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Scriniodinium obscurum
Scriniodinium? obscurum Manum and Cookson, 1964
NOW Endoscrinium. Originally Scriniodinium, subsequently Scriniodinium?, thirdly (and now) Endoscrinium.
Stover and Evitt, 1978 considered this to be a "provisionally accepted species" of Scriniodinium.
Holotype: Manum and Cookson, 1964, pl.4, fig.6
Locus typicus: Graham Island, Arctic Canada
Stratum typicum: Late Cretaceous
Original description: Manum and Cookson, 1964, p. 21-22
Theca roughly quadrangular in outline, with a short, broad, and blunt apical projection, divided by an indistinct, equatorial girdle which is best seen as broad prominences at the lateral margins. The theca contains a large capsule of circular outline. The theca-membrane and the wall of the capsule are separated by a space of varying width, in some places they are closely opposed, in others, particularly at the apex and antapex, and the equator, widely separated.
The theca-membrane is very thin, indistinctly dotted, and much folded. There are no distinct connections running between the capsule and the theca, but fine, irregular lines, the true nature of which is obscured by the many folds, may possibly represent supporting fibrils. The wall of the capsule is up to 1 µm thick and sometimes indistinctly dotted. A large precingular archeopyle has been observed.
Dimensions: Holotype: 137 x 117 µm. Range: length 122-137 µm, width 104-124 µm.
Affinities:
Manum and Cookson, 1964, p. 21: Scriniodinium obscurum has been a constantly recurring form in the Graham Island preparations. Most of the specimes are Iying sideways but the few seen in dorsoventral view seem to come closest to S. playfordi Cookson and Eisenack (1960) from the Upper Jurassic of Western Australia. However, S. obscurum appears to be distinct from that species in its wider and more folded theca-membrane, the variation in the width of the space separating the theca from the capsule, the more circular outline of the capsule and its lack of a distinct surface pattern.
NOW Endoscrinium. Originally Scriniodinium, subsequently Scriniodinium?, thirdly (and now) Endoscrinium.
Stover and Evitt, 1978 considered this to be a "provisionally accepted species" of Scriniodinium.
Holotype: Manum and Cookson, 1964, pl.4, fig.6
Locus typicus: Graham Island, Arctic Canada
Stratum typicum: Late Cretaceous
Original description: Manum and Cookson, 1964, p. 21-22
Theca roughly quadrangular in outline, with a short, broad, and blunt apical projection, divided by an indistinct, equatorial girdle which is best seen as broad prominences at the lateral margins. The theca contains a large capsule of circular outline. The theca-membrane and the wall of the capsule are separated by a space of varying width, in some places they are closely opposed, in others, particularly at the apex and antapex, and the equator, widely separated.
The theca-membrane is very thin, indistinctly dotted, and much folded. There are no distinct connections running between the capsule and the theca, but fine, irregular lines, the true nature of which is obscured by the many folds, may possibly represent supporting fibrils. The wall of the capsule is up to 1 µm thick and sometimes indistinctly dotted. A large precingular archeopyle has been observed.
Dimensions: Holotype: 137 x 117 µm. Range: length 122-137 µm, width 104-124 µm.
Affinities:
Manum and Cookson, 1964, p. 21: Scriniodinium obscurum has been a constantly recurring form in the Graham Island preparations. Most of the specimes are Iying sideways but the few seen in dorsoventral view seem to come closest to S. playfordi Cookson and Eisenack (1960) from the Upper Jurassic of Western Australia. However, S. obscurum appears to be distinct from that species in its wider and more folded theca-membrane, the variation in the width of the space separating the theca from the capsule, the more circular outline of the capsule and its lack of a distinct surface pattern.