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Isabelidinium seelandicum
Isabelidinium seelandicum (Lange, 1969) Lentin and Williams, 1977; Emendation: Firth, 1987, p.213–214, as Manumiella seelandica.
NOW Manumiella. Originally Broomea, subsequently Isabelia (combination illegitimate), thirdly Isabelidinium, fourthly (and now) Manumiella.
Taxonomic junior synonym: Deflandrea (as Manumiella) druggii, according to Firth (1987, p.213) — however Thorn et al. (2009, p.443) retained Deflandrea (as Manumiella) druggii.
Holotype: Lange, 1969, pl.3, fig.3
Age: Danian
Original description (Lange, 1969) Not yet translated from German
Holotypus: Das im Praparat Nr. 11924/5 aufbewahrte und auf Tafel III, Figur 3 abgebildet Exemplar.
Locus typicus: Hojerup, Stevns-Klint (Seeland). Stratum typicum: Dan.
Diagnose: Der Panzer ist abgeflacht, sein UmriJ3 ist oval bis rautenformig. Die Epithek lauft in ein mehr oder weniger langes, am freien Ende abgestumpftes oder leicht zugespitztes Apikalhorn aus. Die großere Hypothek besitzt nur einen kleinen reduzierten Antapikalzipfel. Unter dem Apex liegt ein quadratisches bis rechteckiges, abgerundetes Pylom. Die Membran ist fein granuliert.
Zusatze: Eine sehr flach eingetene Querfurehe ist nur bei einigen Formen randlich zu beo bachten. Sie trennt die bedeutend· gr6Bere Hypothek von der fast rechtwinkligen Epithek. Von den anderen Arten der Gattung unterscheidet sich Broomea seelandica durch. den Umriß. des Korpers und die Ausbildung der Fortsatze.
Anzahl der Exemplare: 6.
MaBe des Holotypus: 106:71.
MaBe (Durchschnitt 6 Exempl.): 104:74.
Stratigraphische und regionale Verbreitung: Dan: Stevns-Klint (Seeland).
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Manumiella seelandica (Lange, 1969) Bujak and Davies, 1983, emend. Firth, 1987. Diagnosis for M.druggii. Outline of pericyst broadly elliptical, rarely elongate with a shallow antapical cavity which separates poorly developed antapical horns. Apical margin may be evenly rounded or a short, broadly-based, blunt apical horn may be present. Periphragm about 1 µm thick, and is smooth, scabrate or irregularly granulate with the sculptural features varying in diameter from ca 0.5 to 2 µm. Usually the coarser sculpturing is concentrated on the areas beyond the limits of the endocyst. Endocyst circular or nearly so in dorso-ventral view, commonly modified by folding. Endocyst not in contact with pericyst laterally. Operculum hinged antapically. Size: length 104-122 µm, width 92-103 µm.
Diagnosis for M.seelandica: The pericyst is flattened and oval to rhomboidal in outline. The epitheca ends in a more or less long apical horn which is truncate or lightly pointed at the free end. The hypocyst is larger and has only a small reduced antapical tip. The membrane is finely granulate. A very shallow cingulum is marginally noticeable in some specimens. Manumiella cretacea is much smaller than M.seelandica, which was considered a taxonomic senior synonym of M.druggii by Firth (1987, p.213). Size: 74-104 µm, holotype 71 µm wide.
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Emended Description: Firth 1987, p. 213-214
Medium to large bilayered, circumcavate (rarely bicavate) cyst. Pericyst roundly rhomboidal to elongate ovoidal. Epicyst and hypocyst roughly equal in size. Ambitus of epipericyst varies from broad and rounded (sometimes with blunt to concave apical end) to triangular with pointed apex. An apical protrusion may exist which varies from a knob 1-2 ,um high to a long, narrow acuminate horn greater than 30 Ám in length. Base of horn may be narrow and distinct, or may be broad and merge into cyst proper. Hypocyst shape like that of epicyst, except that antapical horn is shorter than apical horn, and that antapex may sometimes have two short, broadly rounded antapical horns with a medial concavity. Periphragm more or less coarsely granular, with apical and antapical poles often having larger and more densely distributed grana than the rest of cyst. Endocyst large, spherical-ovoidal to heart-shaped, often folded or flattened. Endophragm thin, laevigate. Paratabulation indicated only by deltaform intercalary archeo pyle (type Ia/Ia), and occasionally by a faint paracingulum and/or parasulcus.
