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Aldorfia vectensis
Aldorfia vectensis, Duxbury, 1983
Holotype: Duxbury, 1983, pl.4, figs.3,7,10; Jan du Chene et al., 1986, pl.8, figs.6-9.
Locus typicus: Compton Bay section, Isle of Wight, England
Stratum typicum: Late Aptian
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Original description: [Duxbury, 1983, p. 39]:
Diagnosis:
A holocavate, gonyaulacacean dinoflagellate cyst species. The autocyst is spheroidal to ovoidal with a distinct, distally closed, apical projection. The ectophragm, which is finely punctate, is clearly separate from the autophragm and the resultant ectocoel is particularly pronounced at the apex, the antapex and in the paracingular area. A distinct, distally closed apical horn is always present which mirrors the apical projection of the autocyst. Narrow muri constituting a crude reticulum are present between the auto- and ectocyst.
The paracingulum is laevorotatory, is indicated by two parallel, low ridges with a depression between and is almost totally devoid of reticulation.
The parasulcus is clearly defined by a distinct ventral depression.
Paratabulation is faintly marked on the ectophragm surface by low ridges and the archeopyle is formed by detachment of paraplate 3".
Dimensions:
Holotype - 82 x 73 µm. Overall - 84 (78) 67 x 73 (67) 61 µm.
Affinities:
A. vectensis is similar in many respects to A. aldorfensis, the type species. It differs, however, in possessing a better developed, more sharply-tapering apical horn on the pericyst and in possessing a distinct apical protrusion on the endocyst which mirrors this. A. aldorfensis bears a short, blunt apical projection on the pericyst (typical of the Endocrinium galeritum group - see above) and the epicyst is broadly-rounded apically. Nevertheless, the similarity between A. vectensis and A. aldorfensis clearly demonstrates the morphological convergence which is possible in cysts of very different ages.
Holotype: Duxbury, 1983, pl.4, figs.3,7,10; Jan du Chene et al., 1986, pl.8, figs.6-9.
Locus typicus: Compton Bay section, Isle of Wight, England
Stratum typicum: Late Aptian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Duxbury, 1983, p. 39]:
Diagnosis:
A holocavate, gonyaulacacean dinoflagellate cyst species. The autocyst is spheroidal to ovoidal with a distinct, distally closed, apical projection. The ectophragm, which is finely punctate, is clearly separate from the autophragm and the resultant ectocoel is particularly pronounced at the apex, the antapex and in the paracingular area. A distinct, distally closed apical horn is always present which mirrors the apical projection of the autocyst. Narrow muri constituting a crude reticulum are present between the auto- and ectocyst.
The paracingulum is laevorotatory, is indicated by two parallel, low ridges with a depression between and is almost totally devoid of reticulation.
The parasulcus is clearly defined by a distinct ventral depression.
Paratabulation is faintly marked on the ectophragm surface by low ridges and the archeopyle is formed by detachment of paraplate 3".
Dimensions:
Holotype - 82 x 73 µm. Overall - 84 (78) 67 x 73 (67) 61 µm.
Affinities:
A. vectensis is similar in many respects to A. aldorfensis, the type species. It differs, however, in possessing a better developed, more sharply-tapering apical horn on the pericyst and in possessing a distinct apical protrusion on the endocyst which mirrors this. A. aldorfensis bears a short, blunt apical projection on the pericyst (typical of the Endocrinium galeritum group - see above) and the epicyst is broadly-rounded apically. Nevertheless, the similarity between A. vectensis and A. aldorfensis clearly demonstrates the morphological convergence which is possible in cysts of very different ages.