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Doidyx
From Williams et al., 2017:
[Doidyx, Sarjeant, 1966c, p. 205-206
Type species: Doidyx anaphrissa, Sarjeant, 1966c (pl.22, fig.8; text-fig.55)]
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Original description: [Sarjeant, 1966]:
Diagnosis:
Proximate dinoflagellate cysts with flattened biconical shell, pronouncedly asymmetrical. Epitract in form of high cone which may be drawn out into an apical horn, giving a mammillate appearance: hypotract in form of flattened cone, with or without antapical prominence. Shell bulging out laterally to one side more than to the other; lateral horns lacking. Greater part of shell surface covered with short spines, simple or bifurcate: arrangement is in general random, but sometimes in rows, suggesting traces of tabulation. Equatorial zone, corresponding to cingulum, lacking spines: not hollowed. No pattern of sutures visible, no clear indication of sulcus. Apical archaeopyle formed by schism of shell on angular line of breakage.
Affinities:
In its asymmetrically biconical shell, spine cover and absence of tabulation, this new genus differs from all described fossil genera. The asymmetry and mode of archaeopyle formation suggests a probable derivation from the genus Pseudoceratium by reduction of polar horns and loss of the lateral horn. Doidyx differs from Diconodinium, Palaeohystrichophora and Dioxya in its asymmetrical shape: from Diconodinium also in the absence of a sulcus: from Palaeohystrichophora also in the lack of an inner body; and from Dioxya in the clear indication of a cingulum. It differs from the superficially similar genus Aptea in the lack of an enclosing membrane.
[Doidyx, Sarjeant, 1966c, p. 205-206
Type species: Doidyx anaphrissa, Sarjeant, 1966c (pl.22, fig.8; text-fig.55)]
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Original description: [Sarjeant, 1966]:
Diagnosis:
Proximate dinoflagellate cysts with flattened biconical shell, pronouncedly asymmetrical. Epitract in form of high cone which may be drawn out into an apical horn, giving a mammillate appearance: hypotract in form of flattened cone, with or without antapical prominence. Shell bulging out laterally to one side more than to the other; lateral horns lacking. Greater part of shell surface covered with short spines, simple or bifurcate: arrangement is in general random, but sometimes in rows, suggesting traces of tabulation. Equatorial zone, corresponding to cingulum, lacking spines: not hollowed. No pattern of sutures visible, no clear indication of sulcus. Apical archaeopyle formed by schism of shell on angular line of breakage.
Affinities:
In its asymmetrically biconical shell, spine cover and absence of tabulation, this new genus differs from all described fossil genera. The asymmetry and mode of archaeopyle formation suggests a probable derivation from the genus Pseudoceratium by reduction of polar horns and loss of the lateral horn. Doidyx differs from Diconodinium, Palaeohystrichophora and Dioxya in its asymmetrical shape: from Diconodinium also in the absence of a sulcus: from Palaeohystrichophora also in the lack of an inner body; and from Dioxya in the clear indication of a cingulum. It differs from the superficially similar genus Aptea in the lack of an enclosing membrane.