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Tetranguladinium minqiaoense
Tetranguladinium minqiaoense Qian Ze-shu et al. 1986 ex Fensome et al., 1990
The name, Tetranguladinium minqiaoense was not validly published in Qian Zeshu et al., 1986 since the generic name Tetranguladinium was not validly published until 1988.
Holotype:Qian Ze-shu et al. 1986, pl.1, fig.39
Age: Paleocene-Eocene
Description: Qian Ze-shu et al. 1986
Tests have "H"-shaped outline. Body has square outline. At each of four angles is a long flatly tubular process formed by the periphragm. Two sides of processes parallel; ends truncated, open. Surface of periphragm fairly rough, with linear creases. Endophragm forms inner body, subcircular. Wall thin; surface nearly smooth. Except at base of processes, inner body and periphragm closely appressed. No cingulum or archaeopyle.
Size: In holotype specimen, test (diagonally) 74 x 70 µm; inner body 28 x 30 µm; long processes 20 x 9 µm and short processes 10 x 6 µm.
Supplemental description: Batten and Lister, 1988, p.359
Cavate cyst. Thin-walled (1 µm or less), unornamented pericyst without paratabulation, extended into four horns of unequal length one of which is rather longer than the other three. Pericyst is basically "H"-shaped in outline but extended in direction of longest horn which gives it a cruciform appearance. Periphragm extensively wrinkled along and between horns which are hollow, of equal width throughout their length and somewhat flattened; distal terminations are truncated and also constricted so that it has not been possible to determine whether they are open or closed. Endocyst is difficult to observe since it is in close contact with pericyst, separated by only a slight lateral pericoel. It appears to be rhomboidal but bulges a little towards long horn of pericyst and on either side of it, and extends slightly into the shorter, diagonally opposite horns.
Length along longest axis is c. 95 µm; length and width of endocyst is c. 45 µm.
Affinities:
Qian Ze-shu et al. 1986: This species differs from Tetranguladinium conspicuum in its smaller individuals, closely appressed inner body and periphragm, and fine, short processes with evenly truncated ends.
Batten and Lister, 1988, p.359: This rare form differs from T. conspicuum in having much less voluminous horns and a barely discernible endocyst in close contact with the pericyst. We are not convinced, however, that the species is clearly distinct; it may be necessary in due course to place it in synonymy.
The name, Tetranguladinium minqiaoense was not validly published in Qian Zeshu et al., 1986 since the generic name Tetranguladinium was not validly published until 1988.
Holotype:Qian Ze-shu et al. 1986, pl.1, fig.39
Age: Paleocene-Eocene
Description: Qian Ze-shu et al. 1986
Tests have "H"-shaped outline. Body has square outline. At each of four angles is a long flatly tubular process formed by the periphragm. Two sides of processes parallel; ends truncated, open. Surface of periphragm fairly rough, with linear creases. Endophragm forms inner body, subcircular. Wall thin; surface nearly smooth. Except at base of processes, inner body and periphragm closely appressed. No cingulum or archaeopyle.
Size: In holotype specimen, test (diagonally) 74 x 70 µm; inner body 28 x 30 µm; long processes 20 x 9 µm and short processes 10 x 6 µm.
Supplemental description: Batten and Lister, 1988, p.359
Cavate cyst. Thin-walled (1 µm or less), unornamented pericyst without paratabulation, extended into four horns of unequal length one of which is rather longer than the other three. Pericyst is basically "H"-shaped in outline but extended in direction of longest horn which gives it a cruciform appearance. Periphragm extensively wrinkled along and between horns which are hollow, of equal width throughout their length and somewhat flattened; distal terminations are truncated and also constricted so that it has not been possible to determine whether they are open or closed. Endocyst is difficult to observe since it is in close contact with pericyst, separated by only a slight lateral pericoel. It appears to be rhomboidal but bulges a little towards long horn of pericyst and on either side of it, and extends slightly into the shorter, diagonally opposite horns.
Length along longest axis is c. 95 µm; length and width of endocyst is c. 45 µm.
Affinities:
Qian Ze-shu et al. 1986: This species differs from Tetranguladinium conspicuum in its smaller individuals, closely appressed inner body and periphragm, and fine, short processes with evenly truncated ends.
Batten and Lister, 1988, p.359: This rare form differs from T. conspicuum in having much less voluminous horns and a barely discernible endocyst in close contact with the pericyst. We are not convinced, however, that the species is clearly distinct; it may be necessary in due course to place it in synonymy.