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Hystrichosphaeropsis
From Williams et al., 2017:
[Hystrichosphaeropsis, Deflandre, 1935, p. 232; Emendations: Sarjeant, 1966b, p. 138; Gocht, 1976, p. 331–333; Sarjeant, 1982b, p. 47.
Tax. sen. syn.: Triblastula, according to Yun Hyesu (1981, p.22) — however, Jan du Chêne et al. (1986a, p.158) retained Hystrichosphaeropsis.
Tax. jun. syn.: Rottnestia, according to Sarjeant (1966b, p.139) — however, Jan du Chêne et al. (1986a, p.309) retained Rottnestia.
Type species: Hytrichosphaeropsis ovum, Deflandre, 1935 (pl.8, fig.1)]
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Original description: [Deflandre, 1935]: (Translation: Stover and Evitt, 1978, p. 163):
Diagnosis:
The new genus Hystrichosphaeropsis, represented by a species, H. ovum, of which the diverse polar aliform expansions strongly recall those of Hystrichosphaera wetzelii Defl., seems to be very close to those of Hystrichosphaera. In Hystrichosphaeropsis, on the contrary, I have seen neither well defined plates, which can be counted and discriminated to establish a tabulation, nor an equatorial arrangement evoking a furrow. There are, however, in this equatorial region of Hystrichosphaeropsis a few short, forked, aligned processes, as well as a tendency of the membranous polar expansions to terminate there in a bend.
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Emended description:
Sarjeant, 1966:
Diagnosis:
Bicavate dinoflagellate cysts, pericoel divided by broad median zone of contact with inner body. Outline typically somewhat angular, apical and antapical pericoels typically quadrate in outline; apical horn arising from former.
Tabulation ?3-4`, ?1a, 6``, 6c, 6```, 1p, 1````, determinable on periphragm; sutures in form of ridges of varied height and ornamentation; simple or furcate spines of varied length arising from some or all crest nodes. Surface of endophragm and periphragm smooth, granular, punctate, nodose or reticulate.
Precingular archaeopyle formed by loss of plate 3``.
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Gocht, 1976: (Translation: LPP)
Diagnosis:
Cavate dinoflagellate cysts with elongate outer shell, without long processes, apically pointed, antapically rounded or blunt. Pre- and postcingular fields dorsally and laterally lengthened, delimited by strong folds or ridges. Girdle slightly helicoid, consisting of diamond-shaped fields. Margins of the equatorial girdle, as well as those of the ventral and polar fields, may be inconspicuous or completely suppressed. Ridges between the girdle-fields often stretched into short, carved projections. Inner body spherical to oval, forming a more or less broad zone of contact with the outer shell.
Precingular archaeopyle.
Reflected tabulation: 4`, 6``, 6c, 5-6```, 1````, 1p, 0-ns.
Remark:
Gocht, 1976, p. 331-332, was not able to study the type material (Hystrichosphaeropsis ovum), and consequently, his "emendation" of the genus was established from the comparison of figures and text.
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Sarjeant, 1982:
Diagnosis:
Proximate dinoflagellate cysts of intermediate to large size, elongate- subpolygonal in ambitus. Bicavate, with the central portion of the cyst bulging out beyond the lateral limits of the two pericoels. Epipericoel hemihexagonal to quadrate, prolonged into an apical horn of variable length; hypopericoel quadrate, terminated by a large antapical paraplate. Sutures completely or incompletely marked by lines or low ridges; at their positions of confluence, short gonal spines may arise (especially in the equatorial region and about the antapex).
Paratabulation 0-?2pa, 4`, 0-?2a, 6``, X or 5-6c, 5-6```, 1p, 1````; complete paratabulation rarely expressed and sulcus typically (consistently?) undivided. When visible, paraplate 4` is elongate and has only a short boundary with 6``; the latter paraplate varies in shape from almost quadrate to triangular, with convex, straight or concave sides. The boundary between 4` and 6`` intersects the right lateral boundary of 1` in a position somewhat, or markedly, anterior to the junction of the latter paraplate with the sulcus. Antapex penetrated by an opisthopyle, typically (consistently?) of much smaller size than that paraplate. Surface of endoblast and periblast typically smooth or only lightly ornamented with granules or punctae.
Archaeopyle single-plate precingular, formed by the loss of paraplate 3``; operculum reduced.
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Modified description:
Stover and Evitt 1978, p. 163-164:
Synopsis:
Cysts bicavate to circumcavate, elongate ellipsoidal with an apical horn; endocyst subspherical to ellipsoidal; periphragm close to or appressed to endocyst in paracingular and adjacent areas, typically more widely separated elsewhere; paratabulation gonyaulacacean, indicated with varying degrees of clarity by smooth parasutural ridges; archeopyle precingular, Type P.
Description:
Shape: Elongate ellipsoidal with a rounded to truncated antapex and a usually angular apex or an apical horn.
Wall relationships: Cysts bicavate to circumcavate; endocyst subspherical to ellipsoidal; periphragm close to or appressed to endophragm in paracingular and adjacent areas.
Wall features: Low smooth parasutural ridges on all or part of periphragm; periphragm between parasutural ridges smooth or ornamented with features of low relief.
Paratabulation: Indicated mainly by parasutural ridges; gonyaulacacean, formula: 3-4`, 1a?, 6``, Xc or 5-6c, 5-6```, 1p, 1````; complete paratabulation rarely expressed.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by five or six subrectangular paraplates or by transverse parallel ridges.
Parasulcus: Vaguely to clearly delimited by parasutural ridges.
Size: Intermediate to large.
Affinities:
Hystrichosphaeropsis differs from Psaligonyaulax in having smooth rather than denticulate ridges and from Rottnestia in lacking gonal processes.
