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Hystrichosphaeropsis variabilis
Hystrichosphaeropsis variabile Matsuoka and Bujak, 1988
Holotype: Matsuoka and Bujak, 1988, pl.5, figs.5a-b, text-fig.8
Paratype: Matsuoka and Bujak, 1988
Locus typicus: Norton Sound COST No. 1 well, 3930-3960ft, Norton Sound, Bering Sea
Stratum typicum: Hystrichosphaeropsis variabile Zone; Late Miocene
Original diagnosis: Matsuoka and Bujak, 1988, p.49-50
Ovoidal to ellipsoidal, intermediate cavate cyst. Epicyst broadly conical with a short apical horn; hypocyst subspherical with a conspicuous pericoel and without horns. Cyst wall comprising thin, smooth to chagrinate periphragm and a thin endophragm, both phragma adpressed at the paracingulum and over most of the epicyst. Parasutural septa high and smooth, without distal ornament. No furcate processes occur gonally.
Paratabulation incompletely reflected by parasutural septa as 4" (?), 6", 6c, 6""", 1p (?), 1"""", xs. Paracingulum indicated by six rectangular paraplates which are transversely expanded. Parasulcus delimited by parasutural ridges, but number of parasulcal plates unknown. Archeopyle precingular, sometimes reduced and formed by the loss of paraplate 3".
Original description: Matsuoka and Bujak, 1988, p.50
The overall cyst shape varies from elongate ovoidal to polygonal. A smooth to chagrinate periphragm and endophragm are mostly in contact on the epicyst, the epicystal pericoel being relatively small and cornucavate. An apical horn is usually present and is short and distally closed. The hypocystal pericoel is variably developed and is distally open with a hypocystal flange that is sometimes irregularly reticulate to roughly denticulate. The parasutural crests are smooth, high and membranous, without processes and easily deformed. The paracingulum is well-developed and almost circular, and the parasulcus is represented by a shallow indentation of the periphragm. Owing to the thin and smooth parasutural septa, the parasuture between the 1" and 4" is often reduced. The paratabulation is often incompletely indicated. The archeopyle is trapezoidal and precingular (3" ).
Dimensions: Holotype; overall length 71 Ám, width 40 Ám, length of endocyst 48 Ám, length of apical horn 8 Ám, width of paracingulum ca. 6 Ám. Range: overall length 48-71 Ám, width 35-40 Ám, length of endocyst 35-48 Ám, length of apical horn 5-8 Ám. Number of specimens measured: 6.
Thecal afflnitles: Unknown, but possibly related to the Gonyaulacaceae.
Affinities:
Matsuoka and Bujak, 1988, p.50: Hystrichosphaeropsis variabile is similar to Spiniferites frigidus Harland and Reid, which was first described as Rottnestia amphicavata by Dobell and Norris (in Harland et al., 1980), in possessing a well-developed antapical pericoel, but differs in lacking processes. H. variabile also resembles H. obscura, but differs in having a smooth surface of the inner capsule, and a more strongly developed antapical pericoel with roughly reticulate to denticulate distal extremity.
Holotype: Matsuoka and Bujak, 1988, pl.5, figs.5a-b, text-fig.8
Paratype: Matsuoka and Bujak, 1988
Locus typicus: Norton Sound COST No. 1 well, 3930-3960ft, Norton Sound, Bering Sea
Stratum typicum: Hystrichosphaeropsis variabile Zone; Late Miocene
Original diagnosis: Matsuoka and Bujak, 1988, p.49-50
Ovoidal to ellipsoidal, intermediate cavate cyst. Epicyst broadly conical with a short apical horn; hypocyst subspherical with a conspicuous pericoel and without horns. Cyst wall comprising thin, smooth to chagrinate periphragm and a thin endophragm, both phragma adpressed at the paracingulum and over most of the epicyst. Parasutural septa high and smooth, without distal ornament. No furcate processes occur gonally.
Paratabulation incompletely reflected by parasutural septa as 4" (?), 6", 6c, 6""", 1p (?), 1"""", xs. Paracingulum indicated by six rectangular paraplates which are transversely expanded. Parasulcus delimited by parasutural ridges, but number of parasulcal plates unknown. Archeopyle precingular, sometimes reduced and formed by the loss of paraplate 3".
Original description: Matsuoka and Bujak, 1988, p.50
The overall cyst shape varies from elongate ovoidal to polygonal. A smooth to chagrinate periphragm and endophragm are mostly in contact on the epicyst, the epicystal pericoel being relatively small and cornucavate. An apical horn is usually present and is short and distally closed. The hypocystal pericoel is variably developed and is distally open with a hypocystal flange that is sometimes irregularly reticulate to roughly denticulate. The parasutural crests are smooth, high and membranous, without processes and easily deformed. The paracingulum is well-developed and almost circular, and the parasulcus is represented by a shallow indentation of the periphragm. Owing to the thin and smooth parasutural septa, the parasuture between the 1" and 4" is often reduced. The paratabulation is often incompletely indicated. The archeopyle is trapezoidal and precingular (3" ).
Dimensions: Holotype; overall length 71 Ám, width 40 Ám, length of endocyst 48 Ám, length of apical horn 8 Ám, width of paracingulum ca. 6 Ám. Range: overall length 48-71 Ám, width 35-40 Ám, length of endocyst 35-48 Ám, length of apical horn 5-8 Ám. Number of specimens measured: 6.
Thecal afflnitles: Unknown, but possibly related to the Gonyaulacaceae.
Affinities:
Matsuoka and Bujak, 1988, p.50: Hystrichosphaeropsis variabile is similar to Spiniferites frigidus Harland and Reid, which was first described as Rottnestia amphicavata by Dobell and Norris (in Harland et al., 1980), in possessing a well-developed antapical pericoel, but differs in lacking processes. H. variabile also resembles H. obscura, but differs in having a smooth surface of the inner capsule, and a more strongly developed antapical pericoel with roughly reticulate to denticulate distal extremity.