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Psaligonyaulax
From Williams et al., 2017:
[Psaligonyaulax, Sarjeant, 1966b, p. 136: Emendation: Sarjeant, 1982b, p. 44–45.
Tax. sr. syn.: Gonyaulacysta, according to Below (1981a, p.52) — however, Lentin and Williams (1981, p.235) retained Psaligonyaulax.
Type species: Psaligonyaulax deflandrei, Sarjeant, 1966b (pl.14, figs.7–8; text-fig.35)] ; emend. Sarjeant, 1982
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Original description: [Sarjeant, 1966]:
Description:
Bicavate dinoflagellate cysts, pericoel separated into two portions by broad median zone of contact with inner body. Outline spheroidal to ellipsoidal or subpolygonal with apical horn. Tabulation 3-4`, 1a, 6``, 6c, 6```, 1p, 1```` determinable on periphragm, sutures in form of ridges of varied height and ornament. No spines arise from crest nodes. Surface of endophragm and periphragm smooth, granular, nodose, reticulate or punctate. Precingular archaeopyle formed by loss of plate3``.
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Modified description:
Stover and Evitt, 1978, p. 182:
Synopsis:
Cysts proximate, bicavate, elongate ellipsoidal with a normally short apical horn; endocyst subspherical, endophragm and periphragm appressed in paracingular and adjacent areas; paratabulation gonyaulacacean, indicated by denticulate parasutural ridges or septa; gonal projections or processes absent; archeopyle precingular, Type P.
Description:
Shape: Elongate ellipsoidal with a normally short apical horn.
Wall relationships: Cysts bicavate, endocyst subspherical; periphragm and endophragm appressed in paracingular and adjacent areas.
Wall features: Parasutural ridges or septa with denticulate crests. Periphragm between parasutural features smooth or faintly ornamented .
Paratabulation. Indicated by parasutural features; gonyaulacacean, formula: 3-4`, 1a, 6``, X-6c, 6```, 1p, 1````.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by six rectangular paraplates.
Parasulcus: Not indicated, or expressed as a narrow, longitudinally elongate area bordered by parasutural ridges or septa.
Size: Intermediate.
Affinities:
Psaligonyaulax differs from Hystrichosphaeropsis in having parasutural ridges or septa with denticulate crests, whereas the parasutural ridges on Hystrichosphaeropsis are smooth; and from Gonyaulacysta in having larger pericoels. Psaligonyaulax appears to be one end-member of a series of forms with denticulate crests characterized by variable development of apical and antapical pericoels. Other members of the series are currently referred to Gonyaulacysta.
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Emended description:
Sarjeant, 1982:
Description:
Proximate dinoflagellate cysts, ellipsoidal to spindle-shaped or elongate subpolygonal in ambitus, with apex acute (or prolonged into an apical horn) and antapex truncate or rounded. Bicavate, with epipericoel and hypopericoel of variable relative proportions and with the hypopericoel arising smoothly, or only at a slight angle, from the anterior part of the hypotract. Endoblast spheroidal to broadly ovoidal. Parasutures clearly marked on the periblast by raised ridges or crests which may be smooth or denticulate to serrate or echinate distally.
Paratabulation ?1pa, 4`, 1-2a, 6", 6c, 6```, 1p, 0-?1pv, 1````. Paraplate 4` is elongate, as long as or longer than 1` and having only a short boundary with 6". The latter paraplate is triangular in shape, with convex, straight or concave sides. The boundary between 4` and 6" makes direct contact with the right lateral boundary of the sulcus.
Surface of periphragm between crests smooth to granular, with or without an irregular scatter of tubercles. No opisthopyle is developed. Archaeopyle single-plate precingular, formed by loss of paraplate 3".
Affinities:
Indeed, in its complete reflection of the gonyaulacoid paratabulation pattern, with even such tiny paraplates as the preapicals and dorsal anterior intercalaries reflected, Psaligonyaulax is so strikingly like Gonyaulacysta that a direct derivation from that genus, rather than from the superficially similar but less clearly tabulate Tubotuberella, appears in the highest degree probable. (Psaligonyaulax further differs from Tubotuberella in the more elaborate development of its crests, in the lack of an opisthopyle, and in its development of tubercles). I would suggest, therefore, that there have been two lineages, not one, arising from the Gonyaulacysta stock, in each of which cavation developed at both poles. The genera Hystrichosphaeropsis and Rottnestia may belong to this second lineage; but it seems to me more probable that they are derivatives from the Spiniferites stock. In placing those genera into the Family Spiniferitaceae, I am for the moment accepting the latter hypothesis.