[Hystrichosphaeropsis, Deflandre, 1935, p. 232; Emendations: Sarjeant, 1966b, p. 138; Gocht, 1976, p. 331–333; Sarjeant, 1982b, p. 47.
Tax. sen. syn.: Triblastula, according to Yun Hyesu (1981, p.22) — however, Jan du Chêne et al. (1986a, p.158) retained Hystrichosphaeropsis.
Tax. jun. syn.: Rottnestia, according to Sarjeant (1966b, p.139) — however, Jan du Chêne et al. (1986a, p.309) retained Rottnestia.
Type species: Hytrichosphaeropsis ovum, Deflandre, 1935 (pl.8, fig.1)]
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Original description: [Deflandre, 1935]: (Translation: Stover and Evitt, 1978, p. 163):
Diagnosis:
The new genus Hystrichosphaeropsis, represented by a species, H. ovum, of which the diverse polar aliform expansions strongly recall those of Hystrichosphaera wetzelii Defl., seems to be very close to those of Hystrichosphaera. In Hystrichosphaeropsis, on the contrary, I have seen neither well defined plates, which can be counted and discriminated to establish a tabulation, nor an equatorial arrangement evoking a furrow. There are, however, in this equatorial region of Hystrichosphaeropsis a few short, forked, aligned processes, as well as a tendency of the membranous polar expansions to terminate there in a bend.
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Emended description:
Sarjeant, 1966:
Diagnosis:
Bicavate dinoflagellate cysts, pericoel divided by broad median zone of contact with inner body. Outline typically somewhat angular, apical and antapical pericoels typically quadrate in outline; apical horn arising from former.
Tabulation ?3-4`, ?1a, 6``, 6c, 6```, 1p, 1````, determinable on periphragm; sutures in form of ridges of varied height and ornamentation; simple or furcate spines of varied length arising from some or all crest nodes. Surface of endophragm and periphragm smooth, granular, punctate, nodose or reticulate.
Precingular archaeopyle formed by loss of plate 3``.
--------------------------------
Gocht, 1976: (Translation: LPP)
Diagnosis:
Cavate dinoflagellate cysts with elongate outer shell, without long processes, apically pointed, antapically rounded or blunt. Pre- and postcingular fields dorsally and laterally lengthened, delimited by strong folds or ridges. Girdle slightly helicoid, consisting of diamond-shaped fields. Margins of the equatorial girdle, as well as those of the ventral and polar fields, may be inconspicuous or completely suppressed. Ridges between the girdle-fields often stretched into short, carved projections. Inner body spherical to oval, forming a more or less broad zone of contact with the outer shell.
Precingular archaeopyle.
Reflected tabulation: 4`, 6``, 6c, 5-6```, 1````, 1p, 0-ns.
Remark:
Gocht, 1976, p. 331-332, was not able to study the type material (Hystrichosphaeropsis ovum), and consequently, his "emendation" of the genus was established from the comparison of figures and text.
--------------------------------
Sarjeant, 1982:
Diagnosis:
Proximate dinoflagellate cysts of intermediate to large size, elongate- subpolygonal in ambitus. Bicavate, with the central portion of the cyst bulging out beyond the lateral limits of the two pericoels. Epipericoel hemihexagonal to quadrate, prolonged into an apical horn of variable length; hypopericoel quadrate, terminated by a large antapical paraplate. Sutures completely or incompletely marked by lines or low ridges; at their positions of confluence, short gonal spines may arise (especially in the equatorial region and about the antapex).
Paratabulation 0-?2pa, 4`, 0-?2a, 6``, X or 5-6c, 5-6```, 1p, 1````; complete paratabulation rarely expressed and sulcus typically (consistently?) undivided. When visible, paraplate 4` is elongate and has only a short boundary with 6``; the latter paraplate varies in shape from almost quadrate to triangular, with convex, straight or concave sides. The boundary between 4` and 6`` intersects the right lateral boundary of 1` in a position somewhat, or markedly, anterior to the junction of the latter paraplate with the sulcus. Antapex penetrated by an opisthopyle, typically (consistently?) of much smaller size than that paraplate. Surface of endoblast and periblast typically smooth or only lightly ornamented with granules or punctae.
Archaeopyle single-plate precingular, formed by the loss of paraplate 3``; operculum reduced.
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Modified description:
Stover and Evitt 1978, p. 163-164:
Synopsis:
Cysts bicavate to circumcavate, elongate ellipsoidal with an apical horn; endocyst subspherical to ellipsoidal; periphragm close to or appressed to endocyst in paracingular and adjacent areas, typically more widely separated elsewhere; paratabulation gonyaulacacean, indicated with varying degrees of clarity by smooth parasutural ridges; archeopyle precingular, Type P.
Description:
Shape: Elongate ellipsoidal with a rounded to truncated antapex and a usually angular apex or an apical horn.
Wall relationships: Cysts bicavate to circumcavate; endocyst subspherical to ellipsoidal; periphragm close to or appressed to endophragm in paracingular and adjacent areas.
Wall features: Low smooth parasutural ridges on all or part of periphragm; periphragm between parasutural ridges smooth or ornamented with features of low relief.
Paratabulation: Indicated mainly by parasutural ridges; gonyaulacacean, formula: 3-4`, 1a?, 6``, Xc or 5-6c, 5-6```, 1p, 1````; complete paratabulation rarely expressed.
Archeopyle: Precingular, Type P (3`` only); operculum free.
Paracingulum: Indicated by five or six subrectangular paraplates or by transverse parallel ridges.
Parasulcus: Vaguely to clearly delimited by parasutural ridges.
Size: Intermediate to large.
Affinities:
Hystrichosphaeropsis differs from Psaligonyaulax in having smooth rather than denticulate ridges and from Rottnestia in lacking gonal processes.