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Hapsocysta benteae
Hapsocysta? benteae Nohr-Hansen, 1993
Holotype: Nohr-Hansen, 1993, pl.25, fig.11, text-fig.10
Locus typicus: Stratum bjerg, Wollaston Foreland, East Greenland
Stratum typicum: Albian
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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.
Hapsocysta benteae Nøhr_Hansen, 1993. According to Nøhr-Hansen (1993), Hapsocysta benteae is represented by camocavate, lenticular cysts with a circular equatorial outline in polar view. The cysts are thin-walled, hyaline and apically/antapically compressed with a smaller, spherical, dorsally attached endocyst with a smooth surface. The periphragm surface is also smooth but ornamented with low sutural ribs reflecting a gonyaulacoid tabulation. A precingular archeopyle (type P) may be distinguished on the dorsal side, whereas a sulcal opening (an opisthopyle) is always present on the ventral surface of the pericyst. Note that in this species the as and 4' are in contact. Hapsocysta benteae is questionably included in Hapsocysta because it has a thin-walled periphragm. It differs from Stephodinium australicum by the smaller diameter of the pericyst, by being apically/antapically compressed, by being tabulate and by having an endocyst situated dorsally. Size: diameter of pericyst 60-85 µm, endocyst diameter 36-45 µm.
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Original diagnosis: Nohr-Hansen, 1993, p.71
The species is represented by camocavate, lenticular cysts with a circular equatorial outline in polar view. The cysts are thin-walled, hyaline and apical/antapically compressed with a smaller, spherical, dorsally attached endocyst with a smooth surface. The surface of the periphragm is also smooth but ornamented by low sutural ribs reflecting a gonyaulacoid tabulation pattern. A precingular archeopyle (type P) may be distinguished on the dorsal side, whereas a sulcal opening (an opisthopyle) is always present on the ventral surface of the pericyst.
Original description: Nohr-Hansen, 1993, p.71
Cyst type. Camocavate with a large ventral pericoel.
Shape. The cyst is lenticular with a circular equatorial outline in polar view.
Wall relationships. The cyst is composed of a thin-walled (less than 1Á), hyaline, tabulate pericyst, and a smaller endocyst approximately half the diameter of the pericyst. The endocyst is smooth thin walled, hyaline, lenticular with a circular equatorial outline in polar view and often folded probably due to the apical/antapical compression of the cyst. Periphragm and endophragm are dorsally appressed.
Tabulation. Low sutural ribs on the periphragm indicate tabulation, which is gonyaulacoid with an S-type ventral pattern (Evitt, 1985). Formula ?4', 6", 6c, 1p, 6''', 1'''' (Figs 10-11). Five sulcal plates have been distinguished: the posterior sulcal plate (ps), the right sulcal plate (rs), the left sulcal plate (Is), the right accessory plate (ras) and the anterior sulcal plate (as). An almost circular opening in the sulcal area (an opisthopyle) is always present on the pericyst. The opening is demarcated by the plates: as, ras, rs, Is and 1''' (Figs.10-11).
Archeopyle. A precingular archeopyle may be distinguished on the dorsal side.
Dimensions. Holotype: diameter of pericyst 78 µm, diameter of endocyst 44 µm.
Size range. Diameter of pericyst 60(71)85 µm (10 specimens), diameter of endocyst 36(40)45 µm (10 specimens).
Affinities:
Nohr-Hansen, 1993, p.72: Hapsocysta? benteae differs from Stephodinium australicum by the smaller diameter of the pencyst, by being apical/antapically compressed, by being tabulate and by having the endocyst situated dorsally. The equatorial, wing-like outgrowth described and illustrated by Cookson and Eisenack (1962, p. 491, plate 2, figs 6-9) has not been observed in the present material.
Holotype: Nohr-Hansen, 1993, pl.25, fig.11, text-fig.10
Locus typicus: Stratum bjerg, Wollaston Foreland, East Greenland
Stratum typicum: Albian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Hapsocysta benteae Nøhr_Hansen, 1993. According to Nøhr-Hansen (1993), Hapsocysta benteae is represented by camocavate, lenticular cysts with a circular equatorial outline in polar view. The cysts are thin-walled, hyaline and apically/antapically compressed with a smaller, spherical, dorsally attached endocyst with a smooth surface. The periphragm surface is also smooth but ornamented with low sutural ribs reflecting a gonyaulacoid tabulation. A precingular archeopyle (type P) may be distinguished on the dorsal side, whereas a sulcal opening (an opisthopyle) is always present on the ventral surface of the pericyst. Note that in this species the as and 4' are in contact. Hapsocysta benteae is questionably included in Hapsocysta because it has a thin-walled periphragm. It differs from Stephodinium australicum by the smaller diameter of the pericyst, by being apically/antapically compressed, by being tabulate and by having an endocyst situated dorsally. Size: diameter of pericyst 60-85 µm, endocyst diameter 36-45 µm.
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Original diagnosis: Nohr-Hansen, 1993, p.71
The species is represented by camocavate, lenticular cysts with a circular equatorial outline in polar view. The cysts are thin-walled, hyaline and apical/antapically compressed with a smaller, spherical, dorsally attached endocyst with a smooth surface. The surface of the periphragm is also smooth but ornamented by low sutural ribs reflecting a gonyaulacoid tabulation pattern. A precingular archeopyle (type P) may be distinguished on the dorsal side, whereas a sulcal opening (an opisthopyle) is always present on the ventral surface of the pericyst.
Original description: Nohr-Hansen, 1993, p.71
Cyst type. Camocavate with a large ventral pericoel.
Shape. The cyst is lenticular with a circular equatorial outline in polar view.
Wall relationships. The cyst is composed of a thin-walled (less than 1Á), hyaline, tabulate pericyst, and a smaller endocyst approximately half the diameter of the pericyst. The endocyst is smooth thin walled, hyaline, lenticular with a circular equatorial outline in polar view and often folded probably due to the apical/antapical compression of the cyst. Periphragm and endophragm are dorsally appressed.
Tabulation. Low sutural ribs on the periphragm indicate tabulation, which is gonyaulacoid with an S-type ventral pattern (Evitt, 1985). Formula ?4', 6", 6c, 1p, 6''', 1'''' (Figs 10-11). Five sulcal plates have been distinguished: the posterior sulcal plate (ps), the right sulcal plate (rs), the left sulcal plate (Is), the right accessory plate (ras) and the anterior sulcal plate (as). An almost circular opening in the sulcal area (an opisthopyle) is always present on the pericyst. The opening is demarcated by the plates: as, ras, rs, Is and 1''' (Figs.10-11).
Archeopyle. A precingular archeopyle may be distinguished on the dorsal side.
Dimensions. Holotype: diameter of pericyst 78 µm, diameter of endocyst 44 µm.
Size range. Diameter of pericyst 60(71)85 µm (10 specimens), diameter of endocyst 36(40)45 µm (10 specimens).
Affinities:
Nohr-Hansen, 1993, p.72: Hapsocysta? benteae differs from Stephodinium australicum by the smaller diameter of the pencyst, by being apical/antapically compressed, by being tabulate and by having the endocyst situated dorsally. The equatorial, wing-like outgrowth described and illustrated by Cookson and Eisenack (1962, p. 491, plate 2, figs 6-9) has not been observed in the present material.