatonicysta furensis.
Holotype: Heilmann-Clausen 1982, fig. 3A; Heilmann-Clausen & Costa 1989: Pl. 11, fig. 7 Heilmann-Clausen 1993, pl.1 , fig. 7.
Locus typicus: Knuden Cliff, loc. B in Heilmann-Clausen (1982), island Fur. Denmark.
Stratum typicum: Knudshoved Member, 3 m above base, Lower Eocene (Ypresian ).
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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.
Eatonicysta furensis (Heilmann-Clausen in Heilmann-Clausen and Costa, 1989) Stover and Williams, 1995, has about 13 processes, 5 or 6 on the epicyst, and about 7 on the hypocyst. Processes intratabular, one per plate. Individual processes hollow, funnel-shaped, flared distally into a perforate membranous ectophragmal network, whose outline mirrors that of the paraplate. The outlines may be indented or regular. Individual ectophragmal paraplates are connected by a few, usually unbranched trabeculae. Process stems short, generally broad, fibroid, more or less equal in length. Process formula ?4', 6", 0c, 5"’, 1p, 1"”. Eatonicysta furensis differs from E.sequestra in having shorter, broader processes, whose ectophragmal expansions more faithfully mirror the outline of the underlying paraplates and in not having cingular processes. E.ursulae has longer, solid processes, distally united by a complete ectophragm. Size: Holotype, central body width 43 µm, length, no operculum 40 µm, overall width 60 µm, overall length 62 µm, processes generally less than 15 µm.
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Diagnosis: Heilmann-Clausen and Costa 1989, p. 466: Eatonicysta ursulae subsp. furensis
This subspecies differs from E. ursulae subsp. ursulae in the morphology of processes and ectophragm. The processes in subsp. furensis are shorter and funnelshaped. Process stems and ectophragmal network grade imperceptibly into each other. The ectophragmal network is divided into separate areas with tightly interwoven trabeculae, each area corresponding to a process and representing an ectophragmal paraplate. A small number of trabeculae connect individual ectophragmal paraplates.
Dimensions of holotype: Ectocyst length: 62Ám; Ectocyst width: 60Ám; Central body length: 40Ám; Central body width: 43Ám
Remarks: Subspecies furensis is the earliest representative of E. ursulae. Intermediate forms between subsp. furensis and typical subsp. ursulae occur in Denmark at the top of the Knudshoved member. These forms have long and massive processes, like in subsp. ursulae. The ectophragmal network is more homogeneous than in typical subsp. furensis, but pandasutural areas of the network may still be discriminated. The gradual development of subsp. ursulae from subsp. furensis is described in Heilmann-Clausen (in prep.).
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Description: Stover and Williams 1995, p. 104-105: Eatonicysta furensis
Shape. Cyst holocavate with subspherical central body.
Wall relationships: Autophragm complete, ectophragm incomplete and separated from autophragm by processes.
Wallfeatures: Autophragm, excluding archeopyle, appears to bear up to about 13 processes, five or six on the epicyst and about seven on the hypocyst. Processes intratabular, one per paraplate. Individual processes are hollow, funnel-shaped, flared distally into a perforate, membranous, ectophragmal network, whose outline mir-rors that of the paraplate. The outlines may be indented or regular. Individual ectophragmal paraplates are connected by a few, usually unbranched trabeculae. Process stems short, generally broad, fiboid, more or less equal in length.
Excystment mode: Archeopyle apical; appears to be tetratabular, simple and free.
Paratabulation: Sexiform gonyaulacoid, indicated by archeopyle sutures and by intratabular processes. Apparent process formula: ?4', 6", 0c, 5"', lp, 1"".
Paracingulum: Indicated by absence of processes.
Parasulcus: Indicated by absence of processes.
Size: Medium; measurements of holotype: central body width 43 Ám, central body length (no operculum) 40 Ám, overall width 60 Ám, overall length (no operculum) 62 Ám, processes generally less than l5 Ám in length.
Comparison: Stover and Williams 1995, p. 104-105
Eatonicysta furensis differs from Eatonicysta sequestra in having shorter, broader processes, whose ectophragmal expansions more faithfully mirror the outline of the underlying paraplates and in not having paracingular processes. Eatonicysta ursulae always has longer, solid processes, distally united by a complete ectophragm.
Comments: Stover and Williams 1995, p. 104-105
Heilmann-Clausen and Costa (1990) differentiated Eatonicysta ursulae subsp. furensis from the autonym Eatonicysta ursulae subsp. ursulae on the basis of process and ectophragmal development. Further, they considered Eafonicysta ursulae subsp.furensis to be the earliest representative of Eatonicysta ursulae. Heilmann-Clausen (1993) conclusively demonstrated this relationship. We consider the morphology of the two taxa sufficiently distinctive to warrent elevation of Eatonicysta ursulae subs p.furensis to species rank as Eatonicysta furensis.
Stratigraphic and geographic data: Stover and Williams 1995, p. 104-105
Early Eocene (early Ypresian), North Sea Basin, Denmark and Germany; Dinoflagellate Zone D7a of Costa and Manum (1988) in the Wursterheide well, 90 km WNW of Hamburg, Germany.
