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Manumiella seelandica
From Fensome et al., 2019:
Manumiella seelandica (Lange, 1969, p.113–114, pl.2, fig.10; pl.3, fig.3) Bujak and Davies, 1983, p.162. Emendation: Firth, 1987, p.213–214, as Manumiella seelandica. Holotype: Lange, 1969, pl.3, fig.3; Fensome et al., 1995, fig.2 — p.1773. 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. Age: Danian.
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Original description (Lange, 1969) translation PKB 2025
Holotype: The specimen preserved in specimen no. 11924/5 and illustrated in Plate III, Figure 3.
Typical location: Hojerup, Stevns-Klint (Zealand). Typical stratum: Dan.
Diagnosis: The carapace is flattened, with an oval to diamond-shaped outline. The epitheca terminates in a more or less long apical horn, blunt or slightly pointed at the free end. The larger hypotheca has only a small, reduced antapical lobe. A square to rectangular, rounded pyloma lies beneath the apex. The membrane is finely granulated.
Notes: A very shallow transverse groove is only observed at the edges of some forms. It separates the significantly larger hypotheca from the almost rectangular epitheca. Broomea seelandica differs from the other species of the genus in its outline. of the body and the development of the processes.
Number of specimens: 6.
Dimensions of the holotype: 106:71.
Dimensions (average of 6 specimens): 104:74.
Stratigraphic and regional distribution: Dan: Stevns-Klint (Seeland).
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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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Supplemental discussion Thorn et al., 2009:
Discussion: Lange (1969) established this species as Broomea seelandica and described it as having an oval to rhombic outline, a finely granulate periphragm, and a square to rectangular archeopyle. The epicyst has a blunt to pointed apical protrusion; the distal tip is frequently surmounted by a small apical thickening. The larger hypocyst typically has a relatively small, distally-pointed left antapical horn and the right antapical horn is significantly reduced. Habib and Saeedi (2007) noted a characteristically ovoid endocyst with a flattened, rounded triangular apex, wider than it is high. In this study Manumiella seelandica occurs only in the uppermost López de Bertodano Formation (1025–949 m in the composite section), immediately underlying the KT boundary (Fig. 3). Cookson (1956, pl. 1, fig. 5) illustrated a specimen of Deflandrea cretacea; this has poorly-developed apical and antapical horns and Stover (1973) suggested that it is Manumiella druggii. However, this specimen corresponds more closely with Manumiella seelandica using the taxonomic key herein. Furthermore, specimens referred to Deflandrea cretacea from the Late Cretaceous of the New Jersey coastal plain (Koch and Olsson, 1977, figs. 3[2, 3]) are closer to Manumiella seelandica (sensu Lange) using the key. Similarly, Eshet et al. (1992, pl. III, fig. 3) illustrated a specimen with a distinct, short, distally-pointed antapical horn as Manumiella druggii. This specimen appears to be Manumiella seelandica. In a study of the Cretaceous–Palaeogene transition of Mead Stream, Marlborough, New Zealand, Strong et al. (1995, fig. 13.1) recorded both Manumiella druggii and Manumiella seelandica. These authors illustrated one specimen as Manumiella cf. seelandica, which appears to be conspecific with the type material.
Due to morphological continuities in the complex of forms between M. seelandica and M. druggii, individual specimens in previous studies have either been identified as one or other of these species. An example of this is Wilson (1978) who uses both the names Isabelia seelandica and Isabelia druggii. Other examples are specimens identified as Manumiella seelandica that encompass forms ranging between the two end-members of seelandica- and druggii-types (e.g. Stover, 1973; Fensome and Williams, 2004).
Bujak and Davies (1983) retained both Manumiella seelandica and Manumiella druggii within their new genus Manumiella, nominating Manumiella seelandica as the type species. Askin (1988a, figs. 9.7, 9.9) recognised both species. In the present study, recognition of key morphological distinctions aided by the new taxonomic key are considered sufficient and consistent enough to retain the two separate species.
Firth (1987) considered the range of variability within Manumiella seelandica (sensu Wilson, 1978) from the Maastrichtian and Danian of Georgia, U.S.A. to be greater than the variation between Manumiella seelandica and Manumiella druggii. Therefore Firth (1987) considered Manumiella seelandica to be a senior synonym of Manumiella druggii. Firth (1987, pl. 2, fig. 1) illustrated a specimen that would be classified herein as Manumiella druggii. The other specimens (Firth, 1987, pl. 2, figs. 2–6) are referable to Manumiella seelandica. Soncini and Rauscher (1990), Fensome and Williams (2004) and Habib and Saeedi (2007) also considered Manumiella seelandica to be a senior synonym of Manumiella druggii. The “Manumiella seelandica morphotype” of Habib and Saeedi (2007, pl. I, fig. 4; pl. II, figs. 1, 2, 4) was considered to be variant of Manumiella seelandica by these authors.
