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Hafniasphaera septata
Hafniasphaera septata (Cookson and Eisenack, 1967b, p.253–254, pl.42, figs.6–10; text-fig.1) Hansen, 1977, p.16. Emendation: McLean, 1971, p.730, as Spiniferites septatus.
Originally Baltisphaeridium (Acritarch), subsequently Spiniferites, thirdly (and now) Hafniasphaera, fourthly Achomosphaera, fifthly Rivernookia. Stover and Williams, 1987, retained this species in Spiniferites. Williams et al. (1998, p.261) retained this species in Hafniasphaera.
Holotype: Cookson and Eisenack, 1967b, pl.42, fig.6; Eisenack and Kjellström, 1975b, uppermost figure — p.984w; Fensome et al., 1996, fig.1 — p.2356.
Locus typicus: Rivernook Member of Dilwyn Clay, Victoria, Australia
Stratum typicum: Late Paleocene
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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.
Hafniasphaera septata (Cookson and Eisenack, 1967b) Hansen, 1977, emend. McLean, 1971. Diagnosis modified from Cookson and Eisenack (1967b), shell spherical, thin-walled with a closely and rather coarsely, apparently granular surface and a variable number of radially arranged processes, whose length is approximately equal to the radius of the shell. A “marginal zone” often present, giving the impression that the shell is thick-walled, is in fact due to compression. The processes vary in size, shape and structure. The majority narrow somewhat from a broadened base and divide distally into two or three straight or curved tapering branches with closed, pointed or minutely bifurcate tips. The larger processes are typically hollow and septate throughout; however, in the finer to thread-like ones, the degree of septation is often difficult to determine and their distal portions at least appear to be solid. A few of the processes are unbranched.An archeopyle has been seen in a few specimens Emended description, from McLean (1972). Cyst main body spheroidal to ovoidal with gonally and intergonally distributed processes; process positions in conjunction with rarely developed, weakly defined sutural ridges indicate tabulation of 3', 0a, 6", 6c, 5?”’, 1p, 1"”. Archeopyle precingular (Type P) with simple, free operculum; corresponds to plate 3". Cingulum reflected by processes; laevorotatory; ends displaced vertically about one cingulum width. Hypotract ventral tabulation weakly developed, obscuring sulcal outline. Cyst wall appears bilayered in optical section, with compact inner layer about 1 µm thick and an outer layer 1.5-3 µm thick (constant for a specimen) constructed of closely appressed, bubble-like elements up to 2.5 µm in diameter. Processes parallel sided to slightly tapering, with bluntly rounded closed tips; two to three relatively small, essentially parallel sided, blunt tipped branches (that may also be branched) extend from most process tips. Process bases constructed of bubble-like elements; process trunks and branches hollow but compartmented by transverse septa. Size: holotype, overall diameter ca. 80 µm, diameter of shell ca. 57 µm, processes 10-18 µm, range overall diameter 42-58 µm.
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Original diagnosis: Cookson and Eisenack, 1967, p.253: Baltisphaeridium septatum
Shell spherical, thin-walled with a closely and rather coarsely apparently granular surface and a variable number of radially arranged appendages which approximate in length to the radius of the shell. A "marginal zone" often present, given the impression that the shell is thick-walled, is, in fact, due to compression.
Original description: Cookson and Eisenack, 1967, p.253: Baltisphaeridium septatum
The appendages vary in size, shape and structure. The majority narrow somewhat from a broadened base and divide distally into two or three straight or curved tapering branches with closed, pointed or minutely bifurcate tips. The larger appendages are typically hollow and septate throughout; in the finer to thread-like ones, on the contrary the degree of septation is often difficult to determine and their distal portions, at least, appear to be solid. A few of the appendages are unbranched. A pylome has been seen in a few specimens.
Dimensions: Holotype: overall diameter c. 80 µm diameter of shell c. 57 µm, appendages 10-18 µm long. Range: shell diameter c. 42-58 µm.
Originally Baltisphaeridium (Acritarch), subsequently Spiniferites, thirdly (and now) Hafniasphaera, fourthly Achomosphaera, fifthly Rivernookia. Stover and Williams, 1987, retained this species in Spiniferites. Williams et al. (1998, p.261) retained this species in Hafniasphaera.
Holotype: Cookson and Eisenack, 1967b, pl.42, fig.6; Eisenack and Kjellström, 1975b, uppermost figure — p.984w; Fensome et al., 1996, fig.1 — p.2356.
Locus typicus: Rivernook Member of Dilwyn Clay, Victoria, Australia
Stratum typicum: Late Paleocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hafniasphaera septata (Cookson and Eisenack, 1967b) Hansen, 1977, emend. McLean, 1971. Diagnosis modified from Cookson and Eisenack (1967b), shell spherical, thin-walled with a closely and rather coarsely, apparently granular surface and a variable number of radially arranged processes, whose length is approximately equal to the radius of the shell. A “marginal zone” often present, giving the impression that the shell is thick-walled, is in fact due to compression. The processes vary in size, shape and structure. The majority narrow somewhat from a broadened base and divide distally into two or three straight or curved tapering branches with closed, pointed or minutely bifurcate tips. The larger processes are typically hollow and septate throughout; however, in the finer to thread-like ones, the degree of septation is often difficult to determine and their distal portions at least appear to be solid. A few of the processes are unbranched.An archeopyle has been seen in a few specimens Emended description, from McLean (1972). Cyst main body spheroidal to ovoidal with gonally and intergonally distributed processes; process positions in conjunction with rarely developed, weakly defined sutural ridges indicate tabulation of 3', 0a, 6", 6c, 5?”’, 1p, 1"”. Archeopyle precingular (Type P) with simple, free operculum; corresponds to plate 3". Cingulum reflected by processes; laevorotatory; ends displaced vertically about one cingulum width. Hypotract ventral tabulation weakly developed, obscuring sulcal outline. Cyst wall appears bilayered in optical section, with compact inner layer about 1 µm thick and an outer layer 1.5-3 µm thick (constant for a specimen) constructed of closely appressed, bubble-like elements up to 2.5 µm in diameter. Processes parallel sided to slightly tapering, with bluntly rounded closed tips; two to three relatively small, essentially parallel sided, blunt tipped branches (that may also be branched) extend from most process tips. Process bases constructed of bubble-like elements; process trunks and branches hollow but compartmented by transverse septa. Size: holotype, overall diameter ca. 80 µm, diameter of shell ca. 57 µm, processes 10-18 µm, range overall diameter 42-58 µm.
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Original diagnosis: Cookson and Eisenack, 1967, p.253: Baltisphaeridium septatum
Shell spherical, thin-walled with a closely and rather coarsely apparently granular surface and a variable number of radially arranged appendages which approximate in length to the radius of the shell. A "marginal zone" often present, given the impression that the shell is thick-walled, is, in fact, due to compression.
Original description: Cookson and Eisenack, 1967, p.253: Baltisphaeridium septatum
The appendages vary in size, shape and structure. The majority narrow somewhat from a broadened base and divide distally into two or three straight or curved tapering branches with closed, pointed or minutely bifurcate tips. The larger appendages are typically hollow and septate throughout; in the finer to thread-like ones, on the contrary the degree of septation is often difficult to determine and their distal portions, at least, appear to be solid. A few of the appendages are unbranched. A pylome has been seen in a few specimens.
Dimensions: Holotype: overall diameter c. 80 µm diameter of shell c. 57 µm, appendages 10-18 µm long. Range: shell diameter c. 42-58 µm.