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Andalusiella rhomboides
From Fensome et al., 2019:
Andalusiella rhomboides, (Boltenhagen, 1977, p.106–107, pl.20, figs.1a–b,2a–b,3) Lentin and Williams, 1980, p.41.
Emendation: Masure et al., 1996, p.182, as Andalusiella rhomboides.
Holotype: Boltenhagen, 1977, pl.20, figs.1a–b.
Originally Svalbardella, subsequently (and now) Andalusiella.
Age: Campanian.
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Original description: [Boltenhagen, 1977] (translated from French):
Svalbardella rhomboïdes nov. sp.
Pointe-Clairette Series, Carnpan ien: Port-Gent il (Gabon, Equatorial Africa).
DIAGNOSIS
Theca with a lozenge-shaped outline, elongated along the polar axis and provided above the poles with two short, thick horns; thecal membrane covered by microspines; circular and narrow cingulate dividing the theca into two equal parts; sulcus located on half of the hypotheca; subtrapezoidal-hexagonal archaeopyle; smooth capsule adhering to the thecal walls.
DESCRIPTION
This species is characterized by a lozenge-shaped theca with two short, thick, ogival-shaped horns. The microspines, approximately 0.5 to 1 μ, completely cover the theca, and their spacing is of the order of their size. This microsculpture is more or less pronounced, depending on the specimen considered and at 320 magnification appears as a microgranulation or a punctuation. The smooth capsule is almost adherent to the theca and is only clearly visible below the bases of the horns where it is rounded. The horns are ornamented by a few microspines. The rather narrow cingulum is hardly perceptible, masked by transverse folds, but laterally it is manifested by slight notches. The bottom of the cingulum seems to be devoid of ornamentation. The sulcus, according to the holotype, is widely open towards the cingulum and extends approximately halfway along the hypotheca. The open archaeopyle was not observed. However, the sutures of the operculum clearly show its position and shape. It is located below the apex, its outline is subtrapezoidal with angles of the large truncated base, in other words its outline is hexagonal, analogous to that of the genus Deflandrea.
DIMENSIONS
Holotype: theca (with horns): L = 120 μ or more
(without horns): L' x l = 105 x 82 μ
capsule: L'' x l = 104 x 79 μ
horns: h' - h'' = 10-12u (folded)
inf. archaeopyle base = 29 μ - sup. base = 9 μ
sup. sides = 23 μ; inf. sides = 7-11 μ
cingulum: l = 5-6 μ
Paratypes (incomplete specimens):
theca (with horns): L' = 147 μ or + (apic. horn torn off, antap. horn developed) and 126 μ or +
(without horns): L'' = 120 and 111 μ
l' = more than 96 μ and more than 80 μ
capsule: L'' = 115 and 117 μ
horns: h' - h'' - h''' = 13-15-20 μ
COMPARISON
This species is distinguished from the generotype Svalbardella cooksoniae MAN. 1960 (pp. 2 1·22, in text fig. 2, PI. I, Fig. 1-3) by the angular shape of its theca, its short horns, and its microsculpture. In terms of its silhouette, the described species is very reminiscent of Diconodintum glabrum EIS. and COOK. 1960 (p. 3, PI. I, Fig. 11), which lacks the capsule, which is its distinctive feature.
Stratigraphic and Geographic Position
Upper Cretaceous: Campanian; Gabon (Port-Gentil).
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Emended diagnosis:
Masure, Tea and Yao 1996, p. 182:
Diagnosis:
Proximate, acrocavate or cornucavate dinoflagellate cyst with rhomboidal to ovoidal central body, one apical horn and only one antapical horn. Wall composed of a verrucose periphragm and verrucose endophragm. The periphragm on distal end of horns may be verrucose or smooth. Brown or colorless endophragm.
Peridinoid paratabulation indicated by the archeopyle, paracingulum slightly descending (Evitt, 1985), levorotatory bordered by folds and continuous verruca, parasulcus with bean-shaped flagellar scar.
Intercalary archeopyle of I/I type, standard 2a hexa, isodeltaforme, operculum free, occasionally adherent.
Remark:
Svalbardella sp. A, sp. B and sp. D are considered as specimens of the population of Svalbardella rhomboides. These specimens have ovoidal central bodies and longer apical and antapical horns than the holotype of Andalusiella rhomboides. The horns of the latter are transversally folded, so they seem shorter than they really are. All specimens are coming from hole CL 42, and Svalbardella sp. A is located in the same slide as the holotype of Andalusiella rhomboide.
