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Hystrichosphaeropsis arctica
Hystrichosphaeropsis arctica Matsuoka and Bujak, 1988
Holotype: Matsuoka and Bujak, 1988, pl.5, figs.1a-b
Paratype: Matsuoka and Bujak, 1988
Locus typicus: Norton Sound COST No. 1 Well, Norton Sound, Bering Sea
Stratum typicum: Hystrichosphaeropsis variabile Zone, Late Miocene
Original diagnosis: Matsuoka and Bujak, 1988, p.47-48
Bicavate intermediate cyst, ellipsoidal to ovoidal, consisting of a thin, smooth transparent periphragm and endophragm adpressed around the paracingulum. Epicyst subspherical with a well-developed pericoel and without an antapical horn. Apical pericoel sometimes reduced: antapical pericoel variable and with coarsely reticulate distal extremity. Parasutural septa strongly reduced and periphragm highly folded, so that the paratabulation is not represented except for the paracingulum and archeopyle sutures. Parasulcus and paracingulum weakly delimited by a shallow indentation of the cyst wall. Archeopyle precingular, formed by the loss of paraplate 3".
Original description: Matsuoka and Bujak, 1988, p.48
The ellipsoidal to ovoidal cyst sometimes possesses a small apical boss which may be rarely absent. The endocyst is also ellipsoidal. The cyst wall comprises a smooth, thin and unornamented periphra gm, and an endophragm adpressed to the periphragm along the paracingulum. The parasutural septa are faintly developed except for a well-developed paracingulum and parasulcus. An antapical pericoel is sometimes present.
Dimension: Holotype; over all length 51Ám, width 33Ám, length of endocyst 41Ám, length of apical horn 4Ám. Range: over all length 51-62Ám, width 33-38Ám, length of endocyst 40-41Ám, length of apical horn 0-4Ám, Number of specimens measured: 6.
Thecal affinities: Unknown, although H. arctica is probably a member of the Gonyaulacaceae based on its precingular archeopyle.
Affinities:
Matsuoka and Bujak, 1988, p.48: Hystrichosphaeropsis arctica is similar to H. obscura Habib and H. variabile, but differs from the former in possessing a smooth thin endophragm and in lacking a well-developed apical pericoel. H. arctica is distinguished from H. variabile in lacking a conspicuous apical horn and sometimes an antapical pericoel, although intermediate forms between H. arctica and H. variabile occur with a variably developed apical horn and parasutural septa. This intergradation suggests that H. arctica and H. variablie may be related.
Holotype: Matsuoka and Bujak, 1988, pl.5, figs.1a-b
Paratype: Matsuoka and Bujak, 1988
Locus typicus: Norton Sound COST No. 1 Well, Norton Sound, Bering Sea
Stratum typicum: Hystrichosphaeropsis variabile Zone, Late Miocene
Original diagnosis: Matsuoka and Bujak, 1988, p.47-48
Bicavate intermediate cyst, ellipsoidal to ovoidal, consisting of a thin, smooth transparent periphragm and endophragm adpressed around the paracingulum. Epicyst subspherical with a well-developed pericoel and without an antapical horn. Apical pericoel sometimes reduced: antapical pericoel variable and with coarsely reticulate distal extremity. Parasutural septa strongly reduced and periphragm highly folded, so that the paratabulation is not represented except for the paracingulum and archeopyle sutures. Parasulcus and paracingulum weakly delimited by a shallow indentation of the cyst wall. Archeopyle precingular, formed by the loss of paraplate 3".
Original description: Matsuoka and Bujak, 1988, p.48
The ellipsoidal to ovoidal cyst sometimes possesses a small apical boss which may be rarely absent. The endocyst is also ellipsoidal. The cyst wall comprises a smooth, thin and unornamented periphra gm, and an endophragm adpressed to the periphragm along the paracingulum. The parasutural septa are faintly developed except for a well-developed paracingulum and parasulcus. An antapical pericoel is sometimes present.
Dimension: Holotype; over all length 51Ám, width 33Ám, length of endocyst 41Ám, length of apical horn 4Ám. Range: over all length 51-62Ám, width 33-38Ám, length of endocyst 40-41Ám, length of apical horn 0-4Ám, Number of specimens measured: 6.
Thecal affinities: Unknown, although H. arctica is probably a member of the Gonyaulacaceae based on its precingular archeopyle.
Affinities:
Matsuoka and Bujak, 1988, p.48: Hystrichosphaeropsis arctica is similar to H. obscura Habib and H. variabile, but differs from the former in possessing a smooth thin endophragm and in lacking a well-developed apical pericoel. H. arctica is distinguished from H. variabile in lacking a conspicuous apical horn and sometimes an antapical pericoel, although intermediate forms between H. arctica and H. variabile occur with a variably developed apical horn and parasutural septa. This intergradation suggests that H. arctica and H. variablie may be related.