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Svalbardella cooksoniae
Svalbardella cooksoniae Manum, 1960
Holotype: Manum 1960, pl. 1, figs. 1-3, text-fig. 2
Locus typicus: Sarsbukta, Vestspitsbergen, Spitsbergen, Norway
Stratum typicum: Late Paleocene-Eocene
Original diagnosis: Manum, 1960, p. 21
Theca fusiform with its middle part somewhat convex; length 150-172 µm. Girdle nearly equatorial, shallow, with a break on the ventral face. A "longitudinal furrow" starts between the ends of the girdle and runs to the end of the hypotheca. Theca-membrane minutily reticulate, in profile finely undulate. The convex part of the theca is entirely filled by an internal body of ellipsoid shape with smooth and thin wall.
Original description: Manum, 1960, p. 21
All specimens obtained (10) have and internal body which dorsally, towards its apical end, has a somewhat angular opening; at the corresponding place in the theca there is a similar and usually longer opening whose lower borderline coincides with that of the opening of the body. The internal body entirely fills the theca in the equatorial region, but its wall is distinct from the theca-membrane along the lateral outline. The girdle is usually easily observable, but its edges are only slightly noticeable in the outline of the theca. The holotype clearly shows the ends of the girdle on the ventral side. What appears to be a longitudinal furrow is found in most specimens on close examination, but is less distinct than the girdle. The details at the starting point of the furrow are not clear. The membrane has indistinct lines suggestive of plates. Some specimens are recognizable by their shape only, the fine ornamentation and other details not having been preserved.
Affinities:
Manum, 1960, p. 21: The presence of a girdle and most probably of a longitudinal furrow and of plates establish the inclusion of this fossil in the dinoflagellates. Its shape somewhat recalls the genus Centrodinium and some species of Murayella (M. biconica and M. intermedia), but as there are only indications of the plates it cannot be more closely compared with any of these recent genera. I know of no fossils with which to compare this species. There is a superfluous resemblance to some specimens figured by Wetzel and Deflandre and Cookson but otherwise they are not comparable. As in Deflandrea phosphoritica the internal body has a fixed position inside the theca, and the openings are very similar. Evidently the internal body is of the same nature in the two organisms.
Holotype: Manum 1960, pl. 1, figs. 1-3, text-fig. 2
Locus typicus: Sarsbukta, Vestspitsbergen, Spitsbergen, Norway
Stratum typicum: Late Paleocene-Eocene
Original diagnosis: Manum, 1960, p. 21
Theca fusiform with its middle part somewhat convex; length 150-172 µm. Girdle nearly equatorial, shallow, with a break on the ventral face. A "longitudinal furrow" starts between the ends of the girdle and runs to the end of the hypotheca. Theca-membrane minutily reticulate, in profile finely undulate. The convex part of the theca is entirely filled by an internal body of ellipsoid shape with smooth and thin wall.
Original description: Manum, 1960, p. 21
All specimens obtained (10) have and internal body which dorsally, towards its apical end, has a somewhat angular opening; at the corresponding place in the theca there is a similar and usually longer opening whose lower borderline coincides with that of the opening of the body. The internal body entirely fills the theca in the equatorial region, but its wall is distinct from the theca-membrane along the lateral outline. The girdle is usually easily observable, but its edges are only slightly noticeable in the outline of the theca. The holotype clearly shows the ends of the girdle on the ventral side. What appears to be a longitudinal furrow is found in most specimens on close examination, but is less distinct than the girdle. The details at the starting point of the furrow are not clear. The membrane has indistinct lines suggestive of plates. Some specimens are recognizable by their shape only, the fine ornamentation and other details not having been preserved.
Affinities:
Manum, 1960, p. 21: The presence of a girdle and most probably of a longitudinal furrow and of plates establish the inclusion of this fossil in the dinoflagellates. Its shape somewhat recalls the genus Centrodinium and some species of Murayella (M. biconica and M. intermedia), but as there are only indications of the plates it cannot be more closely compared with any of these recent genera. I know of no fossils with which to compare this species. There is a superfluous resemblance to some specimens figured by Wetzel and Deflandre and Cookson but otherwise they are not comparable. As in Deflandrea phosphoritica the internal body has a fixed position inside the theca, and the openings are very similar. Evidently the internal body is of the same nature in the two organisms.