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Alterbidinium minus
From Fensome et al., 2019:
Alterbidinium minus, (Alberti, 1959b, p.98, pl.9, figs.9–11) Lentin and Williams, 1985, p.14.
Emendation: Khowaja-Ateequzzaman et al., 1991, p.44, as Alterbidinium minus.
Holotype: Alberti, 1959b, pl.9, fig.10.
Originally Deflandrea, subsequently Alterbia (combination illegitimate), thirdly (and now) Alterbidinium.
Age: late Senonian.
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Original description [translation pkb 2024], Alberti, 1959: Deflandrea minor n. sp. (plate 9 Fig. 9-11)
Holotype: The specimen preserved in preparation no. Oeb/S2 and shown on plate 9, fig. 10.
Locus typicus: Oebisfelde borehole (Altmark).
Stratum typicum: Upper “Senon”.
Diagnosis: Carapace flattened, its outline elongated pentagonal to almost rhombic, lateral edges often convex. The epithek, which forms an approximately right-angled triangle, is almost as large as the mortgage and extends into a small ± separated apical horn. Transverse furrow usually absent, shallowly deepened if present. Usually only a small, pointed antapical horn is formed, rarely the second one is indicated (Fig. 10). With a delicate inner body that is not always close to the outer edge of the shell. His and the carapace's surface is finely dotted.
Additions: The apical horn is slightly blunted at its free end. In a few specimens the second antapical horn is also present in the form of a small projection. The carapace is sometimes notched at the level of the completely reduced side horns. A rounded hexagonal hatch lies just below the apex.
Differential diagnosis: The species is characterized by its small dimensions compared to most representatives of the genus. By Defl. parva Cooks. & Eisenack it differs in the outline of the shell, the absence of a transverse furrow and the shape of the inner body.
Dimensions of the holotype: length 52 μ, width 36 μ. In other specimens, the length varies between 44 μ and 68 μ and the width between 29 μ and 46 μ.
Fabric: Over 20 copies.
Occurrence: Upper "Senon" of the Oebisfelde borehole (Altmark).
Emended diagnosis: Khowaja Ateequzzaman et al., 1991, p.44-45
Cyst proximate, dorsoventrally compressed, circumcavate, pericyst ambitus pentagonal with an apical and two unequal antapical horns, right antapical horn reduced; periphragm thin, smooth; endocyst subpentagonal, endophragm thicker than periphragm, smooth; periparacingulum absent, paratabulation indicated by archaeopyle alone; archaeopyle intercalary, independently developed on periphragm and endophragm, periarchaeopyle hexa 2a, steno-deltaform, perioperculum adnate, endoarchaeopyle hexa 2a, eury-deltaform, endoperculum adnate.
Description:
Shape--Cyst proximate, dorso-ventrally compressed; pericyst ambitus pentagonal with an apical horn and two unequal antapical horns, right antapical horn reduced; endocyst subpentagonal.
Wall relationship--Apical and antapical pericoels prominent, connected through ambital pericoel (circumcavate); endocyst shifted more towards dorsal side where periphragm and endophragm appressed in the precingular and postcingular areas.
Wall features--No parasutural features; periphragm thin, smooth; endophragm relatively thick, smooth, at times a short apicular process present, paracingulum absent.
Paratabulation--Indicated by archaeopyle alone.
Archaeopyle--Intercalary, independently developed on periphragm and endophragm; periarchaeopyle hexa 2a, steno-deltaform, perioperculum adnate (adnation along adcingular margin); endoarchaeopyle hexa 2a, eury-deltaform, endoperculum adnate (adnation along adcingular margin).
Alterbidinium minus, (Alberti, 1959b, p.98, pl.9, figs.9–11) Lentin and Williams, 1985, p.14.
Emendation: Khowaja-Ateequzzaman et al., 1991, p.44, as Alterbidinium minus.
Holotype: Alberti, 1959b, pl.9, fig.10.
Originally Deflandrea, subsequently Alterbia (combination illegitimate), thirdly (and now) Alterbidinium.
Age: late Senonian.
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Original description [translation pkb 2024], Alberti, 1959: Deflandrea minor n. sp. (plate 9 Fig. 9-11)
Holotype: The specimen preserved in preparation no. Oeb/S2 and shown on plate 9, fig. 10.
Locus typicus: Oebisfelde borehole (Altmark).
Stratum typicum: Upper “Senon”.
Diagnosis: Carapace flattened, its outline elongated pentagonal to almost rhombic, lateral edges often convex. The epithek, which forms an approximately right-angled triangle, is almost as large as the mortgage and extends into a small ± separated apical horn. Transverse furrow usually absent, shallowly deepened if present. Usually only a small, pointed antapical horn is formed, rarely the second one is indicated (Fig. 10). With a delicate inner body that is not always close to the outer edge of the shell. His and the carapace's surface is finely dotted.
Additions: The apical horn is slightly blunted at its free end. In a few specimens the second antapical horn is also present in the form of a small projection. The carapace is sometimes notched at the level of the completely reduced side horns. A rounded hexagonal hatch lies just below the apex.
Differential diagnosis: The species is characterized by its small dimensions compared to most representatives of the genus. By Defl. parva Cooks. & Eisenack it differs in the outline of the shell, the absence of a transverse furrow and the shape of the inner body.
Dimensions of the holotype: length 52 μ, width 36 μ. In other specimens, the length varies between 44 μ and 68 μ and the width between 29 μ and 46 μ.
Fabric: Over 20 copies.
Occurrence: Upper "Senon" of the Oebisfelde borehole (Altmark).
Emended diagnosis: Khowaja Ateequzzaman et al., 1991, p.44-45
Cyst proximate, dorsoventrally compressed, circumcavate, pericyst ambitus pentagonal with an apical and two unequal antapical horns, right antapical horn reduced; periphragm thin, smooth; endocyst subpentagonal, endophragm thicker than periphragm, smooth; periparacingulum absent, paratabulation indicated by archaeopyle alone; archaeopyle intercalary, independently developed on periphragm and endophragm, periarchaeopyle hexa 2a, steno-deltaform, perioperculum adnate, endoarchaeopyle hexa 2a, eury-deltaform, endoperculum adnate.
Description:
Shape--Cyst proximate, dorso-ventrally compressed; pericyst ambitus pentagonal with an apical horn and two unequal antapical horns, right antapical horn reduced; endocyst subpentagonal.
Wall relationship--Apical and antapical pericoels prominent, connected through ambital pericoel (circumcavate); endocyst shifted more towards dorsal side where periphragm and endophragm appressed in the precingular and postcingular areas.
Wall features--No parasutural features; periphragm thin, smooth; endophragm relatively thick, smooth, at times a short apicular process present, paracingulum absent.
Paratabulation--Indicated by archaeopyle alone.
Archaeopyle--Intercalary, independently developed on periphragm and endophragm; periarchaeopyle hexa 2a, steno-deltaform, perioperculum adnate (adnation along adcingular margin); endoarchaeopyle hexa 2a, eury-deltaform, endoperculum adnate (adnation along adcingular margin).