Originally Eatonicysta ursulae subsp. furensis, subsequently (and now) Eatonicysta furensis.
Holotype: Heilmann-Clausen 1982, fig. 3A; Heilmann-Clausen & Costa 1989: Pl. 11, fig. 7 Heilmann-Clausen 1993, pl.1 , fig. 7.
Locus typicus: Knuden Cliff, loc. B in Heilmann-Clausen (1982), island Fur. Denmark.
Stratum typicum: Knudshoved Member, 3 m above base, Lower Eocene (Ypresian ).
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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.
Eatonicysta furensis (Heilmann-Clausen in Heilmann-Clausen and Costa, 1989) Stover and Williams, 1995, has about 13 processes, 5 or 6 on the epicyst, and about 7 on the hypocyst. Processes intratabular, one per plate. Individual processes hollow, funnel-shaped, flared distally into a perforate membranous ectophragmal network, whose outline mirrors that of the paraplate. The outlines may be indented or regular. Individual ectophragmal paraplates are connected by a few, usually unbranched trabeculae. Process stems short, generally broad, fibroid, more or less equal in length. Process formula ?4', 6", 0c, 5"’, 1p, 1"”. Eatonicysta furensis differs from E.sequestra in having shorter, broader processes, whose ectophragmal expansions more faithfully mirror the outline of the underlying paraplates and in not having cingular processes. E.ursulae has longer, solid processes, distally united by a complete ectophragm. Size: Holotype, central body width 43 µm, length, no operculum 40 µm, overall width 60 µm, overall length 62 µm, processes generally less than 15 µm.
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Diagnosis: Heilmann-Clausen and Costa 1989, p. 466: Eatonicysta ursulae subsp. furensis
This subspecies differs from E. ursulae subsp. ursulae in the morphology of processes and ectophragm. The processes in subsp. furensis are shorter and funnelshaped. Process stems and ectophragmal network grade imperceptibly into each other. The ectophragmal network is divided into separate areas with tightly interwoven trabeculae, each area corresponding to a process and representing an ectophragmal paraplate. A small number of trabeculae connect individual ectophragmal paraplates.
Dimensions of holotype: Ectocyst length: 62Ám; Ectocyst width: 60Ám; Central body length: 40Ám; Central body width: 43Ám
Remarks: Subspecies furensis is the earliest representative of E. ursulae. Intermediate forms between subsp. furensis and typical subsp. ursulae occur in Denmark at the top of the Knudshoved member. These forms have long and massive processes, like in subsp. ursulae. The ectophragmal network is more homogeneous than in typical subsp. furensis, but pandasutural areas of the network may still be discriminated. The gradual development of subsp. ursulae from subsp. furensis is described in Heilmann-Clausen (in prep.).
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Description: Stover and Williams 1995, p. 104-105: Eatonicysta furensis
Shape. Cyst holocavate with subspherical central body.
Wall relationships: Autophragm complete, ectophragm incomplete and separated from autophragm by processes.
Wallfeatures: Autophragm, excluding archeopyle, appears to bear up to about 13 processes, five or six on the epicyst and about seven on the hypocyst. Processes intratabular, one per paraplate. Individual processes are hollow, funnel-shaped, flared distally into a perforate, membranous, ectophragmal network, whose outline mir-rors that of the paraplate. The outlines may be indented or regular. Individual ectophragmal paraplates are connected by a few, usually unbranched trabeculae. Process stems short, generally broad, fiboid, more or less equal in length.
Excystment mode: Archeopyle apical; appears to be tetratabular, simple and free.
Paratabulation: Sexiform gonyaulacoid, indicated by archeopyle sutures and by intratabular processes. Apparent process formula: ?4', 6", 0c, 5"', lp, 1"".
Paracingulum: Indicated by absence of processes.
Parasulcus: Indicated by absence of processes.
Size: Medium; measurements of holotype: central body width 43 Ám, central body length (no operculum) 40 Ám, overall width 60 Ám, overall length (no operculum) 62 Ám, processes generally less than l5 Ám in length.
Comparison: Stover and Williams 1995, p. 104-105
Eatonicysta furensis differs from Eatonicysta sequestra in having shorter, broader processes, whose ectophragmal expansions more faithfully mirror the outline of the underlying paraplates and in not having paracingular processes. Eatonicysta ursulae always has longer, solid processes, distally united by a complete ectophragm.
Comments: Stover and Williams 1995, p. 104-105
Heilmann-Clausen and Costa (1990) differentiated Eatonicysta ursulae subsp. furensis from the autonym Eatonicysta ursulae subsp. ursulae on the basis of process and ectophragmal development. Further, they considered Eafonicysta ursulae subsp.furensis to be the earliest representative of Eatonicysta ursulae. Heilmann-Clausen (1993) conclusively demonstrated this relationship. We consider the morphology of the two taxa sufficiently distinctive to warrent elevation of Eatonicysta ursulae subs p.furensis to species rank as Eatonicysta furensis.
Stratigraphic and geographic data: Stover and Williams 1995, p. 104-105
Early Eocene (early Ypresian), North Sea Basin, Denmark and Germany; Dinoflagellate Zone D7a of Costa and Manum (1988) in the Wursterheide well, 90 km WNW of Hamburg, Germany.