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Laticavodinium
From Williams et al., 2017:
[Laticavodinium, Wilson and Sarjeant, 1984c, p. 127
Type species: originally as Hystrichosphaeridium oligacanthum, Wetzel, 1952 (pl.A, fig.8)] ; Laticavodinium oligacanthum, Wilson and Sarjeant in Sarjeant, 1984
(Islam (1993, p.86) questionably transferred the "type species", Laticavodinium oligacanthum, to Impletosphaeridium)
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Original description: [Wilson and Sarjeant, 1984]:
Description:
Proximochorate to chorate, spiniferate cysts, holotabulate to hercotabulate, with the paratabulation 4`, 6", 6c, 5-?6```, 1p, 1``````(sic - remark LPP: should be 1````); sulcus typically undivided. Ambitus spheroidal to ovoidal or subpolygonal. Boundaries between paraplates marked by lines or crests of variable height, or unmarked. Gonal processes consistently, intergonal processes frequently, developed. Processes always closed distally but of variable relative length, thickness and distal form. The phragma surface may show small scale ornamentation, but intratabular or penitabular processes or crests are lacking. An apical protuberance may be developed.
Archaeopyle two-plate precingular (type 2P), formed by loss of the second and third precingular paraplates.
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Modified description:
Stover and Williams, 1987, p. 145:
Description/Discussion:
Wilson and Sarjeant in Sarjeant (1984b, p. 127) interpreted the single specimen (bid, pl. 2, figs. 4-5; text-fig. 2) assigned to the monotypic genus, Laticavodinium, as having a 2P (2"+3") archeopyle. With such an archeopyle, the shape of the opening should approximate that outlined by the solid lines in Figure 53B. A comparison of this outline to the archeopyle margin of L. oligacanthum - as drawn by Wilson and Sarjeant (Figure 53A) - shows that the line segment e-f in the anticipated model is lacking in Figure 53A. Apparently, no anteriorly camerate precingular paraplate is involved in the archeopyle formation of Laticavodinium. If Wilson and Sarjeant`s interpretation is correct, the two precingular paraplates released during archeopyle formation are not only anteriorly planate but are also adjacent. This relationship is unusual. In gonyaulacacean cysts in which the paratabulation is reasonably well determined, anteriorly planate precingular paraplates are always separated by one or more anteriorly camerate paraplates. We believe that the archeopyle of Laticavodinium can be interpreted alternatively as apical, type [tA] (Figure 53C). Following this interpretation, paraplate 3" is anteriorly camerate (normal for this paraplate), and the view of the holotype becomes oblique-dorsal rather than apical as indicated by Wilson and Sarjeant. Our interpretation is enhanced somewhat by noting that the short, concave segment of paraplate 1````, which indicates the posterior position of the parasulcus is situated on the ventral surface.
If the archeopyle was precingular, the parasulcus should be on the opposite surface. We regard Laticavodinium as a junior synonym of Cleistosphaeridium Davey et al. 1966. However, we do not refute the existence of forms for which the circumscription of Laticavodinium is appropriate-such as the Campanian specimens reported by Wilson in his Ph.D. thesis. Evidently the form selected as the type species is not one of them.
[Laticavodinium, Wilson and Sarjeant, 1984c, p. 127
Type species: originally as Hystrichosphaeridium oligacanthum, Wetzel, 1952 (pl.A, fig.8)] ; Laticavodinium oligacanthum, Wilson and Sarjeant in Sarjeant, 1984
(Islam (1993, p.86) questionably transferred the "type species", Laticavodinium oligacanthum, to Impletosphaeridium)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Wilson and Sarjeant, 1984]:
Description:
Proximochorate to chorate, spiniferate cysts, holotabulate to hercotabulate, with the paratabulation 4`, 6", 6c, 5-?6```, 1p, 1``````(sic - remark LPP: should be 1````); sulcus typically undivided. Ambitus spheroidal to ovoidal or subpolygonal. Boundaries between paraplates marked by lines or crests of variable height, or unmarked. Gonal processes consistently, intergonal processes frequently, developed. Processes always closed distally but of variable relative length, thickness and distal form. The phragma surface may show small scale ornamentation, but intratabular or penitabular processes or crests are lacking. An apical protuberance may be developed.
Archaeopyle two-plate precingular (type 2P), formed by loss of the second and third precingular paraplates.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 145:
Description/Discussion:
Wilson and Sarjeant in Sarjeant (1984b, p. 127) interpreted the single specimen (bid, pl. 2, figs. 4-5; text-fig. 2) assigned to the monotypic genus, Laticavodinium, as having a 2P (2"+3") archeopyle. With such an archeopyle, the shape of the opening should approximate that outlined by the solid lines in Figure 53B. A comparison of this outline to the archeopyle margin of L. oligacanthum - as drawn by Wilson and Sarjeant (Figure 53A) - shows that the line segment e-f in the anticipated model is lacking in Figure 53A. Apparently, no anteriorly camerate precingular paraplate is involved in the archeopyle formation of Laticavodinium. If Wilson and Sarjeant`s interpretation is correct, the two precingular paraplates released during archeopyle formation are not only anteriorly planate but are also adjacent. This relationship is unusual. In gonyaulacacean cysts in which the paratabulation is reasonably well determined, anteriorly planate precingular paraplates are always separated by one or more anteriorly camerate paraplates. We believe that the archeopyle of Laticavodinium can be interpreted alternatively as apical, type [tA] (Figure 53C). Following this interpretation, paraplate 3" is anteriorly camerate (normal for this paraplate), and the view of the holotype becomes oblique-dorsal rather than apical as indicated by Wilson and Sarjeant. Our interpretation is enhanced somewhat by noting that the short, concave segment of paraplate 1````, which indicates the posterior position of the parasulcus is situated on the ventral surface.
If the archeopyle was precingular, the parasulcus should be on the opposite surface. We regard Laticavodinium as a junior synonym of Cleistosphaeridium Davey et al. 1966. However, we do not refute the existence of forms for which the circumscription of Laticavodinium is appropriate-such as the Campanian specimens reported by Wilson in his Ph.D. thesis. Evidently the form selected as the type species is not one of them.