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Nannoceratopsis ambonis
Nannoceratopsis ambonis Drugg, 1978; emend. Riding, 1984
Holotype: Drugg, 1978, pl.6, fig.3
Isotypes: Drugg, 1978
Locus typicus: Eschach, Swabia, Germany
Stratum typicum: Aalenian
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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.
Nannoceratopsis ambonis Drugg, 1978, emend. Riding, 1984a. This species has a prominently thickened saggital band and is Late Pliensbachian-Late Bajocian. According to Riding (1984a), this species has two unequal antapical horns. Autophragm smooth to finely granulate. The width of a single sagittal band is 4-9% of the maximum cyst width. Size: length 60-82 µm, width 36-51 µm.
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Original description: Drugg, 1978, p. 70
Outline subtriangular. The dorsal and ventral antapical horns are sometimes more or less equal with a shallow antapical cavity. In most cases, however, the dorsal horn is moderately long and the ventral horn is reduced. The wall is thin and shagreen to finely granulate. The striking feature about this species is the presence of ridges which border the lateral edges of the cyst. Sometimes these ridges are heavy and solid. At other times they are broken into segmments. Occasionally the ridges take the form of a coarse reticulate border. the total length ranges from 62 to 80 Ám. measurements based on 22 specimens.
Emended diagnosis: Riding, 1984, p. 76
Species of Nannoceratopsis which is subtriangular in outline. Two antapical horns are present separated by a cancave antapical margin; usually the dorsal horn is longest, the ventral horn normally being markedly reduced. The autophragm is smooth to finely granulate. At the sagittal band the autophragm is prominently thickened, prodducing a distinctive continuous solid rim around the hypocyst when seen in lateral view. When observed in lateral view the width of a single sagittal band comprises 4-9% of the maximum cyst breadth. Archaeopylee cingular (Piel and Evitt, 1980).
Dimensions: Length 60(66)82 Ám, width 36(41)51 Ám (20 specimens measured).
Affinities:
Drugg 1978, p. 71: Nannoceratopsis ambonis differs from N. gracilis Alberti, 1961, in possessing a non-reticulate wall and in possessing distinct ridged lateral edges. It differs from N. senex Van Helden, 1977, in the presence of the ridges and also in outline.
Riding, 1984, p. 76: N. ambonis is similar in shape and overall morphology to N. gracilis Alberti, 1961, but differs by having a prominent thickenedd solid sagittal band. The above emendation restricts N. ambonis to forms with solid, unbroken, thickened sagittal bands, thereby excluding morphotypes with reticulate thickened sagittal areas (see N. dictyambonis Riding, 1984).
Holotype: Drugg, 1978, pl.6, fig.3
Isotypes: Drugg, 1978
Locus typicus: Eschach, Swabia, Germany
Stratum typicum: Aalenian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Nannoceratopsis ambonis Drugg, 1978, emend. Riding, 1984a. This species has a prominently thickened saggital band and is Late Pliensbachian-Late Bajocian. According to Riding (1984a), this species has two unequal antapical horns. Autophragm smooth to finely granulate. The width of a single sagittal band is 4-9% of the maximum cyst width. Size: length 60-82 µm, width 36-51 µm.
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Original description: Drugg, 1978, p. 70
Outline subtriangular. The dorsal and ventral antapical horns are sometimes more or less equal with a shallow antapical cavity. In most cases, however, the dorsal horn is moderately long and the ventral horn is reduced. The wall is thin and shagreen to finely granulate. The striking feature about this species is the presence of ridges which border the lateral edges of the cyst. Sometimes these ridges are heavy and solid. At other times they are broken into segmments. Occasionally the ridges take the form of a coarse reticulate border. the total length ranges from 62 to 80 Ám. measurements based on 22 specimens.
Emended diagnosis: Riding, 1984, p. 76
Species of Nannoceratopsis which is subtriangular in outline. Two antapical horns are present separated by a cancave antapical margin; usually the dorsal horn is longest, the ventral horn normally being markedly reduced. The autophragm is smooth to finely granulate. At the sagittal band the autophragm is prominently thickened, prodducing a distinctive continuous solid rim around the hypocyst when seen in lateral view. When observed in lateral view the width of a single sagittal band comprises 4-9% of the maximum cyst breadth. Archaeopylee cingular (Piel and Evitt, 1980).
Dimensions: Length 60(66)82 Ám, width 36(41)51 Ám (20 specimens measured).
Affinities:
Drugg 1978, p. 71: Nannoceratopsis ambonis differs from N. gracilis Alberti, 1961, in possessing a non-reticulate wall and in possessing distinct ridged lateral edges. It differs from N. senex Van Helden, 1977, in the presence of the ridges and also in outline.
Riding, 1984, p. 76: N. ambonis is similar in shape and overall morphology to N. gracilis Alberti, 1961, but differs by having a prominent thickenedd solid sagittal band. The above emendation restricts N. ambonis to forms with solid, unbroken, thickened sagittal bands, thereby excluding morphotypes with reticulate thickened sagittal areas (see N. dictyambonis Riding, 1984).