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Lithodinia
From Fensome et al., 2019:
Lithodinia, Eisenack, 1935, p.175. Emendations: Gocht, 1975b, p.353; Williams et al., 1993, p.54.
Taxonomic junior synonym: Meiourogonyaulax, according to Gocht (1975b, p.353) and Williams et al. (1993, p.54) -- however, Meiourogonyaulax was retained by Riding and Helby (2001d, p.81,83).
Type: Eisenack, 1935, pl.4, fig.5, as Lithodinia jurassica.
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Original description: [Eisenack, 1935]: (Translation: Stover and Evitt, 1978, p. 60):
Description:
Cells generally polyhedral and in side view (dorsal or ventral) a rather elongated hexagon with more or less arched sides; more rarely spherical. Hypovalve equal or slightly higher than epivalve. Transverse furrow distinct, even when very shallow. Longitudinal furrow scarcely visible, apparently extremely shallow. Transverse section circular at the level of the girdle. Equatorial plates (in epi- and hypovalves) strikingly large and rounded trapezohedral. Only one antapical plate of square to trapezohedral outline. Apical and antapical plates completely flat lying, the latter parallel to the plane of the girdle. Plate boundaries (some of the apical pole excepted) marked by wing-like ridges, which may pass through all stages from very weak to conspicuously strong, from fine to coarse. When the wing-like ridges are strongly developed, only the edge against the hypovalve is provided with one. Occasionally (with the more weakly winged specimens) the protruberances are forked at their end.
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Emended description:
Gocht, 1975: (Translation: Stover and Evitt, 1978, p. 60-61):
Description:
Body ovoidal, spherical or polygonal. Reflected tabulation, according to the formula 4`, 6``, 0-7c, 5-7```, 0-2p, 0-1av, 0-1pv, 1````, usually well expressed. In the longitudinal furrow, other plates besides av and pv are indicated occasionally. Sutures in the form of ridges, crested ridges, septa or rows of low processes. Wall often (?always) two layered. Outer surface smooth, rough or furnished with projections or processes. Archaeopyle formation through release of the apical plates.
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Williams et al., 1993:
Synopsis:
Cysts proximate, subspherical to roundly polygonal: paratabulation gonyaulacacean, indicated by generally low, continuous or discontinuous parasutural features, formula: 4`, 6``, 0-6c, 5-6```, 1p, 1````, 0-1s, hypocystal pattern is standard sexiform; archeopyle apical, operculum tetraplacoid, contiguous or non-contiguous.
Description:
Shape: Subspherical to roundly polygonal.
Wall Relationships: Autophragm only; SEM analysis reveals two wall layers that are not discernible with light microscopic techniques.
Wall Features: Parasutural features consist of generally low continuous and smooth or perforate or striate and of essentially uniform height, or discontinuous projections; latter isolated or joined proximally. Areas between parasutural features smooth or with features of low relief.
Archeopvle: Apical; operculum tetraplacoid, contiguous or disarticulated, free.
Paratabulation: Gonyaulacacean, expressed by parasutural features; formula: 4`, 6``, 0-6c, 5-6```, lp, 1`````. 0-1 s. Presence of anterior intercalary paraplates unconfirmed; hypocystal pattern standard sexiform.
Paracingulum: Subdivided and represented by six subrectangular paraplates, or undivided.
Parasulcus: Anterior position indicated by shallow to deep parasulcal notch; delimited laterally and posteriorly by continuous or discontinuous parasutural features; faint indications of subdivision may be discernible.
Size: Small to intermediate.
Affinities:
Lithodinia differs from Lanterna Dodekova 1969 in having parasutural rather than pandasutural features and in lacking conspicuous ornamentation in the intratabular areas. Cernicysta Stover and Helby 1987 has a relatively large first postcingular paraplate, which is either absent or small on Lithodinia, and a middorsal hypocystal septum which Lithodinia lacks. Cerbia Below 1981 has penitabular features as well as a lenticular body with an offset parasulcal notch.
