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Gonyaulacysta speciosa
Gonyaulacysta speciosa Harding, 1990b, p.33, pl.14, figs.1-15; pl.15, figs.12-14; text-fig.14 ex Harding in Williams et al., 1998, p.257.
This name was not validly published in Harding (1990b) since the lodgment of the holotype was not specified (I.C.B.N. Article 40.7).
Holotype: Harding, 1990, pl. 14, fig.1
Locus typicus: O. Gott, Lower Saxony, Germany
Stratum typicum: Early Barremian
Original diagnosis: Harding, 1990, p.33
Shape: Slightly elongate pentagonal ambitus. Greatest width across posterior paracingular suture. Epicyst (less apical horn) and hypocyst of approximately equal length. An elongate apical horn is developed. Slight dorso-ventral compression.
Phragma: The periphragm is only partially developed. Two distinct wall layers are present in the parasutural areas but no periphragm is developed over the central parts of the paraplates of the hypocystal or the cingular or precingular series. Thus the periphragm forms a "roof~ over the parasutures of all but the apical series, here it is complete, forming a "tent" over the apex of the endocyst. The periphragm (0.4 llm thick), is laevigate with rare tubercles. Paratabulation is delineated by periphragmal septa which are distally denticulate. The denticles vary in shape from phylloidal to acuminate. The denticles are absent from the reduced septa in the apical and parasulcal regions. The endophragm is ca. 0.6 Ám thick, subspherical with the entire surface covered in clumped, fused granules (which are sometimes developed into solid cylindrical setae). The cyst is delphicavate (involving a pericoel between the apical and the anterior part of the precingular series), with localised suturocavation.
Paratabulation: Sexiform gonyaulacoid (S-type), formula: 2pr, 4", 1a, 6", 6c, 6""", 1"""", 1p, 5s. Two preapicals are present, lu is slender and contacts Q dorsally and ventrally. Porichnion at A/Q./lu triple junction.
Archaeopyle: Type -/P4, apparently paraplate 4 in the periphragm was not formed on encystment, operculum consists of endophragmal plate 4 alone.
Paracingulum: Prominent, strongly laevorotatory, overhanging, displaced by--3 cingulum widths. Strongly indented due to the suturocavate nature of the bounding parasutures. The parasutural septa which delineate the paracingulum bear a single line of rounded tubercles along the plane of the septum.
Parasulcus: S-type, sulcal parasutures reduced. Periphragm developed over all the sucal paraplates save for the intratabular areas of X and Z.
Dimensions: Length (65) 54.2 (46) Ám. Width (45) 41.0 (37) Ám. Specimens = 11 (9).
Affinities:
Harding, 1990, p. 33: This is an easily recognised species due to the striking sculpture of the exposed endophragm. It differs from Gonyaulacysta centriconnata Riding 1983, which is also suturocavate, in its partial development of the periphragm, the strong sculpture, and the S-type (not L-type) ventral organisation. G. teicha Davey 1974 has the inflated apical pericoel of this new species and rare suturocavation, however, it also has a complete periphragm and an unsculptured endophragm.
Paratabulation pattern following Helenes (1986) is of the Spinifera type, there being a contact between paraplates A and ai.
This species has proved to be have a very restricted time range, being a good marker for the Hauterivian/Barremian boundary.
This name was not validly published in Harding (1990b) since the lodgment of the holotype was not specified (I.C.B.N. Article 40.7).
Holotype: Harding, 1990, pl. 14, fig.1
Locus typicus: O. Gott, Lower Saxony, Germany
Stratum typicum: Early Barremian
Original diagnosis: Harding, 1990, p.33
Shape: Slightly elongate pentagonal ambitus. Greatest width across posterior paracingular suture. Epicyst (less apical horn) and hypocyst of approximately equal length. An elongate apical horn is developed. Slight dorso-ventral compression.
Phragma: The periphragm is only partially developed. Two distinct wall layers are present in the parasutural areas but no periphragm is developed over the central parts of the paraplates of the hypocystal or the cingular or precingular series. Thus the periphragm forms a "roof~ over the parasutures of all but the apical series, here it is complete, forming a "tent" over the apex of the endocyst. The periphragm (0.4 llm thick), is laevigate with rare tubercles. Paratabulation is delineated by periphragmal septa which are distally denticulate. The denticles vary in shape from phylloidal to acuminate. The denticles are absent from the reduced septa in the apical and parasulcal regions. The endophragm is ca. 0.6 Ám thick, subspherical with the entire surface covered in clumped, fused granules (which are sometimes developed into solid cylindrical setae). The cyst is delphicavate (involving a pericoel between the apical and the anterior part of the precingular series), with localised suturocavation.
Paratabulation: Sexiform gonyaulacoid (S-type), formula: 2pr, 4", 1a, 6", 6c, 6""", 1"""", 1p, 5s. Two preapicals are present, lu is slender and contacts Q dorsally and ventrally. Porichnion at A/Q./lu triple junction.
Archaeopyle: Type -/P4, apparently paraplate 4 in the periphragm was not formed on encystment, operculum consists of endophragmal plate 4 alone.
Paracingulum: Prominent, strongly laevorotatory, overhanging, displaced by--3 cingulum widths. Strongly indented due to the suturocavate nature of the bounding parasutures. The parasutural septa which delineate the paracingulum bear a single line of rounded tubercles along the plane of the septum.
Parasulcus: S-type, sulcal parasutures reduced. Periphragm developed over all the sucal paraplates save for the intratabular areas of X and Z.
Dimensions: Length (65) 54.2 (46) Ám. Width (45) 41.0 (37) Ám. Specimens = 11 (9).
Affinities:
Harding, 1990, p. 33: This is an easily recognised species due to the striking sculpture of the exposed endophragm. It differs from Gonyaulacysta centriconnata Riding 1983, which is also suturocavate, in its partial development of the periphragm, the strong sculpture, and the S-type (not L-type) ventral organisation. G. teicha Davey 1974 has the inflated apical pericoel of this new species and rare suturocavation, however, it also has a complete periphragm and an unsculptured endophragm.
Paratabulation pattern following Helenes (1986) is of the Spinifera type, there being a contact between paraplates A and ai.
This species has proved to be have a very restricted time range, being a good marker for the Hauterivian/Barremian boundary.