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Tenua formosa
From Fensome et al., 2019:
Tenua formosa (Mao Shaozhi and Norris, 1988, p.31–32, pl.1, figs.9–10; text-fig.8, nos.1–2) Lentin and Williams, 1993, p.639.
Holotype: Mao Shaozhi and Norris, 1988, pl.1, fig.9; text-fig.8, no.2; Fensome et al., 2019a, fig.14M.
NOW Cerbia? Originally Cerbia, subsequently Tenua Eisenack, thirdly (and now) Cerbia?.
Fensome et al. (2019a, p.35) questionably retained this species in Cerbia.
Taxonomic junior synonym: Cerbia (al. Tenua) suturispinosa, according to Fensome et al. (2019a, p.35).
Paratype: Mao Shaozhi and Norris, 1988
Locus typicus: Wulagen Formation, Qimugen section, China
Stratum typicum: Late Eocene-early Oligocene
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Original diagnosis: Mao Shaozhi and Norris, 1988, p. 31: Cerbia formosa
Cyst proximate to proximochorate, dorsoventrally compressed, with an apical prominence. Antapical end either rounded or slightly concave. Processes penitabular, slender, and sinuous, partly connected proximally forming arcuate and soleate complexes; mostly acuminate, capitate, and bifurcate, seldom trifurcate distally. Archeopyle apical, type (4A); operculum typically detached but in situ. Archeopyle suture zigzag, with accessory sutures indicating six precingular plates. Cingulum slightly levorotatory, indicated by alignment of processes. Sulcus broader towards antapex; sulcal notch offset to left on ventral surface. Tabulation indicated by penitabular processes, gonyaulacacean; posssible formula of 4", 6", Xc, 6""", 1p, 1"""".
Original description: Mao Shaozhi and Norris, 1988, p. 31-32: Cerbia formosa
Ambitus rounded pentagonal to rounded biconical, prolonged into an obtuse and short tapering apical horn. Hypotract either semicircular or, more commonly, with two poorly developed, unequal antapical lobes; left one slightly longer than right one. Processes relatively long (usually 6 to 8 µm, sometimes up to 10 to 12 µm), narrow (usually 0.5 to 1 µm), sinuous, delicate; usually secondarily flattened in random orientation. Plate boundaries usually obscured. Cingulum delineated by processes about 8 to 10 µm in breadth. Dimensions: Length (including operculum) 65 to 68 µm (holotype 65 µm), width 41 to 68 µm (holotype 63 µm).
Affinites:
Mao Shaozhi and Norris, 1988, p. 32: Cerbia formosa
Cerbia formosa is closely comparable to C. tabulata (Davey and Verdier, 1974), but the latter differs in having short, stout, capitate processes, which are rarely branched distally; in C. formosa the processes are long, slender, curved, and frequently branched. In adddition, the processes of C. formosa are less clearly tabular than those of C. tabulata.
Tenua formosa (Mao Shaozhi and Norris, 1988, p.31–32, pl.1, figs.9–10; text-fig.8, nos.1–2) Lentin and Williams, 1993, p.639.
Holotype: Mao Shaozhi and Norris, 1988, pl.1, fig.9; text-fig.8, no.2; Fensome et al., 2019a, fig.14M.
NOW Cerbia? Originally Cerbia, subsequently Tenua Eisenack, thirdly (and now) Cerbia?.
Fensome et al. (2019a, p.35) questionably retained this species in Cerbia.
Taxonomic junior synonym: Cerbia (al. Tenua) suturispinosa, according to Fensome et al. (2019a, p.35).
Paratype: Mao Shaozhi and Norris, 1988
Locus typicus: Wulagen Formation, Qimugen section, China
Stratum typicum: Late Eocene-early Oligocene
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Original diagnosis: Mao Shaozhi and Norris, 1988, p. 31: Cerbia formosa
Cyst proximate to proximochorate, dorsoventrally compressed, with an apical prominence. Antapical end either rounded or slightly concave. Processes penitabular, slender, and sinuous, partly connected proximally forming arcuate and soleate complexes; mostly acuminate, capitate, and bifurcate, seldom trifurcate distally. Archeopyle apical, type (4A); operculum typically detached but in situ. Archeopyle suture zigzag, with accessory sutures indicating six precingular plates. Cingulum slightly levorotatory, indicated by alignment of processes. Sulcus broader towards antapex; sulcal notch offset to left on ventral surface. Tabulation indicated by penitabular processes, gonyaulacacean; posssible formula of 4", 6", Xc, 6""", 1p, 1"""".
Original description: Mao Shaozhi and Norris, 1988, p. 31-32: Cerbia formosa
Ambitus rounded pentagonal to rounded biconical, prolonged into an obtuse and short tapering apical horn. Hypotract either semicircular or, more commonly, with two poorly developed, unequal antapical lobes; left one slightly longer than right one. Processes relatively long (usually 6 to 8 µm, sometimes up to 10 to 12 µm), narrow (usually 0.5 to 1 µm), sinuous, delicate; usually secondarily flattened in random orientation. Plate boundaries usually obscured. Cingulum delineated by processes about 8 to 10 µm in breadth. Dimensions: Length (including operculum) 65 to 68 µm (holotype 65 µm), width 41 to 68 µm (holotype 63 µm).
Affinites:
Mao Shaozhi and Norris, 1988, p. 32: Cerbia formosa
Cerbia formosa is closely comparable to C. tabulata (Davey and Verdier, 1974), but the latter differs in having short, stout, capitate processes, which are rarely branched distally; in C. formosa the processes are long, slender, curved, and frequently branched. In adddition, the processes of C. formosa are less clearly tabular than those of C. tabulata.