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Modified description:
Stover and Evitt, 1978, p. 61:
Synopsis:
Cysts proximate, subspherical to roundly polyhedral; paratabulation indicated by parasutural rows of of short projections whose bases may coalesce; gonyaulacacean, formula: 4`, 6``, 6c, 5```, 1p, 1````, 1 or more s; archaeopyle apical, Type 4A, typically with deep parasulcal notch.
Description:
Shape: Subspherical to subpolyhedral.
Wall relationships: Autophragm only; SEM reveals two wall layers that are not discernible with light microscopy.
Wall features: Low parasutural projections - some isolated, some joined proximally - indicate paraplate boundaries; areas between parasutural features roughened to irregularly punctoreticulate.
Paratabulation: Indicated by parasutural features, and generally less clearly expressed ventrally than dorsally; gonyaulacacean, formula: 4`, 6``, 6c, 5```, 1p, 1````, ?s.
Archaeopyle: apical, Type 4A; principal archaeopyle suture zigzag with deep parasulcal notch; opercular pieces free.
Paracingulum: Indicated by six subrectangular paraplates.
Parasulcus: Delimited laterally and antapically by discontinuous parasutural features and apically by base of parasulcal notch.
Size: Intermediate.
Affinities:
Lithodinia differs from Meiourogonyaulax in having a type 4A archaeopyle with free opercular pieces rather than a Type tA archaeopyle. In general, the parasutural features are more continuous and higher on Meiourogonyaulax than those on Lithodinia.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Lithodinia Eisenack, 1935, emend. Gocht, 1975b, emend. Williams et al., 1993. According to Williams et al. (1993, p.54), Lithodinia is a proximate cyst, subspherical to roundly polygonal; paratabulation gonyaulacacean, indicated by generally low, continuous or discontinuous parasutural features, formulae: 4`, 6", 0-6c, 5-6"\rquote , 1p, 1"'', 0-1s, hypocystal pattern is standard sexiform; archeopyle apical, operculum tetraplacoid, contiguous or non-contiguous.
Lithodinia, Eisenack, 1935, p.175. Emendations: Gocht, 1975b, p.353; Williams et al., 1993, p.54.
Taxonomic junior synonym: Meiourogonyaulax, according to Gocht (1975b, p.353) and Williams et al. (1993, p.54) -- however, Meiourogonyaulax was retained by Riding and Helby (2001d, p.81,83).
Type: Eisenack, 1935, pl.4, fig.5, as Lithodinia jurassica.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eisenack, 1935]: (Translation: Stover and Evitt, 1978, p. 60):
Description:
Cells generally polyhedral and in side view (dorsal or ventral) a rather elongated hexagon with more or less arched sides; more rarely spherical. Hypovalve equal or slightly higher than epivalve. Transverse furrow distinct, even when very shallow. Longitudinal furrow scarcely visible, apparently extremely shallow. Transverse section circular at the level of the girdle. Equatorial plates (in epi- and hypovalves) strikingly large and rounded trapezohedral. Only one antapical plate of square to trapezohedral outline. Apical and antapical plates completely flat lying, the latter parallel to the plane of the girdle. Plate boundaries (some of the apical pole excepted) marked by wing-like ridges, which may pass through all stages from very weak to conspicuously strong, from fine to coarse. When the wing-like ridges are strongly developed, only the edge against the hypovalve is provided with one. Occasionally (with the more weakly winged specimens) the protruberances are forked at their end.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Gocht, 1975: (Translation: Stover and Evitt, 1978, p. 60-61):
Description:
Body ovoidal, spherical or polygonal. Reflected tabulation, according to the formula 4`, 6``, 0-7c, 5-7```, 0-2p, 0-1av, 0-1pv, 1````, usually well expressed. In the longitudinal furrow, other plates besides av and pv are indicated occasionally. Sutures in the form of ridges, crested ridges, septa or rows of low processes. Wall often (?always) two layered. Outer surface smooth, rough or furnished with projections or processes. Archaeopyle formation through release of the apical plates.
