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Gonyaulacysta kostromiensis
Gonyaulacysta kostromiensis (Vozzhennikova, 1967, p.85, pl.26, figs.1–6; pl.27, figs.1–2) Sarjeant, 1969, p.10. Emendation: Harding, 1996, p.353,355, as Nelchinopsis kostromiensis.
Now Nelchinopsis kostromiensis. Originally Gonyaulax kostromiensis, subsequently Gonyaulacysta kostromiensis, thirdly (and now) Nelchinopsis kostromiensis. Wiggins, 1972, transferred this species to Nelchinopsis Wiggins, 1975. Duxbury, 1977, retained the species in Gonyaulacysta, but Stover and Williams, 1987, agreed with Wiggins, 1972.
Taxonomic junior synonym: Alaskadinium wigginsii, according to Stover and Williams (1987, p.11).
Holotype: Vozzhennikova, 1967, pl.26, figs.1-6; Jan du Chêne et al., 1986, pl.44, figs.7-8; Lentin and Vozzhennikova, 1990, text-fig.64 (lost according to Lentin and Vozzhennikova, 1990)
Lectotype: Lentin and Vozzhennikova, 1990, pl.15, figs.5-6 (designated by Lentin and Vozzhennikova, 1990)
Locus typicus: Kostromsk region, Russia
Stratum typicum: Necomian, probably Valanginian or Early Hauterivian
Translation Vozzhennikova, 1967: Lees, 1971
Original description: Vozzhennikova, 1967, p. 85-85: Gonyaulax kostromiensis
Theka with a rounded polygonal outline. Epitheca larger than hypotheca and with broadly rounded, coloured, subconical apical horn. The theca may have short processes wich appearently represent the raised up margins to the apical plates. Transverse furrow twisted to the left, its ends seperaed from each other by a distance equivalent to 1 - 1 1/2 times the width of the furrow. The longitudinal furrow either extends to the antapex or is seperated from the antapex by the small accessory plate (npb) which is difficult to distinguish becauce of its ornamentation. Plate formula: on the epitheka 4a + 6np, on the hypotheca 6zd + 1cp, + ?npb + 1a". The first apical plate does not quite reach the left end of the transverse furrow. The anterior equatorial plates are trapeziform, the sixth being slightly larger smaller than the others. The first posterior equatorial plate is distinguished by its smaller size. Below it lies the small accessory plate. The antapical plate is large and polygonal. The surface of the thecal envelope is densely covered with spines. The margins of the transverse furrow and the plates are fringhed with tall, hyaline, toothed processes. Large spines occur at the angles where the plates join. No pylome has been observed.
Dimensions: holotype length 61.8 Ám, breadth 50.6 Ám, width of transverse furrow about 6 Ám, length of apical horn 14 Ám. In other specimens length 50.6-64.6 Ám, breadth 50.6-56.2 Ám, width of transverse furrow 6 Ám, length of apical horn 8-14 Ám, width of toothed processes 6-8 Ám.
Now Nelchinopsis kostromiensis. Originally Gonyaulax kostromiensis, subsequently Gonyaulacysta kostromiensis, thirdly (and now) Nelchinopsis kostromiensis. Wiggins, 1972, transferred this species to Nelchinopsis Wiggins, 1975. Duxbury, 1977, retained the species in Gonyaulacysta, but Stover and Williams, 1987, agreed with Wiggins, 1972.
Taxonomic junior synonym: Alaskadinium wigginsii, according to Stover and Williams (1987, p.11).
Holotype: Vozzhennikova, 1967, pl.26, figs.1-6; Jan du Chêne et al., 1986, pl.44, figs.7-8; Lentin and Vozzhennikova, 1990, text-fig.64 (lost according to Lentin and Vozzhennikova, 1990)
Lectotype: Lentin and Vozzhennikova, 1990, pl.15, figs.5-6 (designated by Lentin and Vozzhennikova, 1990)
Locus typicus: Kostromsk region, Russia
Stratum typicum: Necomian, probably Valanginian or Early Hauterivian
Translation Vozzhennikova, 1967: Lees, 1971
Original description: Vozzhennikova, 1967, p. 85-85: Gonyaulax kostromiensis
Theka with a rounded polygonal outline. Epitheca larger than hypotheca and with broadly rounded, coloured, subconical apical horn. The theca may have short processes wich appearently represent the raised up margins to the apical plates. Transverse furrow twisted to the left, its ends seperaed from each other by a distance equivalent to 1 - 1 1/2 times the width of the furrow. The longitudinal furrow either extends to the antapex or is seperated from the antapex by the small accessory plate (npb) which is difficult to distinguish becauce of its ornamentation. Plate formula: on the epitheka 4a + 6np, on the hypotheca 6zd + 1cp, + ?npb + 1a". The first apical plate does not quite reach the left end of the transverse furrow. The anterior equatorial plates are trapeziform, the sixth being slightly larger smaller than the others. The first posterior equatorial plate is distinguished by its smaller size. Below it lies the small accessory plate. The antapical plate is large and polygonal. The surface of the thecal envelope is densely covered with spines. The margins of the transverse furrow and the plates are fringhed with tall, hyaline, toothed processes. Large spines occur at the angles where the plates join. No pylome has been observed.
Dimensions: holotype length 61.8 Ám, breadth 50.6 Ám, width of transverse furrow about 6 Ám, length of apical horn 14 Ám. In other specimens length 50.6-64.6 Ám, breadth 50.6-56.2 Ám, width of transverse furrow 6 Ám, length of apical horn 8-14 Ám, width of toothed processes 6-8 Ám.