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Cerbia
From Fensome et al., 2019:
Cerbia, Below, 1981a, p.8.
Taxonomic senior synonym: Tenua Eisenack, according to Sarjeant (1985a, p.93–94; 1992b, p.678) -- however, Duxbury (2002, p.76,78) retained Cerbia.
Type: Davey and Verdier, 1974, pl.92, figs.1,4, as Cyclonephelium tabulatum.
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Original Description: [Below, 1981]: (Translation: Fensome 1991, p. 123)
Diagnosis:
Proximate to proximochorate, lenticular cyst with a single-layered wall. Round-oval or roundish pentagonal in outline. Apex rounded or with a slight bulge. Antapex rounded or with a lobe and two bulges. Membrane smooth or sculptured.
Paratabulation 4`, 6", Xc, 6```, pc, 1````, Xs. Fields delimited by penitabular ornament, intratabular appendages absent.
Archeopyle apical, (A).
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Modified description:
Stover and Williams, 1987, p.55:
Synopsis:
Cysts proximate to proximochorate, lenticular, may be lobate antapically; paratabulation of 4`, 6", Xc, 5-6```, 1p, 1```` and Os indicated by the arrangement of short penitabular processes or tubercles on the autocyst; archeopyle apical type (4A), operculum free- parasulcal notch offset.
Descrpition:
Shape: Lenticular; apical margin obtusely angular,
antapical margin with a single left lobe or bulge or with two lobes or bulges of similar size separated by a relatively shallow median concavity.
Wall relationships: Autophragm only.
Wall features: Basically smooth or faintly sculptured, autophragm ornamented with penitabular tubercules or short processes.
Archeopyle: Apical type [4A], operculum free.
Paratabulation: Indicated by archeopyle and penitabular features; formula: 4`, 6", Xc, 5-6```,1 p, 1```` and 0s; first postcingular paraplate not always delineated.
Paracingulum: Expressed by parallel, transverse rows of tubercles or short processes; undivided; amount of ventral offset varies from virtually none to about twice the longitudinal dimension of the paracingulum.
Parasulcus: Indicated by shallow sigmoidal depression extending posteriorly from the offset parasulcal notch.
Size: Intermediate; length about 80 µm to 95 µm.
Affinities:
Cerbia differs from Canninginopsis Cookson and Eisenack 1962b in having the paratabulation expressed by penitabular rather than parasutural features. On Cyclonephelium Deflandre and Cookson 1955 emended Stover and Evitt 1978, the ornamentation is nontabular and more or less confined to the peripheral areas, but not necessarily so. Cysts of Canningia Cookson and Eisenack 1960 have two, clearly separated wall layers, not a single wall layer as in Cerbia.
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Sarjeant, 1989, p.94:
Remark:
"Another is their [Stover and Williams, 1987] retention of the genus Cerbia Below, whose type species C. tabulata (Duxbury) was shown by me (1985, pp.93-96) to be a subjective junior synonym of Tenua hystrix Eisenack. Their statement that my illustration shows the processes to be `distributed essentially uniformly over the entire cyst is patently untrue; a comparison of my figure (ibid., pl.X, fig.1) with those of Duxbury (1983, pl.1, figs.6,9,12, text-figs.11,12) and Below (1981, pl.4, fig.5a,b) shows clearly that the processes are, in each instance, exclusively penitabular in situation."
Cerbia, Below, 1981a, p.8.
Taxonomic senior synonym: Tenua Eisenack, according to Sarjeant (1985a, p.93–94; 1992b, p.678) -- however, Duxbury (2002, p.76,78) retained Cerbia.
Type: Davey and Verdier, 1974, pl.92, figs.1,4, as Cyclonephelium tabulatum.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original Description: [Below, 1981]: (Translation: Fensome 1991, p. 123)
Diagnosis:
Proximate to proximochorate, lenticular cyst with a single-layered wall. Round-oval or roundish pentagonal in outline. Apex rounded or with a slight bulge. Antapex rounded or with a lobe and two bulges. Membrane smooth or sculptured.
Paratabulation 4`, 6", Xc, 6```, pc, 1````, Xs. Fields delimited by penitabular ornament, intratabular appendages absent.
Archeopyle apical, (A).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p.55:
Synopsis:
Cysts proximate to proximochorate, lenticular, may be lobate antapically; paratabulation of 4`, 6", Xc, 5-6```, 1p, 1```` and Os indicated by the arrangement of short penitabular processes or tubercles on the autocyst; archeopyle apical type (4A), operculum free- parasulcal notch offset.
Descrpition:
Shape: Lenticular; apical margin obtusely angular,
antapical margin with a single left lobe or bulge or with two lobes or bulges of similar size separated by a relatively shallow median concavity.
Wall relationships: Autophragm only.
Wall features: Basically smooth or faintly sculptured, autophragm ornamented with penitabular tubercules or short processes.
Archeopyle: Apical type [4A], operculum free.
Paratabulation: Indicated by archeopyle and penitabular features; formula: 4`, 6", Xc, 5-6```,1 p, 1```` and 0s; first postcingular paraplate not always delineated.
Paracingulum: Expressed by parallel, transverse rows of tubercles or short processes; undivided; amount of ventral offset varies from virtually none to about twice the longitudinal dimension of the paracingulum.
Parasulcus: Indicated by shallow sigmoidal depression extending posteriorly from the offset parasulcal notch.
Size: Intermediate; length about 80 µm to 95 µm.
Affinities:
Cerbia differs from Canninginopsis Cookson and Eisenack 1962b in having the paratabulation expressed by penitabular rather than parasutural features. On Cyclonephelium Deflandre and Cookson 1955 emended Stover and Evitt 1978, the ornamentation is nontabular and more or less confined to the peripheral areas, but not necessarily so. Cysts of Canningia Cookson and Eisenack 1960 have two, clearly separated wall layers, not a single wall layer as in Cerbia.
-----------------------------------
Sarjeant, 1989, p.94:
Remark:
"Another is their [Stover and Williams, 1987] retention of the genus Cerbia Below, whose type species C. tabulata (Duxbury) was shown by me (1985, pp.93-96) to be a subjective junior synonym of Tenua hystrix Eisenack. Their statement that my illustration shows the processes to be `distributed essentially uniformly over the entire cyst is patently untrue; a comparison of my figure (ibid., pl.X, fig.1) with those of Duxbury (1983, pl.1, figs.6,9,12, text-figs.11,12) and Below (1981, pl.4, fig.5a,b) shows clearly that the processes are, in each instance, exclusively penitabular in situation."