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Alterbia balmei
Alterbia balmei, (Cookson and Eisenack, 1962), Lentin and Williams 1976; Emendation: Morgan 1977
NOW Spinidinium balmei. Originally Deflandrea minor (name illegitimate), subsequently Deflandrea balmei, thirdly Alterbia balmei (combination illegitimate), fourthly Isabelidinium balmei, fifthly (and now) Spinidinium balmei, sixthly Magallanesium balmei.
Taxonomic senior synonym: Palaeohystrichophora (as Diconodinium) minuta, according to Morgan (1977, p.130) — however, Lentin and Williams (1981, p.156) retained Deflandrea (as Isabelidinium, now Spinidinium) balmei.
Holotype: Cookson and Eisenack, 1960a, pl.1, fig.1; Morgan, 1977, text-fig.2.
Locus typicus: Carnarvon Basin, W Australia
Stratum typicum: Turonian
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Original description as Deflandrea minor: [Cookson and Eisenack, 1960, p. 2]:
Description:
Shell approximately oval, divided by a shallow but relatively broad girdle. The epitheca tapers to a short truncate or convex apex; the hypotheca is broadly rounded, with one or two small lateral points of unequal size. A rather broad longitudinal furrow is usually evident. The capsule is circular in outline and does not fill the shell laterally. The shell membrane is sparsely covered with small spines, which tend to be linearly arranged on the general surface as well as on the borders of the girdle and longitudinal furrow. The wall of the capsule is thin and smooth. The pylome is small and semicircular to trapezoid.
Dimensions:
Holotype - 52 µm long; 40 µm broad; capsule 33 µm.
Range - 45-65 µm long; 37-43 µm broad.
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Emended description:
Morgan, 1977, p. 130:
Description:
Broadly rhomboidal to subpentagonal ambitus, with a truncate apical horn and one, or two unequal, sharp antapical horn(s) on the periphragm and an ellipsoidal endophragm. The apical and antapical pericoels may be united by an ambital pericoel. The periphragm uniformly thin, and drawn into small, 2 µm high, sharply pointed spines. The endophragm is thin and psilate. Traces of paratabulation sometimes discernible by sutural alignment of spines on pericyst; pericingulum defined by two slightly raised ridges bearing aligned granules, slightly helicoidal, individual paraplates not seen; perisulcus psilate; periarcheopyle standard hexa la (2a only); endophragm psilate, endoarcheopyle not clearly discernible, probably la.
Dimensions:
45-65 µm long and 37-43 µm broad.
NOW Spinidinium balmei. Originally Deflandrea minor (name illegitimate), subsequently Deflandrea balmei, thirdly Alterbia balmei (combination illegitimate), fourthly Isabelidinium balmei, fifthly (and now) Spinidinium balmei, sixthly Magallanesium balmei.
Taxonomic senior synonym: Palaeohystrichophora (as Diconodinium) minuta, according to Morgan (1977, p.130) — however, Lentin and Williams (1981, p.156) retained Deflandrea (as Isabelidinium, now Spinidinium) balmei.
Holotype: Cookson and Eisenack, 1960a, pl.1, fig.1; Morgan, 1977, text-fig.2.
Locus typicus: Carnarvon Basin, W Australia
Stratum typicum: Turonian
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Original description as Deflandrea minor: [Cookson and Eisenack, 1960, p. 2]:
Description:
Shell approximately oval, divided by a shallow but relatively broad girdle. The epitheca tapers to a short truncate or convex apex; the hypotheca is broadly rounded, with one or two small lateral points of unequal size. A rather broad longitudinal furrow is usually evident. The capsule is circular in outline and does not fill the shell laterally. The shell membrane is sparsely covered with small spines, which tend to be linearly arranged on the general surface as well as on the borders of the girdle and longitudinal furrow. The wall of the capsule is thin and smooth. The pylome is small and semicircular to trapezoid.
Dimensions:
Holotype - 52 µm long; 40 µm broad; capsule 33 µm.
Range - 45-65 µm long; 37-43 µm broad.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Morgan, 1977, p. 130:
Description:
Broadly rhomboidal to subpentagonal ambitus, with a truncate apical horn and one, or two unequal, sharp antapical horn(s) on the periphragm and an ellipsoidal endophragm. The apical and antapical pericoels may be united by an ambital pericoel. The periphragm uniformly thin, and drawn into small, 2 µm high, sharply pointed spines. The endophragm is thin and psilate. Traces of paratabulation sometimes discernible by sutural alignment of spines on pericyst; pericingulum defined by two slightly raised ridges bearing aligned granules, slightly helicoidal, individual paraplates not seen; perisulcus psilate; periarcheopyle standard hexa la (2a only); endophragm psilate, endoarcheopyle not clearly discernible, probably la.
Dimensions:
45-65 µm long and 37-43 µm broad.