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Eatonicysta ursulae
Eatonicysta ursulae (Morgenroth, 1966) Stover and Evitt, 1978; Emendation: Stover and Williams, 1995, p.105-106, as Eatonicysta ursulae
Originally Cannosphaeropsis, subsequently Membranilarnacia, thirdly (and now) Eatonicysta.
Tax. sr. synonym of Membranilarnacia diktyophora Agelopoulos, 1967, according to Eaton, 1976.
Tax. sr. synonym of Membranilarnacia reticulata Williams and Downie, 1966, according to de Coninck, 1969, and Gocht, 1969.
Holotype: Morgenroth, 1966a, pl.3, fig.11; Eisenack and Kjellström, 1972, figure to left - p.143; Fensome et al., 1995, fig.1 - p.1865.
Paratypes: Morgenroth, 1966
Locus typicus: Fehmarn, Katharinenhof, NW Germany
Stratum typicum: Early Eocene
Translation Morgenroth, 1966: LPP
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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 ursulae (Morgenroth, 1966a) Stover and Evitt, 1978, emend. Stover and Williams, 1995. According to Stover and Williams (1995, p.106) this species has 17 processes, 10 on the epicyst and 7 on the hypocyst. Processes are solid, partly fibrous to almost completely fibrous and perforate distally where they join the ectophragm. Mesh of ectophragm usually uniform whereas lumina which tend to be polygonal vary in size and shape. Archeopyle apical with only three processes on some opercula.. Process formula is 3-4', 6", 0-4c, 5"’, 1p, 1"”.
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Original description: Morgenroth 1966, p. 20: Cannosphaeropsis ursulae
Diagnosis: A species in the genus Cannosphaeropsis. Thin-walled central body.
16-18 relatively long, solid processes normaly support an envelope consisting of a fine meshwork.
Description: The thin-walled, spherical central body possess a smooth or at least a weakly reticulate surface. On the surface 16-18 evenly distributed, slender, solid processes are present. These support the concentric envelope, which consist in most of the specimens of a extremely delicate, differentiated meshwork (see text fig.12). The processes split up distally forming a fibrous meshwork, which is indistinct on some specimens. A thickening of the meshwork often results in an almost smooth, closed enveloppe. In almost all specimens an irregular shaped pylome, with a denticulate margin, is present. Splitting results in the development of a cap with 3-4 processes, on which the remains of the torn-off outer network are present.
Dimensions: central body diameter: 45-53 Ám; whole cyst diameter: 92-114 Ám; length processes: 6-25 Ám (measured: 100 specimens).
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For postulated relationships between Eatonicysta ursulae and other species, see Eaton, 1971, and Bujak, 1976.
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Emended description: Stover and Williams 1995, p. 105-106
Shape: Cysts holocavate, autocyst and ectocyst subspherical, shape of ectophragm may be modified by folding.
Wall relationships: Holocavate, autophragm and ectophragm widely separated. ectophragm supported by processes.
Wall features: Autophragm smooth, faintly granular or punctoreticulate; with 17 intratabular processes, 10 on epicyst and seven on hypocyst. Processes solid, partly to almost completely fibroid and somewhat expanded distally where they merge with the ectophragm. Process stems relatively narrow (some slightly wider than others), more or less equal in length. Process length commonly less, but may be equal to, body diameter. Ends of processes generally perforate where they join the ectophragm. Mesh of the ectophragm smooth, narrow and fairly uniform in width whereas the lumina, which tend to be polygonal, vary in size and shape. In general, lumina near processes are smaller than those in intervening
Excystment mode: Archeopyle apical; operculum tetratabular. simple, about equidimensional and free with three or four processes. On opercula with just three processes, a single ventral process presumably represents paraplates 1' and 4'
Paratabulation: Gonyaulacoid, indicated on epicyst by principal and short accessory archeopyle sutures, also by locations of intratabular processes; elsewhere on central body the paratabulation expressed solely by positioning of processes. Process formula: 3-4', 6", 0-4c, 5"', lp, 1"", 0s. First precingular paraplate wider than sixth and process denoting paraplate Ip usually narrower than others. The seven hypocystal processes arranged in standard sexiform pattern.