--------------------------------------
Williams et al., 1993:
Synopsis:
Cysts proximate, subspherical to roundly polygonal: paratabulation gonyaulacacean, indicated by generally low, continuous or discontinuous parasutural features, formula: 4`, 6``, 0-6c, 5-6```, 1p, 1````, 0-1s, hypocystal pattern is standard sexiform; archeopyle apical, operculum tetraplacoid, contiguous or non-contiguous.
Description:
Shape: Subspherical to roundly polygonal.
Wall Relationships: Autophragm only; SEM analysis reveals two wall layers that are not discernible with light microscopic techniques.
Wall Features: Parasutural features consist of generally low continuous and smooth or perforate or striate and of essentially uniform height, or discontinuous projections; latter isolated or joined proximally. Areas between parasutural features smooth or with features of low relief.
Archeopvle: Apical; operculum tetraplacoid, contiguous or disarticulated, free.
Paratabulation: Gonyaulacacean, expressed by parasutural features; formula: 4`, 6``, 0-6c, 5-6```, lp, 1`````. 0-1 s. Presence of anterior intercalary paraplates unconfirmed; hypocystal pattern standard sexiform.
Paracingulum: Subdivided and represented by six subrectangular paraplates, or undivided.
Parasulcus: Anterior position indicated by shallow to deep parasulcal notch; delimited laterally and posteriorly by continuous or discontinuous parasutural features; faint indications of subdivision may be discernible.
Size: Small to intermediate.
Affinities:
Lithodinia differs from Lanterna Dodekova 1969 in having parasutural rather than pandasutural features and in lacking conspicuous ornamentation in the intratabular areas. Cernicysta Stover and Helby 1987 has a relatively large first postcingular paraplate, which is either absent or small on Lithodinia, and a middorsal hypocystal septum which Lithodinia lacks. Cerbia Below 1981 has penitabular features as well as a lenticular body with an offset parasulcal notch.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 61:
Synopsis:
Cysts proximate, subspherical to roundly polyhedral; paratabulation indicated by parasutural rows of of short projections whose bases may coalesce; gonyaulacacean, formula: 4`, 6``, 6c, 5```, 1p, 1````, 1 or more s; archaeopyle apical, Type 4A, typically with deep parasulcal notch.
Description:
Shape: Subspherical to subpolyhedral.
Wall relationships: Autophragm only; SEM reveals two wall layers that are not discernible with light microscopy.
Wall features: Low parasutural projections - some isolated, some joined proximally - indicate paraplate boundaries; areas between parasutural features roughened to irregularly punctoreticulate.
Paratabulation: Indicated by parasutural features, and generally less clearly expressed ventrally than dorsally; gonyaulacacean, formula: 4`, 6``, 6c, 5```, 1p, 1````, ?s.
Archaeopyle: apical, Type 4A; principal archaeopyle suture zigzag with deep parasulcal notch; opercular pieces free.
Paracingulum: Indicated by six subrectangular paraplates.
Parasulcus: Delimited laterally and antapically by discontinuous parasutural features and apically by base of parasulcal notch.
Size: Intermediate.
Affinities:
Lithodinia differs from Meiourogonyaulax in having a type 4A archaeopyle with free opercular pieces rather than a Type tA archaeopyle. In general, the parasutural features are more continuous and higher on Meiourogonyaulax than those on Lithodinia.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Lithodinia Eisenack, 1935, emend. Gocht, 1975b, emend. Williams et al., 1993. According to Williams et al. (1993, p.54), Lithodinia is a proximate cyst, subspherical to roundly polygonal; paratabulation gonyaulacacean, indicated by generally low, continuous or discontinuous parasutural features, formulae: 4`, 6", 0-6c, 5-6"\rquote , 1p, 1"'', 0-1s, hypocystal pattern is standard sexiform; archeopyle apical, operculum tetraplacoid, contiguous or non-contiguous.