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Kallosphaeridium biornatum
Kallosphaeridium biornatum Stover, 1977; emend. Jan du Chene et al., 1985
Sr. homonym of Kallosphaeridium biornatum (Jiabo, 1978) Lentin and Williams, 1981
Holotype: Stover, 1977, pl.1, figs.9-10
Locus typicus: Corehole 5/5B, Blake Plateau, Western N Atlantic
Stratum typicum: Early Oligocene
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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.
Kallosphaeridium biornatum Stover, 1977, emend. Jan du Chêne et al., 1985a. According to Jan du Chêne et al. (1985a), Kallosphaeridium biornatum is subspherical with a thin (about 1 µm) autophragm whose outer surface is punctoreticulate and bears scattered, nontabular cones and or short spines. The paratabulation is indicated by the principal and accessory archeopyle sutures; other indications are lacking as are those of a paracingulum and parasulcus. Archeopyle sutures and opercular outline indicate an epicystal paratabulation formula of 4', 1a, 6". Archeopyle type [4AI]@; isthmus narrow, constituent paraplates not delimited on operculum. Opercula are small relative to the cyst diameter. Operculum width (OW), cyst width (CD) ratio = 0.30. Size: diameter 53-65 µm.
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Original dscription: Stover, 1977, p. 74
Cysts are subspherical, however, their shape is nearly always modified by folding. Autophragm thin, about 1 Ám, with punctoreticulate outer surface together with scattered,nontabular cones and short spines. Archeopyle is apical, type Aa, and its principal suture is angular; accessory archeopyle sutures typically present between precingular paraplates. Operculum small relative to cyst diameter, attached ventrally to rest of cyst by narrow isthmus, and its constituent apical paraplates are not differentiated on opercular surface. Paratabulation indicated by archeopyle and accessory sutures that delineate precingular paraplates. Indications of paracingulum and parasulcus normally absent.
Overall size 54 to 63 Ám.
Affinities: Stover, 1977, p. 74
Kallosphaeridium biornatum differs from K. brevibarbatum De Coninck, 1969 by having punctoreticulate ornamentation with widely scattered cones and spinules on the autophragm rather than a dense covering of hairlike structures. In addition, the autophragm of K. biornatum appears to be appreciably thinner than that of K. brevibarbatum.
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Heilmann-Clausen in Heilmann-Clausen and Costa, 1989, p. 469, pl.19, figs.1,5,6: Kallosphaeridium biornatum group
The operculum is broken off in nearly all specimens recovered. The narrow isthmus anterior to the parasulcus, at which the operculum was attached, is often clearly visible. Possibly, some of the precingular paraplates are also lost in these forms, and the assignment to K. biornatum is therefore provisional.
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Jan du Chene et al. 1985a, p. 9-10
The emended description below differs from the original description (Stover 1977, 73-74) only in that archeopyle type is changed from Aa to [4AI] @.
Emended description: Jan du Chene et al. 1985a, p. 9-10
Subspherical proximate cysts with a thin (about 1 Ám) autophragm whose outer surface is punctoreticulate and bears scattered, nontabular cones and/or short spines. The paratabulation is indicated by the principal and accessory archeopyle sutures; other indications are lacking as are those of a paracingulum and parasulcus. Archeopyle sutures and opercular outline indicate an epicystal paratabulation formula of 4', 1a, 6". Archeopyle type [4AI]@; isthmus narrow, constituent paraplates not delineated on operculum. Opercula are small relative to cyst diameter; OW/CD ratio = 0.30. Diameter between 53 and 65 Ám; 5 specimens measured.
Sr. homonym of Kallosphaeridium biornatum (Jiabo, 1978) Lentin and Williams, 1981
Holotype: Stover, 1977, pl.1, figs.9-10
Locus typicus: Corehole 5/5B, Blake Plateau, Western N Atlantic
Stratum typicum: Early Oligocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Kallosphaeridium biornatum Stover, 1977, emend. Jan du Chêne et al., 1985a. According to Jan du Chêne et al. (1985a), Kallosphaeridium biornatum is subspherical with a thin (about 1 µm) autophragm whose outer surface is punctoreticulate and bears scattered, nontabular cones and or short spines. The paratabulation is indicated by the principal and accessory archeopyle sutures; other indications are lacking as are those of a paracingulum and parasulcus. Archeopyle sutures and opercular outline indicate an epicystal paratabulation formula of 4', 1a, 6". Archeopyle type [4AI]@; isthmus narrow, constituent paraplates not delimited on operculum. Opercula are small relative to the cyst diameter. Operculum width (OW), cyst width (CD) ratio = 0.30. Size: diameter 53-65 µm.
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Original dscription: Stover, 1977, p. 74
Cysts are subspherical, however, their shape is nearly always modified by folding. Autophragm thin, about 1 Ám, with punctoreticulate outer surface together with scattered,nontabular cones and short spines. Archeopyle is apical, type Aa, and its principal suture is angular; accessory archeopyle sutures typically present between precingular paraplates. Operculum small relative to cyst diameter, attached ventrally to rest of cyst by narrow isthmus, and its constituent apical paraplates are not differentiated on opercular surface. Paratabulation indicated by archeopyle and accessory sutures that delineate precingular paraplates. Indications of paracingulum and parasulcus normally absent.
Overall size 54 to 63 Ám.
Affinities: Stover, 1977, p. 74
Kallosphaeridium biornatum differs from K. brevibarbatum De Coninck, 1969 by having punctoreticulate ornamentation with widely scattered cones and spinules on the autophragm rather than a dense covering of hairlike structures. In addition, the autophragm of K. biornatum appears to be appreciably thinner than that of K. brevibarbatum.
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Heilmann-Clausen in Heilmann-Clausen and Costa, 1989, p. 469, pl.19, figs.1,5,6: Kallosphaeridium biornatum group
The operculum is broken off in nearly all specimens recovered. The narrow isthmus anterior to the parasulcus, at which the operculum was attached, is often clearly visible. Possibly, some of the precingular paraplates are also lost in these forms, and the assignment to K. biornatum is therefore provisional.
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Jan du Chene et al. 1985a, p. 9-10
The emended description below differs from the original description (Stover 1977, 73-74) only in that archeopyle type is changed from Aa to [4AI] @.
Emended description: Jan du Chene et al. 1985a, p. 9-10
Subspherical proximate cysts with a thin (about 1 Ám) autophragm whose outer surface is punctoreticulate and bears scattered, nontabular cones and/or short spines. The paratabulation is indicated by the principal and accessory archeopyle sutures; other indications are lacking as are those of a paracingulum and parasulcus. Archeopyle sutures and opercular outline indicate an epicystal paratabulation formula of 4', 1a, 6". Archeopyle type [4AI]@; isthmus narrow, constituent paraplates not delineated on operculum. Opercula are small relative to cyst diameter; OW/CD ratio = 0.30. Diameter between 53 and 65 Ám; 5 specimens measured.