Paracingulum: Paracingular area lacking processes or may have four processes.
Parasulcus: Parasulcal area without processes; a median parasulcal notch frequently discernible. Presence of sulcal processes not firmly established (see Comments).
Size: Intermediate to large; specimens 85Ám to 135Ám in diameter; autocysts about 40Ám to 55Ám in diameter; processes up to 40Ám in length, most processes between 20Ám and 30Ám.
Comments: Stover and Williams 1995, p. 105-106
The emended descnption indicates that the hypocystal paratabulation is the standard sexiform pattern (text-fig. 1, no. B2), provides additional information about the nature of the ectophragm and modifies the paratabulation formula (text-fig. I, nos. B l-B2). Williams and Downie (1966) recognized two morphotypes of this species, which were informally designated Eatonicysta ursulae Var. a (as Membranilarnacia reticulata Var. a) and Eatonicysta ursulae Var. b (as Membranilarnacia reticulata Var. b). Eatonicysta ursulae Var. a, the commoner of the two, lacked paracingular processes but evidently could have parasulcal processes (although
the occurrence of parasulcal processes has not been confirmed), as opposed to Eatonicysta ursulae Var. b which had four paracingular processes. The presence or absence of parasulcal processes on Eatonicysta ursulae Var. b was not mentioned. Of the numerous specimens of Eatonicysta ursulae available during this study, none were devoid of both paracingular and parasulcal processes.
Stratigraphic and geographic data: Stover and Williams 1995, p. 105-106
The geochronologic range of Eatonicysta ursulae is Early Eocene (Ypresian) to early Mid Eocene (Lutetian). The species does not occur in the earliest Early Eocene. In terms of depositional sequences in the Hampshire Basin, the base of Eatonicysta ursulae lies within the 53 Ma sequence and its top is within the 46.5 Ma sequence. In terms of nannofossil zones, the species ranges from Zone NP 11 to within Zone NP 15, which in turn, correlates with the upper part of planktonic foraminiferal Zone P6B to within Zone P 11. Publications that depict the stratigraphic range of Eatonicysta ursulae are Harker and Sarjeant (1975)--Early to Mid Eocene; these authors also show the species as occurring in the Cenomanian of France (ibid.), but this record has not been confirmed; Williams (1977)--Early [but not earliest] Eocene to early Mid Eocene; Bujak et al. ( 1980)--Early to Mid Eocene, from the base of local palynological Zone LC-2 to the lower part of Zone B-4; Williams and Bujak (1985)--about the middle of the Early Eocene to early Mid Eocene; Powell (1992)--about mid Early Eocene to early Mid Eocene.
Eatonicysta ursulae is confined to the Northern Hemisphere. Confirmed European reports are from England, Germany, Denmark, The Netherlands, Belgium, and Romania. Just two occurrences have been noted outside Europe: offshore eastern Canada, and the eastern North Atlantic. Table S in Costa and Downie (1979) shows the co-occurrence of Eatonicysta ursulae and Apectodinium augustum (Harland 1979) Lentin and Williams 1981 in the Lower Eocene section. In our expenence, the two species are stratigraphically incompatible, with the latter present only in Upper Paleocene strata. In addition, no other definitive record shows Eatonicysta ursulae extending through the Middle Eocene as depicted by Costa and Downie (1979).
Synonym list Stover and Williams 1995, p. 105:
Cannosphaeropsis ursulae MORGENROTH 1966, p.20, pl.3, figs.11 - 12.
Membranilarnacia reticulala WILLIAMS and DOWNIE 1966, p.220-222, pl. 24, figs. 4, 6; text-fig. 59.
Membranilarnacia dikhophora AGELOPOULOS 1967, p. 49-50, pl. 12, figs. 3-4, 6.
Membranilarnaciaursulae(Morgenroth 1966)DECONINCK 1969,p.43, pl. 13, figs. 4-6.