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Andalusiella rhomboides, (Boltenhagen, 1977, p.106–107, pl.20, figs.1a–b,2a–b,3) Lentin and Williams, 1980, p.41.
Emendation: Masure et al., 1996, p.182, as Andalusiella rhomboides.
Holotype: Boltenhagen, 1977, pl.20, figs.1a–b.
Originally Svalbardella, subsequently (and now) Andalusiella.
Age: Campanian.
---------------------------------------------------------------------------------------------------
Original description: [Boltenhagen, 1977] (translated from French):
Svalbardella rhomboïdes nov. sp.
Pointe-Clairette Series, Carnpan ien: Port-Gent il (Gabon, Equatorial Africa).
DIAGNOSIS
Theca with a lozenge-shaped outline, elongated along the polar axis and provided above the poles with two short, thick horns; thecal membrane covered by microspines; circular and narrow cingulate dividing the theca into two equal parts; sulcus located on half of the hypotheca; subtrapezoidal-hexagonal archaeopyle; smooth capsule adhering to the thecal walls.
DESCRIPTION
This species is characterized by a lozenge-shaped theca with two short, thick, ogival-shaped horns. The microspines, approximately 0.5 to 1 μ, completely cover the theca, and their spacing is of the order of their size. This microsculpture is more or less pronounced, depending on the specimen considered and at 320 magnification appears as a microgranulation or a punctuation. The smooth capsule is almost adherent to the theca and is only clearly visible below the bases of the horns where it is rounded. The horns are ornamented by a few microspines. The rather narrow cingulum is hardly perceptible, masked by transverse folds, but laterally it is manifested by slight notches. The bottom of the cingulum seems to be devoid of ornamentation. The sulcus, according to the holotype, is widely open towards the cingulum and extends approximately halfway along the hypotheca. The open archaeopyle was not observed. However, the sutures of the operculum clearly show its position and shape. It is located below the apex, its outline is subtrapezoidal with angles of the large truncated base, in other words its outline is hexagonal, analogous to that of the genus Deflandrea.
DIMENSIONS
Holotype: theca (with horns): L = 120 μ or more
(without horns): L' x l = 105 x 82 μ
capsule: L'' x l = 104 x 79 μ
horns: h' - h'' = 10-12u (folded)
inf. archaeopyle base = 29 μ - sup. base = 9 μ
sup. sides = 23 μ; inf. sides = 7-11 μ
cingulum: l = 5-6 μ
Paratypes (incomplete specimens):
theca (with horns): L' = 147 μ or + (apic. horn torn off, antap. horn developed) and 126 μ or +
(without horns): L'' = 120 and 111 μ
l' = more than 96 μ and more than 80 μ
capsule: L'' = 115 and 117 μ
horns: h' - h'' - h''' = 13-15-20 μ
COMPARISON
This species is distinguished from the generotype Svalbardella cooksoniae MAN. 1960 (pp. 2 1·22, in text fig. 2, PI. I, Fig. 1-3) by the angular shape of its theca, its short horns, and its microsculpture. In terms of its silhouette, the described species is very reminiscent of Diconodintum glabrum EIS. and COOK. 1960 (p. 3, PI. I, Fig. 11), which lacks the capsule, which is its distinctive feature.
Stratigraphic and Geographic Position
Upper Cretaceous: Campanian; Gabon (Port-Gentil).
---------------------------------------------------------------------------------------------------
Emended diagnosis:
Masure, Tea and Yao 1996, p. 182:
Diagnosis:
Proximate, acrocavate or cornucavate dinoflagellate cyst with rhomboidal to ovoidal central body, one apical horn and only one antapical horn. Wall composed of a verrucose periphragm and verrucose endophragm. The periphragm on distal end of horns may be verrucose or smooth. Brown or colorless endophragm.
Peridinoid paratabulation indicated by the archeopyle, paracingulum slightly descending (Evitt, 1985), levorotatory bordered by folds and continuous verruca, parasulcus with bean-shaped flagellar scar.
Intercalary archeopyle of I/I type, standard 2a hexa, isodeltaforme, operculum free, occasionally adherent.
Remark:
Svalbardella sp. A, sp. B and sp. D are considered as specimens of the population of Svalbardella rhomboides. These specimens have ovoidal central bodies and longer apical and antapical horns than the holotype of Andalusiella rhomboides. The horns of the latter are transversally folded, so they seem shorter than they really are. All specimens are coming from hole CL 42, and Svalbardella sp. A is located in the same slide as the holotype of Andalusiella rhomboide.
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