Discussion. Considerable morphological variation was observed in a population of Manumiella cysts in the uppermost Cretaceous sample (sample 283.0) from the Albany Core. A gradation occurs between forms with a simple rounded-rhomboidal shape (identical to M. druggii) and those with more elongate, ovoidal cysts, bearing long apical and short antapical horns (identical with M. seelandica: see Plate 2, figs. 1-6). Wilson (1978) reported populations identical to that of the present study in upper Maastrichtian to lower Danian strata of New Zealand and Denmark. Though he observed a continuous gradient between the two end-member forms, Wilson still considered them to be separate species. The criterion for separating the two end-member forms into separate species (i.e., the presence or absence of any apical horn or protuberance) is an arbitrary one. The range of variability within M. seelandica (sensu Wilson), in which the apical horn length varies from 1 Ám to >30 Ám, far exceeds the difference between M. druggii (sensu Wilson) and M. seelandica (sensu Wilson; i.e., the difference between having no apical horn and having one of 1 Ám length). Furthermore, Stover (1973) reported the presence of small apical horns on some specimens from his type material, which would place those specimens within the species concept of M. seelandica. Wilson (1978) stated that the two species are virtually identical except for the presence or absence of an apical horn. Because of the occurrence of the complete spectrum of forms of this dinoflagellate throughout a restricted stratigraphic interval (upper Maastrichtian to lower Danian), Manumiella druggi is herein considered to be a junior synonym of Manumiella seelandica. This species has also been confused with a closely similar species, Manumiella cretacea (originally Deflandrea cretacea). Koch and Olssen (1977) attributed their specimens to this species, although their illustrated specimens (pl. 1, figs. 2, 3) more closely resemble M. seelandica. Stover (1973) observed that M. cretacea is much smaller and more completely bicavate than M. seelandica. Wilson (1978) discussed the past confusion regarding differentiation of these two species in detail.
Dimensions. Overall (pericyst) height 89.0-153.0 µm (mean 106.4 µm), overall (pericyst) width 75.0- 116.0 µm (mean 88.9 µm), endocyst height 49.0- 80.0 µm (mean 62.0 µm), endocyst width 63.0-96.0 µm (mean 75.6 µm), apical horn length 0.0-23.0 µm (mean 8.7 µm), antapical horn length 0.0-12.0 µm (mean 3.8 µm), Transverse Archeopyle Index 0.32- 0.46 (mean 0.38, n = 22). Total number of specimens measured = 25.
Synonyms: Firth 1987, p. 213
Broomea seelandica Lange, 1969, p. 113-114, pl. 2, fig. 10, pl. 3, fig. 3.
Deflandrea druggii Stover, 1973, p. 171, pl. 1, figs. 3a, b, 4.
Isabelia seelandica (Lange) Lentin & Williams, 1976, p. 58.
Isabelia druggii (Stover) Lentin & Williams, 1976, p. 58.
Isabelidinium seelandicum (Lange) Lentin & Williams, 1977, p. 168.
Isabelidinium druggii (Stover) Lentin & Williams, 1977, p. 168.
Manumiella seelandica (Lange) Bujak & Davies, 1983, p. 161, pl. 7, fig. 12.
Manumiella druggii (Stover) Bujak & Davies, 1983, p. 162.
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NOW Manumiella. Originally Broomea, subsequently Isabelia (combination illegitimate), thirdly Isabelidinium, fourthly (and now) Manumiella.
Taxonomic junior synonym: Deflandrea (as Manumiella) druggii, according to Firth (1987, p.213) — however Thorn et al. (2009, p.443) retained Deflandrea (as Manumiella) druggii.
Holotype: Lange, 1969, pl.3, fig.3
Age: Danian
Original description (Lange, 1969) Not yet translated from German
Holotypus: Das im Praparat Nr. 11924/5 aufbewahrte und auf Tafel III, Figur 3 abgebildet Exemplar.
Locus typicus: Hojerup, Stevns-Klint (Seeland). Stratum typicum: Dan.
Diagnose: Der Panzer ist abgeflacht, sein UmriJ3 ist oval bis rautenformig. Die Epithek lauft in ein mehr oder weniger langes, am freien Ende abgestumpftes oder leicht zugespitztes Apikalhorn aus. Die großere Hypothek besitzt nur einen kleinen reduzierten Antapikalzipfel. Unter dem Apex liegt ein quadratisches bis rechteckiges, abgerundetes Pylom. Die Membran ist fein granuliert.
Zusatze: Eine sehr flach eingetene Querfurehe ist nur bei einigen Formen randlich zu beo bachten. Sie trennt die bedeutend· gr6Bere Hypothek von der fast rechtwinkligen Epithek. Von den anderen Arten der Gattung unterscheidet sich Broomea seelandica durch. den Umriß. des Korpers und die Ausbildung der Fortsatze.
Anzahl der Exemplare: 6.
MaBe des Holotypus: 106:71.
MaBe (Durchschnitt 6 Exempl.): 104:74.
Stratigraphische und regionale Verbreitung: Dan: Stevns-Klint (Seeland).
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999
Manumiella seelandica (Lange, 1969) Bujak and Davies, 1983, emend. Firth, 1987. Diagnosis for M.druggii. Outline of pericyst broadly elliptical, rarely elongate with a shallow antapical cavity which separates poorly developed antapical horns. Apical margin may be evenly rounded or a short, broadly-based, blunt apical horn may be present. Periphragm about 1 µm thick, and is smooth, scabrate or irregularly granulate with the sculptural features varying in diameter from ca 0.5 to 2 µm. Usually the coarser sculpturing is concentrated on the areas beyond the limits of the endocyst. Endocyst circular or nearly so in dorso-ventral view, commonly modified by folding. Endocyst not in contact with pericyst laterally. Operculum hinged antapically. Size: length 104-122 µm, width 92-103 µm.
