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Cerbia formosa
Cerbia formosa, Mao Shaozhi and Norris, 1988
Holotype: Mao Shaozhi and Norris, 1988 , pl.1, fig.9, text-fig.8.2
Locus typicus: Wulagen Formation, Qimugen section, China
Stratum typicum: Late Eocene-Early Oligocene
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Original description: [Mao Shaozhi and Norris, 1988, p. 31-32]:
Diagnosis:
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; possible formula of 4", 6", Xc, 6""", 1p, 1"""".
Description:
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:
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 addition, the processes of C. formosa are less clearly tabular than those of C. tabulata.
Holotype: Mao Shaozhi and Norris, 1988 , pl.1, fig.9, text-fig.8.2
Locus typicus: Wulagen Formation, Qimugen section, China
Stratum typicum: Late Eocene-Early Oligocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Mao Shaozhi and Norris, 1988, p. 31-32]:
Diagnosis:
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; possible formula of 4", 6", Xc, 6""", 1p, 1"""".
Description:
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:
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 addition, the processes of C. formosa are less clearly tabular than those of C. tabulata.