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Atopodinium perforatum
Atopodinium perforatum, (Clarke and Verdier, 1967), Masure, 1991; Emendations: as Pterodinium perforatum: Davey and Verdier, 1971, p.30, ; as Maghrebinia perforata: Below, 1981a, p. 23-24; Masure, 1988a, p. 363-364,
Originally Dinopterygium, subsequently Pterodinium, thirdly Pterodinium?, fourthly Maghrebinia, fifthly (and now) Atopodinium. Below, 1981, and Masure, 1988, emended the diagnosis of this species, as Maghrebinia perforata.
Holotype: Clarke and Verdier, 1967, pl.6, figs.1-2; Masure, 1988a, pl.1, figs.1-9; text-figs.1a-b; Fensome et al., 1995, figs.1-2 - p.1653; Fauconnier and Masure, 2004, pl.10, figs.5-6.
Locus typicus: Southern Cliff, Isle of Wight, England
Stratum typicum: Cenomanian
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Original description as Dinopterygium perforatum: [Clarke and Verdier, 1967, p. 37]:
Diagnosis:
A species of Dinopterygium with an indistinct girdle marked on the outline by two protrusions, and ledges which are perforate.
Description:
The epitheca is smaller than the hypotheca. Sides of epitheca straight; a small horn is sometimes observed at the apex. Sides of hypotheca straight; antapex rounded. Girdle indicated on outline only by the presence of two protrusions (pl. 6, fig. 2). Tabulation present, distinct and similar in arrangement to that of Scriniodinium. Plates bordered by high ledges 6-12 µm high, sculptured by perforations of various sizes. The form of the ledges is irregular, sometimes being high and entire, but often there is a development of processes of irregular width and height, generally perforated and with expanded tops. In this latter case the processes join at their bases to form low perforate ledges. The plates are mostly smooth except for a small perforated area adjacent to the ledges. No definite archaeopyle has so far been observed.
Dimensions/Measurements: Holotype - Range
Length: 66 µm 60-90 µm
Breadth: 71 µm 60-84 µm
Height of ledges (max.): 11µm 6-12 µm
Affinities:
D. perforatum differs from D. cladoides in the presence of perforated ledges, and the absence of verrucae on the plates.
Originally Dinopterygium, subsequently Pterodinium, thirdly Pterodinium?, fourthly Maghrebinia, fifthly (and now) Atopodinium. Below, 1981, and Masure, 1988, emended the diagnosis of this species, as Maghrebinia perforata.
Holotype: Clarke and Verdier, 1967, pl.6, figs.1-2; Masure, 1988a, pl.1, figs.1-9; text-figs.1a-b; Fensome et al., 1995, figs.1-2 - p.1653; Fauconnier and Masure, 2004, pl.10, figs.5-6.
Locus typicus: Southern Cliff, Isle of Wight, England
Stratum typicum: Cenomanian
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Original description as Dinopterygium perforatum: [Clarke and Verdier, 1967, p. 37]:
Diagnosis:
A species of Dinopterygium with an indistinct girdle marked on the outline by two protrusions, and ledges which are perforate.
Description:
The epitheca is smaller than the hypotheca. Sides of epitheca straight; a small horn is sometimes observed at the apex. Sides of hypotheca straight; antapex rounded. Girdle indicated on outline only by the presence of two protrusions (pl. 6, fig. 2). Tabulation present, distinct and similar in arrangement to that of Scriniodinium. Plates bordered by high ledges 6-12 µm high, sculptured by perforations of various sizes. The form of the ledges is irregular, sometimes being high and entire, but often there is a development of processes of irregular width and height, generally perforated and with expanded tops. In this latter case the processes join at their bases to form low perforate ledges. The plates are mostly smooth except for a small perforated area adjacent to the ledges. No definite archaeopyle has so far been observed.
Dimensions/Measurements: Holotype - Range
Length: 66 µm 60-90 µm
Breadth: 71 µm 60-84 µm
Height of ledges (max.): 11µm 6-12 µm
Affinities:
D. perforatum differs from D. cladoides in the presence of perforated ledges, and the absence of verrucae on the plates.