Eatonicysta ursulae (Morgenroth 1966) STOVER and EVITT 1978, p.41
Originally Cannosphaeropsis, subsequently Membranilarnacia, thirdly (and now) Eatonicysta.
Tax. sr. synonym of Membranilarnacia diktyophora Agelopoulos, 1967, according to Eaton, 1976.
Tax. sr. synonym of Membranilarnacia reticulata Williams and Downie, 1966, according to de Coninck, 1969, and Gocht, 1969.
Holotype: Morgenroth, 1966a, pl.3, fig.11; Eisenack and Kjellström, 1972, figure to left - p.143; Fensome et al., 1995, fig.1 - p.1865.
Paratypes: Morgenroth, 1966
Locus typicus: Fehmarn, Katharinenhof, NW Germany
Stratum typicum: Early Eocene
Translation Morgenroth, 1966: LPP
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Eatonicysta ursulae (Morgenroth, 1966a) Stover and Evitt, 1978, emend. Stover and Williams, 1995. According to Stover and Williams (1995, p.106) this species has 17 processes, 10 on the epicyst and 7 on the hypocyst. Processes are solid, partly fibrous to almost completely fibrous and perforate distally where they join the ectophragm. Mesh of ectophragm usually uniform whereas lumina which tend to be polygonal vary in size and shape. Archeopyle apical with only three processes on some opercula.. Process formula is 3-4', 6", 0-4c, 5"’, 1p, 1"”.
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Original description: Morgenroth 1966, p. 20: Cannosphaeropsis ursulae
Diagnosis: A species in the genus Cannosphaeropsis. Thin-walled central body.
16-18 relatively long, solid processes normaly support an envelope consisting of a fine meshwork.
Description: The thin-walled, spherical central body possess a smooth or at least a weakly reticulate surface. On the surface 16-18 evenly distributed, slender, solid processes are present. These support the concentric envelope, which consist in most of the specimens of a extremely delicate, differentiated meshwork (see text fig.12). The processes split up distally forming a fibrous meshwork, which is indistinct on some specimens. A thickening of the meshwork often results in an almost smooth, closed enveloppe. In almost all specimens an irregular shaped pylome, with a denticulate margin, is present. Splitting results in the development of a cap with 3-4 processes, on which the remains of the torn-off outer network are present.
Dimensions: central body diameter: 45-53 Ám; whole cyst diameter: 92-114 Ám; length processes: 6-25 Ám (measured: 100 specimens).
-------------------------------------
For postulated relationships between Eatonicysta ursulae and other species, see Eaton, 1971, and Bujak, 1976.
--------------------------------
Emended description: Stover and Williams 1995, p. 105-106
Shape: Cysts holocavate, autocyst and ectocyst subspherical, shape of ectophragm may be modified by folding.
Wall relationships: Holocavate, autophragm and ectophragm widely separated. ectophragm supported by processes.
Wall features: Autophragm smooth, faintly granular or punctoreticulate; with 17 intratabular processes, 10 on epicyst and seven on hypocyst. Processes solid, partly to almost completely fibroid and somewhat expanded distally where they merge with the ectophragm. Process stems relatively narrow (some slightly wider than others), more or less equal in length. Process length commonly less, but may be equal to, body diameter. Ends of processes generally perforate where they join the ectophragm. Mesh of the ectophragm smooth, narrow and fairly uniform in width whereas the lumina, which tend to be polygonal, vary in size and shape. In general, lumina near processes are smaller than those in intervening
Excystment mode: Archeopyle apical; operculum tetratabular. simple, about equidimensional and free with three or four processes. On opercula with just three processes, a single ventral process presumably represents paraplates 1' and 4'
Paratabulation: Gonyaulacoid, indicated on epicyst by principal and short accessory archeopyle sutures, also by locations of intratabular processes; elsewhere on central body the paratabulation expressed solely by positioning of processes. Process formula: 3-4', 6", 0-4c, 5"', lp, 1"", 0s. First precingular paraplate wider than sixth and process denoting paraplate Ip usually narrower than others. The seven hypocystal processes arranged in standard sexiform pattern.