Diagnosis for M.seelandica: The pericyst is flattened and oval to rhomboidal in outline. The epitheca ends in a more or less long apical horn which is truncate or lightly pointed at the free end. The hypocyst is larger and has only a small reduced antapical tip. The membrane is finely granulate. A very shallow cingulum is marginally noticeable in some specimens. Manumiella cretacea is much smaller than M.seelandica, which was considered a taxonomic senior synonym of M.druggii by Firth (1987, p.213). Size: 74-104 µm, holotype 71 µm wide.
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Emended Description: Firth 1987, p. 213-214
Medium to large bilayered, circumcavate (rarely bicavate) cyst. Pericyst roundly rhomboidal to elongate ovoidal. Epicyst and hypocyst roughly equal in size. Ambitus of epipericyst varies from broad and rounded (sometimes with blunt to concave apical end) to triangular with pointed apex. An apical protrusion may exist which varies from a knob 1-2 ,um high to a long, narrow acuminate horn greater than 30 Ám in length. Base of horn may be narrow and distinct, or may be broad and merge into cyst proper. Hypocyst shape like that of epicyst, except that antapical horn is shorter than apical horn, and that antapex may sometimes have two short, broadly rounded antapical horns with a medial concavity. Periphragm more or less coarsely granular, with apical and antapical poles often having larger and more densely distributed grana than the rest of cyst. Endocyst large, spherical-ovoidal to heart-shaped, often folded or flattened. Endophragm thin, laevigate. Paratabulation indicated only by deltaform intercalary archeo pyle (type Ia/Ia), and occasionally by a faint paracingulum and/or parasulcus.
Discussion. Considerable morphological variation was observed in a population of Manumiella cysts in the uppermost Cretaceous sample (sample 283.0) from the Albany Core. A gradation occurs between forms with a simple rounded-rhomboidal shape (identical to M. druggii) and those with more elongate, ovoidal cysts, bearing long apical and short antapical horns (identical with M. seelandica: see Plate 2, figs. 1-6). Wilson (1978) reported populations identical to that of the present study in upper Maastrichtian to lower Danian strata of New Zealand and Denmark. Though he observed a continuous gradient between the two end-member forms, Wilson still considered them to be separate species. The criterion for separating the two end-member forms into separate species (i.e., the presence or absence of any apical horn or protuberance) is an arbitrary one. The range of variability within M. seelandica (sensu Wilson), in which the apical horn length varies from 1 Ám to >30 Ám, far exceeds the difference between M. druggii (sensu Wilson) and M. seelandica (sensu Wilson; i.e., the difference between having no apical horn and having one of 1 Ám length). Furthermore, Stover (1973) reported the presence of small apical horns on some specimens from his type material, which would place those specimens within the species concept of M. seelandica. Wilson (1978) stated that the two species are virtually identical except for the presence or absence of an apical horn. Because of the occurrence of the complete spectrum of forms of this dinoflagellate throughout a restricted stratigraphic interval (upper Maastrichtian to lower Danian), Manumiella druggi is herein considered to be a junior synonym of Manumiella seelandica. This species has also been confused with a closely similar species, Manumiella cretacea (originally Deflandrea cretacea). Koch and Olssen (1977) attributed their specimens to this species, although their illustrated specimens (pl. 1, figs. 2, 3) more closely resemble M. seelandica. Stover (1973) observed that M. cretacea is much smaller and more completely bicavate than M. seelandica. Wilson (1978) discussed the past confusion regarding differentiation of these two species in detail.
Dimensions. Overall (pericyst) height 89.0-153.0 µm (mean 106.4 µm), overall (pericyst) width 75.0- 116.0 µm (mean 88.9 µm), endocyst height 49.0- 80.0 µm (mean 62.0 µm), endocyst width 63.0-96.0 µm (mean 75.6 µm), apical horn length 0.0-23.0 µm (mean 8.7 µm), antapical horn length 0.0-12.0 µm (mean 3.8 µm), Transverse Archeopyle Index 0.32- 0.46 (mean 0.38, n = 22). Total number of specimens measured = 25.
Synonyms: Firth 1987, p. 213
Broomea seelandica Lange, 1969, p. 113-114, pl. 2, fig. 10, pl. 3, fig. 3.
Deflandrea druggii Stover, 1973, p. 171, pl. 1, figs. 3a, b, 4.
Isabelia seelandica (Lange) Lentin & Williams, 1976, p. 58.
Isabelia druggii (Stover) Lentin & Williams, 1976, p. 58.
Isabelidinium seelandicum (Lange) Lentin & Williams, 1977, p. 168.
Isabelidinium druggii (Stover) Lentin & Williams, 1977, p. 168.
Manumiella seelandica (Lange) Bujak & Davies, 1983, p. 161, pl. 7, fig. 12.
Manumiella druggii (Stover) Bujak & Davies, 1983, p. 162.
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