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Aquadulcum
From Williams et al., 2017:
[Aquaduculum, Harland and Sarjeant, 1970, p. 220-221
Acritarch genus.
Type species: Aquaduculum serpense, Harland and Sarjeant, 1970 (pl.21, figs.7–8; text-fig.5)]
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Original diagnosis: [Harland and Sarjeant, 1970]:
Diagnosis:
Peridinoid to sub-spherical proximate cysts bearing a dense ornamentation of very short spines or vermiculae. The cingulum and sulcus are clearly differentiated by lack of such ornament. Nature of archaeopyle uncertain, possibly in the form of a transapical slit; no clear opening is normally visible.
Affinities:
This new genus is characterized by its shape, the nature of its ornamentation, and the absence of a reflected tabulation. The genera Tenua and Cobricosphaeridium differ in that they develop a typical apical (A) archaeopyle and Xenicodinium in that it possesses a precingular archaeopyle. Diconodinium is characterized by its development of apical and antapical horns: the nature of its archaeopyle is uncertain. The cysts of the freshwater dinoflagellate Peridinium limbatum (recently described by Evitt and Wall, 1968) are cavate: the type of archaeopyle they exhibit, opening on a transapical suture, may possibly be comparable to that of Aquadulcum, but this remains to be confirmed. Palaeohystrichophora, which is similar in ornamentation to Aquadulcum, is likewise cavate.
[Aquaduculum, Harland and Sarjeant, 1970, p. 220-221
Acritarch genus.
Type species: Aquaduculum serpense, Harland and Sarjeant, 1970 (pl.21, figs.7–8; text-fig.5)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original diagnosis: [Harland and Sarjeant, 1970]:
Diagnosis:
Peridinoid to sub-spherical proximate cysts bearing a dense ornamentation of very short spines or vermiculae. The cingulum and sulcus are clearly differentiated by lack of such ornament. Nature of archaeopyle uncertain, possibly in the form of a transapical slit; no clear opening is normally visible.
Affinities:
This new genus is characterized by its shape, the nature of its ornamentation, and the absence of a reflected tabulation. The genera Tenua and Cobricosphaeridium differ in that they develop a typical apical (A) archaeopyle and Xenicodinium in that it possesses a precingular archaeopyle. Diconodinium is characterized by its development of apical and antapical horns: the nature of its archaeopyle is uncertain. The cysts of the freshwater dinoflagellate Peridinium limbatum (recently described by Evitt and Wall, 1968) are cavate: the type of archaeopyle they exhibit, opening on a transapical suture, may possibly be comparable to that of Aquadulcum, but this remains to be confirmed. Palaeohystrichophora, which is similar in ornamentation to Aquadulcum, is likewise cavate.