Paracingulum: Paracingular area lacking processes or may have four processes.
Parasulcus: Parasulcal area without processes; a median parasulcal notch frequently discernible. Presence of sulcal processes not firmly established (see Comments).
Size: Intermediate to large; specimens 85Ám to 135Ám in diameter; autocysts about 40Ám to 55Ám in diameter; processes up to 40Ám in length, most processes between 20Ám and 30Ám.
Comments: Stover and Williams 1995, p. 105-106
The emended descnption indicates that the hypocystal paratabulation is the standard sexiform pattern (text-fig. 1, no. B2), provides additional information about the nature of the ectophragm and modifies the paratabulation formula (text-fig. I, nos. B l-B2). Williams and Downie (1966) recognized two morphotypes of this species, which were informally designated Eatonicysta ursulae Var. a (as Membranilarnacia reticulata Var. a) and Eatonicysta ursulae Var. b (as Membranilarnacia reticulata Var. b). Eatonicysta ursulae Var. a, the commoner of the two, lacked paracingular processes but evidently could have parasulcal processes (although
the occurrence of parasulcal processes has not been confirmed), as opposed to Eatonicysta ursulae Var. b which had four paracingular processes. The presence or absence of parasulcal processes on Eatonicysta ursulae Var. b was not mentioned. Of the numerous specimens of Eatonicysta ursulae available during this study, none were devoid of both paracingular and parasulcal processes.
Stratigraphic and geographic data: Stover and Williams 1995, p. 105-106
The geochronologic range of Eatonicysta ursulae is Early Eocene (Ypresian) to early Mid Eocene (Lutetian). The species does not occur in the earliest Early Eocene. In terms of depositional sequences in the Hampshire Basin, the base of Eatonicysta ursulae lies within the 53 Ma sequence and its top is within the 46.5 Ma sequence. In terms of nannofossil zones, the species ranges from Zone NP 11 to within Zone NP 15, which in turn, correlates with the upper part of planktonic foraminiferal Zone P6B to within Zone P 11. Publications that depict the stratigraphic range of Eatonicysta ursulae are Harker and Sarjeant (1975)--Early to Mid Eocene; these authors also show the species as occurring in the Cenomanian of France (ibid.), but this record has not been confirmed; Williams (1977)--Early [but not earliest] Eocene to early Mid Eocene; Bujak et al. ( 1980)--Early to Mid Eocene, from the base of local palynological Zone LC-2 to the lower part of Zone B-4; Williams and Bujak (1985)--about the middle of the Early Eocene to early Mid Eocene; Powell (1992)--about mid Early Eocene to early Mid Eocene.
Eatonicysta ursulae is confined to the Northern Hemisphere. Confirmed European reports are from England, Germany, Denmark, The Netherlands, Belgium, and Romania. Just two occurrences have been noted outside Europe: offshore eastern Canada, and the eastern North Atlantic. Table S in Costa and Downie (1979) shows the co-occurrence of Eatonicysta ursulae and Apectodinium augustum (Harland 1979) Lentin and Williams 1981 in the Lower Eocene section. In our expenence, the two species are stratigraphically incompatible, with the latter present only in Upper Paleocene strata. In addition, no other definitive record shows Eatonicysta ursulae extending through the Middle Eocene as depicted by Costa and Downie (1979).
Synonym list Stover and Williams 1995, p. 105:
Cannosphaeropsis ursulae MORGENROTH 1966, p.20, pl.3, figs.11 - 12.
Membranilarnacia reticulala WILLIAMS and DOWNIE 1966, p.220-222, pl. 24, figs. 4, 6; text-fig. 59.
Membranilarnacia dikhophora AGELOPOULOS 1967, p. 49-50, pl. 12, figs. 3-4, 6.
Membranilarnaciaursulae(Morgenroth 1966)DECONINCK 1969,p.43, pl. 13, figs. 4-6.
Eatonicysta ursulae (Morgenroth 1966) STOVER and EVITT 1978, p.41