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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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Manumiella seelandica (Lange, 1969, p.113–114, pl.2, fig.10; pl.3, fig.3) Bujak and Davies, 1983, p.162. Emendation: Firth, 1987, p.213–214, as Manumiella seelandica. Holotype: Lange, 1969, pl.3, fig.3; Fensome et al., 1995, fig.2 — p.1773. 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. Age: Danian.
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Original description (Lange, 1969) translation PKB 2025
Holotype: The specimen preserved in specimen no. 11924/5 and illustrated in Plate III, Figure 3.
Typical location: Hojerup, Stevns-Klint (Zealand). Typical stratum: Dan.
Diagnosis: The carapace is flattened, with an oval to diamond-shaped outline. The epitheca terminates in a more or less long apical horn, blunt or slightly pointed at the free end. The larger hypotheca has only a small, reduced antapical lobe. A square to rectangular, rounded pyloma lies beneath the apex. The membrane is finely granulated.
Notes: A very shallow transverse groove is only observed at the edges of some forms. It separates the significantly larger hypotheca from the almost rectangular epitheca. Broomea seelandica differs from the other species of the genus in its outline. of the body and the development of the processes.
Number of specimens: 6.
Dimensions of the holotype: 106:71.
Dimensions (average of 6 specimens): 104:74.
Stratigraphic and regional distribution: Dan: Stevns-Klint (Seeland).
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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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Supplemental discussion Thorn et al., 2009:
Discussion: Lange (1969) established this species as Broomea seelandica and described it as having an oval to rhombic outline, a finely granulate periphragm, and a square to rectangular archeopyle. The epicyst has a blunt to pointed apical protrusion; the distal tip is frequently surmounted by a small apical thickening. The larger hypocyst typically has a relatively small, distally-pointed left antapical horn and the right antapical horn is significantly reduced. Habib and Saeedi (2007) noted a characteristically ovoid endocyst with a flattened, rounded triangular apex, wider than it is high. In this study Manumiella seelandica occurs only in the uppermost López de Bertodano Formation (1025–949 m in the composite section), immediately underlying the KT boundary (Fig. 3). Cookson (1956, pl. 1, fig. 5) illustrated a specimen of Deflandrea cretacea; this has poorly-developed apical and antapical horns and Stover (1973) suggested that it is Manumiella druggii. However, this specimen corresponds more closely with Manumiella seelandica using the taxonomic key herein. Furthermore, specimens referred to Deflandrea cretacea from the Late Cretaceous of the New Jersey coastal plain (Koch and Olsson, 1977, figs. 3[2, 3]) are closer to Manumiella seelandica (sensu Lange) using the key. Similarly, Eshet et al. (1992, pl. III, fig. 3) illustrated a specimen with a distinct, short, distally-pointed antapical horn as Manumiella druggii. This specimen appears to be Manumiella seelandica. In a study of the Cretaceous–Palaeogene transition of Mead Stream, Marlborough, New Zealand, Strong et al. (1995, fig. 13.1) recorded both Manumiella druggii and Manumiella seelandica. These authors illustrated one specimen as Manumiella cf. seelandica, which appears to be conspecific with the type material.
Due to morphological continuities in the complex of forms between M. seelandica and M. druggii, individual specimens in previous studies have either been identified as one or other of these species. An example of this is Wilson (1978) who uses both the names Isabelia seelandica and Isabelia druggii. Other examples are specimens identified as Manumiella seelandica that encompass forms ranging between the two end-members of seelandica- and druggii-types (e.g. Stover, 1973; Fensome and Williams, 2004).
Bujak and Davies (1983) retained both Manumiella seelandica and Manumiella druggii within their new genus Manumiella, nominating Manumiella seelandica as the type species. Askin (1988a, figs. 9.7, 9.9) recognised both species. In the present study, recognition of key morphological distinctions aided by the new taxonomic key are considered sufficient and consistent enough to retain the two separate species.
Firth (1987) considered the range of variability within Manumiella seelandica (sensu Wilson, 1978) from the Maastrichtian and Danian of Georgia, U.S.A. to be greater than the variation between Manumiella seelandica and Manumiella druggii. Therefore Firth (1987) considered Manumiella seelandica to be a senior synonym of Manumiella druggii. Firth (1987, pl. 2, fig. 1) illustrated a specimen that would be classified herein as Manumiella druggii. The other specimens (Firth, 1987, pl. 2, figs. 2–6) are referable to Manumiella seelandica. Soncini and Rauscher (1990), Fensome and Williams (2004) and Habib and Saeedi (2007) also considered Manumiella seelandica to be a senior synonym of Manumiella druggii. The “Manumiella seelandica morphotype” of Habib and Saeedi (2007, pl. I, fig. 4; pl. II, figs. 1, 2, 4) was considered to be variant of Manumiella seelandica by these authors.
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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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