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Cooksoniella vnigrii
Cooksoniella vnigrii, Vozzhennikova, 1967
Originally Cooksoniella, subsequently Chatangiella.
Tax. jr. synonym of Deflandrea (now Chatangiella) verrucosa Manum, 1973, according to Yun, 1981.
Tax. jr. synonym of Chatangiella granulifera (Manum, 1963) Lentin and Williams, 1976, according to Lentin and Vozzhennikova, 1990. Wheeler and Sarjeant, 1990, retained Chatangiella vnigrii as a separate species.
Since Lentin and Vozzhennikova, 1990, appeared one month later than Wheeler and Sarjeant, 1990, the former authors are followed.
Wheeler and Sarjeant, 1990, suggested that the correct spelling for the species epithet could be vnigriorum.
Holotype: Vozzhennikova, 1967, pl.109, figs.2a-b; Lentin and Vozzhennikova, 1990, pl.5, figs.4-5; textfig.21
Locus typicus: Siberia (Khatanga depression), Russia
Stratum typicum: Turonian-Santonian
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Original description: [Vozzhennikova, 1967, p. 185]: (Translation: Lentin and Vozzhennikova, 1990):
Description:
Theca elongated along the longitudinal axis, with convex equatorial part and some tapering at the level of the upper and lower boundaries of the internal body. Theca divided into two equal parts. Epitheca broad and rounded anteriorly to form a straight "shoulder" to the outline.
Apical horn short, conical, somewhat bent and bluntly rounded at the distal end. Hypotheca with straight or slightly convex walls posteriorly and with its posterior margin truncated or curved as a result of the formation of the two antapical horns of different size. One horn is short, broadly triangular and rounded at the end, the other is longer, triangular and acutely pointed. Transverse furrow equatorial, annulate. Between the ends of the furrow, on the ventral side, there is a depression which extends a little way onto the epitheca and ends at the antapex of the hypotheca. This depression corresponds in position to the longitudinal furrow. The internal body is compressed so that its width exceeds its length and the two sides are closely applied to the lateral walls of the theca. Surface of internal body granulate, thickness of wall uniform or slightly greater towards the poles. Thecal surface punctate, divided into fields by coarse spines. Similar spines occur on the edge of the transverse furrow, where they are interrupted in places which apparently correspond to the position of the sutures. Pylome of rounded hexagonal form.
Dimensions:
Holotype - length of pericyst 92 µm, width 49 µm, width of paracingulum about 6 µm; length of endocyst 42 µm, width 48 µm.
Range, length of pericyst 100 - 103 µm, width 49 - 62 µm, width of paracingulum about 6 µm; length of endocyst 40 - 43 µm, width 49 - 62 µm.
Originally Cooksoniella, subsequently Chatangiella.
Tax. jr. synonym of Deflandrea (now Chatangiella) verrucosa Manum, 1973, according to Yun, 1981.
Tax. jr. synonym of Chatangiella granulifera (Manum, 1963) Lentin and Williams, 1976, according to Lentin and Vozzhennikova, 1990. Wheeler and Sarjeant, 1990, retained Chatangiella vnigrii as a separate species.
Since Lentin and Vozzhennikova, 1990, appeared one month later than Wheeler and Sarjeant, 1990, the former authors are followed.
Wheeler and Sarjeant, 1990, suggested that the correct spelling for the species epithet could be vnigriorum.
Holotype: Vozzhennikova, 1967, pl.109, figs.2a-b; Lentin and Vozzhennikova, 1990, pl.5, figs.4-5; textfig.21
Locus typicus: Siberia (Khatanga depression), Russia
Stratum typicum: Turonian-Santonian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Vozzhennikova, 1967, p. 185]: (Translation: Lentin and Vozzhennikova, 1990):
Description:
Theca elongated along the longitudinal axis, with convex equatorial part and some tapering at the level of the upper and lower boundaries of the internal body. Theca divided into two equal parts. Epitheca broad and rounded anteriorly to form a straight "shoulder" to the outline.
Apical horn short, conical, somewhat bent and bluntly rounded at the distal end. Hypotheca with straight or slightly convex walls posteriorly and with its posterior margin truncated or curved as a result of the formation of the two antapical horns of different size. One horn is short, broadly triangular and rounded at the end, the other is longer, triangular and acutely pointed. Transverse furrow equatorial, annulate. Between the ends of the furrow, on the ventral side, there is a depression which extends a little way onto the epitheca and ends at the antapex of the hypotheca. This depression corresponds in position to the longitudinal furrow. The internal body is compressed so that its width exceeds its length and the two sides are closely applied to the lateral walls of the theca. Surface of internal body granulate, thickness of wall uniform or slightly greater towards the poles. Thecal surface punctate, divided into fields by coarse spines. Similar spines occur on the edge of the transverse furrow, where they are interrupted in places which apparently correspond to the position of the sutures. Pylome of rounded hexagonal form.
Dimensions:
Holotype - length of pericyst 92 µm, width 49 µm, width of paracingulum about 6 µm; length of endocyst 42 µm, width 48 µm.
Range, length of pericyst 100 - 103 µm, width 49 - 62 µm, width of paracingulum about 6 µm; length of endocyst 40 - 43 µm, width 49 - 62 µm.