[Psaligonyaulax, Sarjeant, 1966b, p. 136: Emendation: Sarjeant, 1982b, p. 44–45.
Tax. sr. syn.: Gonyaulacysta, according to Below (1981a, p.52) — however, Lentin and Williams (1981, p.235) retained Psaligonyaulax.
Type species: Psaligonyaulax deflandrei, Sarjeant, 1966b (pl.14, figs.7–8; text-fig.35)] ; emend. Sarjeant, 1982
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Sarjeant, 1966]:
Description:
Bicavate dinoflagellate cysts, pericoel separated into two portions by broad median zone of contact with inner body. Outline spheroidal to ellipsoidal or subpolygonal with apical horn. Tabulation 3-4`, 1a, 6``, 6c, 6```, 1p, 1```` determinable on periphragm, sutures in form of ridges of varied height and ornament. No spines arise from crest nodes. Surface of endophragm and periphragm smooth, granular, nodose, reticulate or punctate. Precingular archaeopyle formed by loss of plate3``.
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Modified description:
Stover and Evitt, 1978, p. 182:
Synopsis:
Cysts proximate, bicavate, elongate ellipsoidal with a normally short apical horn; endocyst subspherical, endophragm and periphragm appressed in paracingular and adjacent areas; paratabulation gonyaulacacean, indicated by denticulate parasutural ridges or septa; gonal projections or processes absent; archeopyle precingular, Type P.
Description:
Shape: Elongate ellipsoidal with a normally short apical horn.
Wall relationships: Cysts bicavate, endocyst subspherical; periphragm and endophragm appressed in paracingular and adjacent areas.
Wall features: Parasutural ridges or septa with denticulate crests. Periphragm between parasutural features smooth or faintly ornamented .
Paratabulation. Indicated by parasutural features; gonyaulacacean, formula: 3-4`, 1a, 6``, X-6c, 6```, 1p, 1````.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by six rectangular paraplates.
Parasulcus: Not indicated, or expressed as a narrow, longitudinally elongate area bordered by parasutural ridges or septa.
Size: Intermediate.
Affinities:
Psaligonyaulax differs from Hystrichosphaeropsis in having parasutural ridges or septa with denticulate crests, whereas the parasutural ridges on Hystrichosphaeropsis are smooth; and from Gonyaulacysta in having larger pericoels. Psaligonyaulax appears to be one end-member of a series of forms with denticulate crests characterized by variable development of apical and antapical pericoels. Other members of the series are currently referred to Gonyaulacysta.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Sarjeant, 1982:
Description:
Proximate dinoflagellate cysts, ellipsoidal to spindle-shaped or elongate subpolygonal in ambitus, with apex acute (or prolonged into an apical horn) and antapex truncate or rounded. Bicavate, with epipericoel and hypopericoel of variable relative proportions and with the hypopericoel arising smoothly, or only at a slight angle, from the anterior part of the hypotract. Endoblast spheroidal to broadly ovoidal. Parasutures clearly marked on the periblast by raised ridges or crests which may be smooth or denticulate to serrate or echinate distally.
Paratabulation ?1pa, 4`, 1-2a, 6", 6c, 6```, 1p, 0-?1pv, 1````. Paraplate 4` is elongate, as long as or longer than 1` and having only a short boundary with 6". The latter paraplate is triangular in shape, with convex, straight or concave sides. The boundary between 4` and 6" makes direct contact with the right lateral boundary of the sulcus.
Surface of periphragm between crests smooth to granular, with or without an irregular scatter of tubercles. No opisthopyle is developed. Archaeopyle single-plate precingular, formed by loss of paraplate 3".
Affinities:
Indeed, in its complete reflection of the gonyaulacoid paratabulation pattern, with even such tiny paraplates as the preapicals and dorsal anterior intercalaries reflected, Psaligonyaulax is so strikingly like Gonyaulacysta that a direct derivation from that genus, rather than from the superficially similar but less clearly tabulate Tubotuberella, appears in the highest degree probable. (Psaligonyaulax further differs from Tubotuberella in the more elaborate development of its crests, in the lack of an opisthopyle, and in its development of tubercles). I would suggest, therefore, that there have been two lineages, not one, arising from the Gonyaulacysta stock, in each of which cavation developed at both poles. The genera Hystrichosphaeropsis and Rottnestia may belong to this second lineage; but it seems to me more probable that they are derivatives from the Spiniferites stock. In placing those genera into the Family Spiniferitaceae, I am for the moment accepting the latter hypothesis.