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Gonyaulacysta teicha
Gonyaulacysta teicha Davey 1974; emend. Harding, 1990; Emendation: Harding, 1990b, p.34.
Holotype: Davey, 1974, pl.4, figs.5-7; Jan du Chêne et al., 1986, pl.39, fig.4
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Early Barremian
Original diagnosis: Davey, 1974, p. 53
The cyst consists of a subsphaerical, relatively thick walled inner body surrounded by a thin, smooth outer wall. The latter is typically inflated in the apical region and encloses a pericoel; a short, truncated apical horn is present. The tabulation consists of high, thin crests which give rise distally to charcterisically shaped baculate spines. They are of variable shape; they are typically broad, with a proximal neck, and rounded or truncated distally. Medially linkage may be present. The cingulum is stongly helicoidal; the sulcus markedly sigmoidal and widens antapically. The reflected tabulation is 4", 1a, 6"", 6c, 6""", 1p, 1"""". The archaeopyle is formed by the loss of precingular plate 3"" which is usually completely detached.
Dimensions: Range: Overall length 57(69)84 Ám; overall width 50(53)55 Ám; maximum heigth of crests 5-9 Ám; heigth of baculae 2-3 Ám.
Original description: Davey, 1974, p.54
In general the plates of the precingular and apical series are relatively elongate so as to accomodate the apical pericoel. In only one specimen was the apical inflation seen to be very reduced and the pericoel practically absent. The first postcingular plare (1""") is reduced to a thin band bordering the sulcus. The crestal spines are rather variable in shape but are never pointed.
Emended diagnosis: Harding, 1990, p. 34
Shape: Ambitus elongate pentagonal. Greatest width across posterior cingular parasuture. Epicyst about 1.3 times the length of the hypocyst. Short broad apical horn is developed. Slight dorso-ventral compression.
Phragma: Periphragm ambitus elongate pentagonal, up to 0.5 Ám thick, laevigate. Rare intratabular tubercles. Apical paraplates characteristically bear rugulate ridges. Parasutural septa bear cordate/phylloidal denticles although these do vary greatly and may degenerate into distally serrate fenestrate septa. Endophragm is subspherical to ellipsoidal, ca. 1.5 Ám thick with an "orange-peel" type of sculpture. Cyst is delphicavate (pericoel developed beneath the apical horn and the anterior parts of the precingular paraplates), with local suturocavation.
Paratabulation: Sexiform gonyaulacoid (S-type), formula: 2pr, 4", 1a, 6"", 6c, 6""", 1"""", 1p, 5s. Paraplate lu contacts Q ventrally but not dorsally. Porichnion on paraplate A just posterior to A/Q/lu triple junction.
Archaeopyle: Type -/P4, apparently periphragmal paraplate 4 not formed during encystment.
Paracingulum: Prominent, strongly laevorotatory, overhanging, displaced by ca. 3 cingulum widths, strongly indented.
Parasulcus: S-type, sulcal parasutures reduced but not suppressed entirely.
Dimensions: Length (70) 58.2 (46) Ám. Width (56) 44.0 (35) Ám. Specimens = 41 (28).
Affinities:
Davey, 1974, p. 54: G. teicha is considered to be a member of the G. helicoidea/cassidata lineage and is distinguished by the its distinctive club-like crestal spines. G. teicha is most similar to G. cassidata which, however, possesses pointed parasutural spines and usually intratabular trabercles. Reduction of the pericoel, although rarely seen, makes the relationship with G. helicoidea more obvious.
Holotype: Davey, 1974, pl.4, figs.5-7; Jan du Chêne et al., 1986, pl.39, fig.4
Locus typicus: Speeton Clay, Speeton, England
Stratum typicum: Early Barremian
Original diagnosis: Davey, 1974, p. 53
The cyst consists of a subsphaerical, relatively thick walled inner body surrounded by a thin, smooth outer wall. The latter is typically inflated in the apical region and encloses a pericoel; a short, truncated apical horn is present. The tabulation consists of high, thin crests which give rise distally to charcterisically shaped baculate spines. They are of variable shape; they are typically broad, with a proximal neck, and rounded or truncated distally. Medially linkage may be present. The cingulum is stongly helicoidal; the sulcus markedly sigmoidal and widens antapically. The reflected tabulation is 4", 1a, 6"", 6c, 6""", 1p, 1"""". The archaeopyle is formed by the loss of precingular plate 3"" which is usually completely detached.
Dimensions: Range: Overall length 57(69)84 Ám; overall width 50(53)55 Ám; maximum heigth of crests 5-9 Ám; heigth of baculae 2-3 Ám.
Original description: Davey, 1974, p.54
In general the plates of the precingular and apical series are relatively elongate so as to accomodate the apical pericoel. In only one specimen was the apical inflation seen to be very reduced and the pericoel practically absent. The first postcingular plare (1""") is reduced to a thin band bordering the sulcus. The crestal spines are rather variable in shape but are never pointed.
Emended diagnosis: Harding, 1990, p. 34
Shape: Ambitus elongate pentagonal. Greatest width across posterior cingular parasuture. Epicyst about 1.3 times the length of the hypocyst. Short broad apical horn is developed. Slight dorso-ventral compression.
Phragma: Periphragm ambitus elongate pentagonal, up to 0.5 Ám thick, laevigate. Rare intratabular tubercles. Apical paraplates characteristically bear rugulate ridges. Parasutural septa bear cordate/phylloidal denticles although these do vary greatly and may degenerate into distally serrate fenestrate septa. Endophragm is subspherical to ellipsoidal, ca. 1.5 Ám thick with an "orange-peel" type of sculpture. Cyst is delphicavate (pericoel developed beneath the apical horn and the anterior parts of the precingular paraplates), with local suturocavation.
Paratabulation: Sexiform gonyaulacoid (S-type), formula: 2pr, 4", 1a, 6"", 6c, 6""", 1"""", 1p, 5s. Paraplate lu contacts Q ventrally but not dorsally. Porichnion on paraplate A just posterior to A/Q/lu triple junction.
Archaeopyle: Type -/P4, apparently periphragmal paraplate 4 not formed during encystment.
Paracingulum: Prominent, strongly laevorotatory, overhanging, displaced by ca. 3 cingulum widths, strongly indented.
Parasulcus: S-type, sulcal parasutures reduced but not suppressed entirely.
Dimensions: Length (70) 58.2 (46) Ám. Width (56) 44.0 (35) Ám. Specimens = 41 (28).
Affinities:
Davey, 1974, p. 54: G. teicha is considered to be a member of the G. helicoidea/cassidata lineage and is distinguished by the its distinctive club-like crestal spines. G. teicha is most similar to G. cassidata which, however, possesses pointed parasutural spines and usually intratabular trabercles. Reduction of the pericoel, although rarely seen, makes the relationship with G. helicoidea more obvious.