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Aptea almohadensis
From Fensome et al., 2019:
Aptea almohadensis, Below, 1984, p.635, pl.1, figs.5A–B,6–7.
Holotype: Below, 1984, pl.1, figs.5A–B; Fensome et al., 2019a, figs.15C–D.
NOW Pseudoceratium. NOW Circulodinium.
Originally Aptea, subsequently Pseudoceratium, thirdly (and now) Circulodinium.
Age: middle–late Aptian.
Locus typicus: Magazan Plateau, offshore NW Africa
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Original description: [Below, 1984, p. 635]:
Diagnosis:
Proximate, lenticular cyst, shape subsphaeroidal to asymmetrical; with a left antapical bulge and occasionally with a right lateral bulge in the region of the postcingular paraplate girdle. Apex rounded or with a narrow bulge.
Paratabulation presumably ceratiacean--not completely indicated: 4", 1""-6"", as, Xc, X""", Xs, X"""".
Archeopyle apical, with simple, free, asymmetrical operculum, type [4A[1"-4"]].
Autophragma of varying thickness, very finely reticulated, rarely smooth. Cyst ornamentation very sparse and in most cases without rules of orientation. Ornaments as low, solid, flattened, interconnected ledges, isolated short spines with distally acuminated or blunted ends, or simple cones forming tubercles. Sometimes these ornaments are arranged to pandasutural lines.
Description:
The cyst shape is highly variable because of the development of an apical, right lateral and an asymmetrically arranged antapical bulge. Specimens with an asymmetrical shape caused by the presence of a left antapical bulge and therefore typical of the genus Aptea are present, as well as cysts with a subsphaeroidal or sphaeroidal Outline typical of the genus Cyclonephelium. The additional development of a right lateral bulge shows the close connection of these specimens to individuals of the genus Pseudoceratium. Reconstruction of paratabulation is only indirectly possible for the epicyst by studying the archeopyle suture and breakages of opercula and archeopyle margin. There are four apical paraplates. 1" and 2" are compact and polygonal, whereas 3" and 4" are typically elongated and thus cause the very asymmetrical operculum shape. The precingular paraplate series is divided into six precingulars and the plate as. Paratabulation of the hypocyst is unknown. The sparse distribution of low ornaments such as spines or tubercles makes any consideration of penitabular alignment along parasutures impossible. Because of this pandasutural zones are also not developed. In few cases, ornamentation is absent.
Dimensions:
Holotype length (without apical calotte) 58 µm, breadth 60 µm, maximal height of ornaments 2 µm; other specimens: length 50-60 µm, breadth 60-75 µm, maximal height of ornaments 1-4 µm.
Affinities:
This new species is related to Aptea eisenackii (Davey, 1969) Davey and Verdier, 1974. The sparse cyst ornamentation characteristic of A. almohadensis is a result of the strong reduction of ornaments in A. eisenackii.
Aptea almohadensis, Below, 1984, p.635, pl.1, figs.5A–B,6–7.
Holotype: Below, 1984, pl.1, figs.5A–B; Fensome et al., 2019a, figs.15C–D.
NOW Pseudoceratium. NOW Circulodinium.
Originally Aptea, subsequently Pseudoceratium, thirdly (and now) Circulodinium.
Age: middle–late Aptian.
Locus typicus: Magazan Plateau, offshore NW Africa
---------------------------------------------------------------------------------------------------
Original description: [Below, 1984, p. 635]:
Diagnosis:
Proximate, lenticular cyst, shape subsphaeroidal to asymmetrical; with a left antapical bulge and occasionally with a right lateral bulge in the region of the postcingular paraplate girdle. Apex rounded or with a narrow bulge.
Paratabulation presumably ceratiacean--not completely indicated: 4", 1""-6"", as, Xc, X""", Xs, X"""".
Archeopyle apical, with simple, free, asymmetrical operculum, type [4A[1"-4"]].
Autophragma of varying thickness, very finely reticulated, rarely smooth. Cyst ornamentation very sparse and in most cases without rules of orientation. Ornaments as low, solid, flattened, interconnected ledges, isolated short spines with distally acuminated or blunted ends, or simple cones forming tubercles. Sometimes these ornaments are arranged to pandasutural lines.
Description:
The cyst shape is highly variable because of the development of an apical, right lateral and an asymmetrically arranged antapical bulge. Specimens with an asymmetrical shape caused by the presence of a left antapical bulge and therefore typical of the genus Aptea are present, as well as cysts with a subsphaeroidal or sphaeroidal Outline typical of the genus Cyclonephelium. The additional development of a right lateral bulge shows the close connection of these specimens to individuals of the genus Pseudoceratium. Reconstruction of paratabulation is only indirectly possible for the epicyst by studying the archeopyle suture and breakages of opercula and archeopyle margin. There are four apical paraplates. 1" and 2" are compact and polygonal, whereas 3" and 4" are typically elongated and thus cause the very asymmetrical operculum shape. The precingular paraplate series is divided into six precingulars and the plate as. Paratabulation of the hypocyst is unknown. The sparse distribution of low ornaments such as spines or tubercles makes any consideration of penitabular alignment along parasutures impossible. Because of this pandasutural zones are also not developed. In few cases, ornamentation is absent.
Dimensions:
Holotype length (without apical calotte) 58 µm, breadth 60 µm, maximal height of ornaments 2 µm; other specimens: length 50-60 µm, breadth 60-75 µm, maximal height of ornaments 1-4 µm.
Affinities:
This new species is related to Aptea eisenackii (Davey, 1969) Davey and Verdier, 1974. The sparse cyst ornamentation characteristic of A. almohadensis is a result of the strong reduction of ornaments in A. eisenackii.