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Cordosphaeridium filosum
Cordosphaeridium filosum, Wilson, 1967
Holotype: Wilson, 1967, figs.2b,32
Locus typicus: Erratics near Minna Bluff, McMurdo Sound, Antarctica
Stratum typicum: Paleocene-Oligocene
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Original description: [Wilson, 1967, p. 66]:
Description:
Test bi-layered comprising fibrous outer cyst and smooth oval inner cyst. Outer cyst extended radially to form 20-24 broad, flat, non- tabular fibrous processes (l = 8-26µm). The longest and broadest being at the poles; processes of equatorial region about one half as long as polar processes; polar processes usually pointed, the other flat- tipped; ventral processes much smaller than those on dorsal surface. Laevorotatory transverse girdle clearly defined by whorl of 6-8 processes whose long, narrow bases are aligned parallel to the equator.
Archaeopyle large, subrounded, precingular, located on dorsal epitheca.
Dimensions:
Holotype l = 102 µm, b = 69 µm, dimensions of inner cyst (61x52) µm.
Range l = 96(107)138 µm, b = 69(81)96 µm (6 specimens)
Affinities:
C. filosum differs considerably from all other described species of Cordosphaeridium in the distribution, size and shape of the processes. Antarctic specimens are very similar to if not identical with the American Eocene forms described as Forma F by Evitt, 1961 who discussed the characteristic features of the species but gave no formal description. The genus Cordosphaeridium Eisenack had not been erected at the time of publication of Evitt's work. C. filosum was recorded as C. cf. inodes in the preliminary species list of McIntyre and Wilson, 1966.
Holotype: Wilson, 1967, figs.2b,32
Locus typicus: Erratics near Minna Bluff, McMurdo Sound, Antarctica
Stratum typicum: Paleocene-Oligocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Wilson, 1967, p. 66]:
Description:
Test bi-layered comprising fibrous outer cyst and smooth oval inner cyst. Outer cyst extended radially to form 20-24 broad, flat, non- tabular fibrous processes (l = 8-26µm). The longest and broadest being at the poles; processes of equatorial region about one half as long as polar processes; polar processes usually pointed, the other flat- tipped; ventral processes much smaller than those on dorsal surface. Laevorotatory transverse girdle clearly defined by whorl of 6-8 processes whose long, narrow bases are aligned parallel to the equator.
Archaeopyle large, subrounded, precingular, located on dorsal epitheca.
Dimensions:
Holotype l = 102 µm, b = 69 µm, dimensions of inner cyst (61x52) µm.
Range l = 96(107)138 µm, b = 69(81)96 µm (6 specimens)
Affinities:
C. filosum differs considerably from all other described species of Cordosphaeridium in the distribution, size and shape of the processes. Antarctic specimens are very similar to if not identical with the American Eocene forms described as Forma F by Evitt, 1961 who discussed the characteristic features of the species but gave no formal description. The genus Cordosphaeridium Eisenack had not been erected at the time of publication of Evitt's work. C. filosum was recorded as C. cf. inodes in the preliminary species list of McIntyre and Wilson, 1966.