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Australisphaera digitata
Australisphaera digitata, (Duxbury, 1983), Jain and Khowaja-Ateequzzaman, 1984
Now Vesperopsis. Originally Muderongia?, subsequently Australisphaera, thirdly (and now) Vesperopsis, fourthly ?Vesperopsis.
Holotype: Duxbury, 1983, pl.3, fig.15; text-fig.15
Locus typicus: Atherfield section, Isle of Wight, England
Stratum typicum: Late Aptian
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Original description as Muderongia? digitata: [Duxbury, 1983, p. 36]:
Diagnosis:
A very thin-walled, proximate dinoflagellate cyst species which is roughly pentagonal in outline and which bears a total of seven digitate projections representing five horns. There is a single apical horn, which is the broadest of all, two antapical horns, which are narrow and of approximately equal length and two lateral horn composed of two pairs of long, narrow, digitate projections with the paracingulum running between each pair. The lateral horns are similar in length to those at the antapex and the posterior element of each pair is usually slightly the longer.
The archeopyle is apical with the operculum usually remaining attached.
Dimensions:
Holotype: 87 x 67 µm
Complete specimens: 102 (93) 87 x 90 (81) 67 µm; Specimens measured: 7
Remarks:
This species is only tentatively assigned to Muderongia. The presence of digitate lateral horns, on digitation being present on either side of the parcingulum, is a feature atypical of Muderongia. Further, the very thin-walled nature of this species makes it difficult to discern whether one or two walls are present and, therefore to positively assign it to either Muderongia or Australisphaera Davey, 1978. Occasionally, some indication of an inner body is observed, but this may be due simply to folding of the very thin cyst.
Now Vesperopsis. Originally Muderongia?, subsequently Australisphaera, thirdly (and now) Vesperopsis, fourthly ?Vesperopsis.
Holotype: Duxbury, 1983, pl.3, fig.15; text-fig.15
Locus typicus: Atherfield section, Isle of Wight, England
Stratum typicum: Late Aptian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Muderongia? digitata: [Duxbury, 1983, p. 36]:
Diagnosis:
A very thin-walled, proximate dinoflagellate cyst species which is roughly pentagonal in outline and which bears a total of seven digitate projections representing five horns. There is a single apical horn, which is the broadest of all, two antapical horns, which are narrow and of approximately equal length and two lateral horn composed of two pairs of long, narrow, digitate projections with the paracingulum running between each pair. The lateral horns are similar in length to those at the antapex and the posterior element of each pair is usually slightly the longer.
The archeopyle is apical with the operculum usually remaining attached.
Dimensions:
Holotype: 87 x 67 µm
Complete specimens: 102 (93) 87 x 90 (81) 67 µm; Specimens measured: 7
Remarks:
This species is only tentatively assigned to Muderongia. The presence of digitate lateral horns, on digitation being present on either side of the parcingulum, is a feature atypical of Muderongia. Further, the very thin-walled nature of this species makes it difficult to discern whether one or two walls are present and, therefore to positively assign it to either Muderongia or Australisphaera Davey, 1978. Occasionally, some indication of an inner body is observed, but this may be due simply to folding of the very thin cyst.