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Gonyaulacysta fastigiata
Gonyaulacysta "fastigiata" Duxbury, 1977, p.36-37, pl.1, figs.8-9,12; text-fig.11. Emendation: Helenes and Lucas-Clark, 1997, p.184, as Stanfordella fastigiata.
NOW Stanfordella. Originally Gonyaulacysta, subsequently (and now) Stanfordella. Questionable assignment: Sarjeant (1982b, p.28) - however, Jan du Chêne et al. (1986a, p.131) included the species in Gonyaulacysta without question.
Holotype: Duxbury, 1977, pl.1, figs.8,12, text-fig.11 and Jan du Chene et al., 1986, pl.43, figs.1-6
Paratype: Duxbury, 1977, pl.1, figs.9
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Hauterivian-Barremian
Original description: Duxbury, 1977, p. 36
Body outline distinctly pentagonal in optical section. Endophragm smooth to finely granular, rounded polygonal without indication of any apical prominence. Periphragm finely granular, developed into fairly high crests which are characteristically distally denticulate. The individual denticles vary from short,
regularly tapering elements to well-developed ones (particularly bordering the antapical plate) which flare slightly for two-thirds of their length and then taper sharply. Tabulation ?4", 6", ?6""", 1p, 1pv, 1"""". Periphragm produced into a prominent apical horn. Archeopyle formed by loss of plate 3".
Dimensions: Holotype 70x68 µm; overall 81(71)58x78(64)54 µm.
Remarks:
Harding, 1990, p. 32: This species is common in the oldest samples studied, becoming less frequent through the early Barremian and dying out by late Barremian time. In contrast to Duxbury"s (1977) specimens, many of those observed in this study show bifurcations of the parasutural septal denticles. The periphragm is interrupted in the parasulcal area, being undeveloped over Im, lu and the flagellar scar region. Paratabulation formula: 2pr, 4", 6", 6c, 6""", 1"""", 1p, 5s. li is very elongated and is only in contact with five paraplates, this results in the loss of the A/li contact as noted by Helenes (1986: 80; text-fig. 4a and d). This is the only modification of the Jurassica paratabulation pattern. A porichnion is developed at the O/A/lu triple junction. No dorsal incidental paraplates have been discerned.
NOW Stanfordella. Originally Gonyaulacysta, subsequently (and now) Stanfordella. Questionable assignment: Sarjeant (1982b, p.28) - however, Jan du Chêne et al. (1986a, p.131) included the species in Gonyaulacysta without question.
Holotype: Duxbury, 1977, pl.1, figs.8,12, text-fig.11 and Jan du Chene et al., 1986, pl.43, figs.1-6
Paratype: Duxbury, 1977, pl.1, figs.9
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Hauterivian-Barremian
Original description: Duxbury, 1977, p. 36
Body outline distinctly pentagonal in optical section. Endophragm smooth to finely granular, rounded polygonal without indication of any apical prominence. Periphragm finely granular, developed into fairly high crests which are characteristically distally denticulate. The individual denticles vary from short,
regularly tapering elements to well-developed ones (particularly bordering the antapical plate) which flare slightly for two-thirds of their length and then taper sharply. Tabulation ?4", 6", ?6""", 1p, 1pv, 1"""". Periphragm produced into a prominent apical horn. Archeopyle formed by loss of plate 3".
Dimensions: Holotype 70x68 µm; overall 81(71)58x78(64)54 µm.
Remarks:
Harding, 1990, p. 32: This species is common in the oldest samples studied, becoming less frequent through the early Barremian and dying out by late Barremian time. In contrast to Duxbury"s (1977) specimens, many of those observed in this study show bifurcations of the parasutural septal denticles. The periphragm is interrupted in the parasulcal area, being undeveloped over Im, lu and the flagellar scar region. Paratabulation formula: 2pr, 4", 6", 6c, 6""", 1"""", 1p, 5s. li is very elongated and is only in contact with five paraplates, this results in the loss of the A/li contact as noted by Helenes (1986: 80; text-fig. 4a and d). This is the only modification of the Jurassica paratabulation pattern. A porichnion is developed at the O/A/lu triple junction. No dorsal incidental paraplates have been discerned.