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Achilleodinium
From Fensome et al., 2019:
Achilleodinium, Eaton, 1976, p.234.
Taxonomic senior synonym: Florentinia, according to Duxbury (1980, p.119), Below (1982c, p.7) and Duxbury (1983, p.46) -- however, Lentin and Williams (1981, p.1) and Lentin and Williams (1985, p.2) retained Achilleodinium.
Type: Eisenack, 1954b, pl.11, fig.18, as Hystrichosphaeridium biformoides.
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Original description: [Eaton, 1976]:
Diagnosis: Dinoflagellate cysts having a spherical or subspherical body bearing two types of intratabular processes; cylindrical processes, one per reflected plate area, hollow, circular to polygonal in cross-section, distally open or closed, variable in size; the larger processes occurring on the pre- and postcingular and antapical zones, the smaller on the apical zone. Slender processes, simple or bifurcate, distally open, restricted to the cingular and sulcal zones.
Reflected tabulation 4`, 6``, 6c, 5```, 1p, 1````;
archaeopyle precingular, formed by displacement of plate 3``.
Affinities:
Achilleodinium is similar to Hystrichokolpoma Klump, 1953 emend. Williams and Downie, 1966 and Florentinia Davey and Verdier, 1973 in both overall morphology and reflected tabulation. Hystrichokolpoma is distinguished by having an apical tetratabular archaeopyle. In Florentinia the archaeopyle is formed by displacement of precingular plate 3`` with breakage or displacement of the apical plates. In achilleodinium the archaeopyle is formed exclusively by displacement of plate 3``, and there is no breakage or displacement of the apical plates.
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Modified description:
Stover and Evitt 1978, p. 137-138:
Synopsis:
Cysts skolochorate, acavate,gonyaulacacean; body subspherical to ellipsoidal with hollow, distally open or closed intratabular and penitabular processes; intratabular processes in paracingulum, parasulcus, and apical series characteristically distinctly narrower than all (or nearly all) of the penitabular precingular and postcingular processes; archaeopyle precingular, type P.
Description:
Shape: Body subspherical to ellipsoidal.
Wall relationships: Cysts acavate,endophragm and periphragm appressed between processes.
Wall features: No parasutural features. Intratabular processes tubular, open or closed distally; paracingular, parasulcal, and apical processes characteristically narrower than those in the precingular and postcingular series, except for the sixth precingular and the first postcingular processes. Periphragm smooth or finely granular.
Paratabulation: Indicated by intratabular and penitabular processes; gonyaulacacean, process formula: 4`, 6``, 6c, 5```, 1p, 1````, 3-5s.
Archaeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by six or more narrow processes; individual paraplates represented by one or two slender, isolated processes, by single narrow, transversely elongate processes, or by combination thereof.
Parasulcus: Indicated by three to five narrow intratabular processes.
Size: Intermediate.
Affinities:
Achilleodinium differs from Hystrichokolpoma in having a precingular rather than an apical archaeopyle, and from Florentinia in having a precingular rather than a combination Type tA+P archaeopyle.
Achilleodinium, Eaton, 1976, p.234.
Taxonomic senior synonym: Florentinia, according to Duxbury (1980, p.119), Below (1982c, p.7) and Duxbury (1983, p.46) -- however, Lentin and Williams (1981, p.1) and Lentin and Williams (1985, p.2) retained Achilleodinium.
Type: Eisenack, 1954b, pl.11, fig.18, as Hystrichosphaeridium biformoides.
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Original description: [Eaton, 1976]:
Diagnosis: Dinoflagellate cysts having a spherical or subspherical body bearing two types of intratabular processes; cylindrical processes, one per reflected plate area, hollow, circular to polygonal in cross-section, distally open or closed, variable in size; the larger processes occurring on the pre- and postcingular and antapical zones, the smaller on the apical zone. Slender processes, simple or bifurcate, distally open, restricted to the cingular and sulcal zones.
Reflected tabulation 4`, 6``, 6c, 5```, 1p, 1````;
archaeopyle precingular, formed by displacement of plate 3``.
Affinities:
Achilleodinium is similar to Hystrichokolpoma Klump, 1953 emend. Williams and Downie, 1966 and Florentinia Davey and Verdier, 1973 in both overall morphology and reflected tabulation. Hystrichokolpoma is distinguished by having an apical tetratabular archaeopyle. In Florentinia the archaeopyle is formed by displacement of precingular plate 3`` with breakage or displacement of the apical plates. In achilleodinium the archaeopyle is formed exclusively by displacement of plate 3``, and there is no breakage or displacement of the apical plates.
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Modified description:
Stover and Evitt 1978, p. 137-138:
Synopsis:
Cysts skolochorate, acavate,gonyaulacacean; body subspherical to ellipsoidal with hollow, distally open or closed intratabular and penitabular processes; intratabular processes in paracingulum, parasulcus, and apical series characteristically distinctly narrower than all (or nearly all) of the penitabular precingular and postcingular processes; archaeopyle precingular, type P.
Description:
Shape: Body subspherical to ellipsoidal.
Wall relationships: Cysts acavate,endophragm and periphragm appressed between processes.
Wall features: No parasutural features. Intratabular processes tubular, open or closed distally; paracingular, parasulcal, and apical processes characteristically narrower than those in the precingular and postcingular series, except for the sixth precingular and the first postcingular processes. Periphragm smooth or finely granular.
Paratabulation: Indicated by intratabular and penitabular processes; gonyaulacacean, process formula: 4`, 6``, 6c, 5```, 1p, 1````, 3-5s.
Archaeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by six or more narrow processes; individual paraplates represented by one or two slender, isolated processes, by single narrow, transversely elongate processes, or by combination thereof.
Parasulcus: Indicated by three to five narrow intratabular processes.
Size: Intermediate.
Affinities:
Achilleodinium differs from Hystrichokolpoma in having a precingular rather than an apical archaeopyle, and from Florentinia in having a precingular rather than a combination Type tA+P archaeopyle.