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Tubotuberella rhombiformis
From Fensome et al., 2019:
Tubotuberella rhombiformis Vozzhennikova, 1967, p.180, pl.101, figs.1a–b,2a–b; pl.102, figs.1,2a–b,3a–b; pl.104, figs.1–3.
Emendation: Brideaux, 1977, p.36. Holotype: Vozzhennikova, 1967, pl.101, figs.2a–b; pl.104, fig.2, lost according to Lentin and Vozzhennikova (1990, p.117–118).
Lectotype: Lentin and Vozzhennikova, 1990, pl.14, figs.1–2; text-fig.68, designated by Lentin and Vozzhennikova (1990, p.117). Contrary to the statements of Stover and Evitt (1978, p.197), Vozzhennikova (1967, p.180) cited only one specimen for the holotype. Lentin and Vozzhennikova (1990, p.117) provided an "expanded description" for this species.
Stratum typicum: Late Jurassic
Locus typicus: Well borings near Kuntsevo, well 15, Chulkovo, Moscow region, Russia
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Translation Vozzhennikova, 1967: Lees in Sarjeant, 1971 (Ed.)
Original diagnosis: Vozzhennikova, 1967, p. 179-180
Theca rhomboid, somewhat drawn out ventrally. The lateral walls of the theca are convex and surround the large ovoid or elliptical internal body. Epitheca conical with a small apical process. Hypotheca gradually tapers towards the antapex and ends in a square opening. From the transverse furrow to the poles run smooth ribs which from trapeziform fields on the epitheca and on the antapical part of the hypotheca contribute towards the formation of a tetrahedral tapering tube. Transverse furrow shallow, annulate, its ends widely separated. The ribs running from the ends to the poles delimit a broad ventral field. The envelope of the internal body is thin, smooth and pale yellow in colour. Pylome rounded trapeziform with its lower edge almost touching the transverse furrow and the upper edge not far from the apical end of the theca.
Dimensions:
holotype - length 121.5 µm, breadth 64.8 µm, length of internal body 62.4 µm, breadth 59.5 µm, width of transverse furrow 8.1 µm.
In other specimens - length 83.7-94.5 µm, breadth 40.5-51.3 µm, length of internal body 43.2-54.0 µm, breadth 37.8-48.6 µm, width of transverse furrow 5.5-8.0 µm.
Emended description: Brideaux 1977, p. 36
As for the genus (emend. Brideaux 1977) with these particular features: the parasutaral ridges smooth and unornamented; the epipericoel conical in outline.
Expanded description: Lentin and Vozzhennikova, 1967, p.117
Cysts proximate, elongate ellipsoidal with one short apical horn and one long tetrahedral, tubular antapical projection; endocyst distinctly oval, with or without short apical horn; bicavate, hypocyst drawn out into a long posterior extension which is four-sited and open distally where the 1"""" paraplate appears to be absent. Paraphragm and endophragm smooth to minutely granulose; parasutural ridges are low and discontinuously outline paratabulation. Paratabulation gonyaulacacean, outlined by low ridges, formula: 3-4", 6"",?c, 5""", 1"""". The archeopyle is precingular (Type P, 3"" only), attached along the paracingular margin. Paracingulum indistinctly indicated by low ridges. Parasulcus not indicated or indicated only as a flat area on ventral hypocyst.
Size: Holotype, length 121 µm, width 65 µm; endocyst length 62 µm, width 59 µm; Lectotype length 123 µm. Range, length 83-125 µm, width 40-67 µm.
Affinities:
Lentin and Vozzhennikova, 1990, p.117: Tubotuberella rhombiformis most closely resembles T. apatela (Cookson and Eisenack) Ioannides et al., which does not have a paracingulum and has less well developed apical and antapical pericoels.
Tubotuberella rhombiformis Vozzhennikova, 1967, p.180, pl.101, figs.1a–b,2a–b; pl.102, figs.1,2a–b,3a–b; pl.104, figs.1–3.
Emendation: Brideaux, 1977, p.36. Holotype: Vozzhennikova, 1967, pl.101, figs.2a–b; pl.104, fig.2, lost according to Lentin and Vozzhennikova (1990, p.117–118).
Lectotype: Lentin and Vozzhennikova, 1990, pl.14, figs.1–2; text-fig.68, designated by Lentin and Vozzhennikova (1990, p.117). Contrary to the statements of Stover and Evitt (1978, p.197), Vozzhennikova (1967, p.180) cited only one specimen for the holotype. Lentin and Vozzhennikova (1990, p.117) provided an "expanded description" for this species.
Stratum typicum: Late Jurassic
Locus typicus: Well borings near Kuntsevo, well 15, Chulkovo, Moscow region, Russia
---------------------------------------------------------------------------------------------------
Translation Vozzhennikova, 1967: Lees in Sarjeant, 1971 (Ed.)
Original diagnosis: Vozzhennikova, 1967, p. 179-180
Theca rhomboid, somewhat drawn out ventrally. The lateral walls of the theca are convex and surround the large ovoid or elliptical internal body. Epitheca conical with a small apical process. Hypotheca gradually tapers towards the antapex and ends in a square opening. From the transverse furrow to the poles run smooth ribs which from trapeziform fields on the epitheca and on the antapical part of the hypotheca contribute towards the formation of a tetrahedral tapering tube. Transverse furrow shallow, annulate, its ends widely separated. The ribs running from the ends to the poles delimit a broad ventral field. The envelope of the internal body is thin, smooth and pale yellow in colour. Pylome rounded trapeziform with its lower edge almost touching the transverse furrow and the upper edge not far from the apical end of the theca.
Dimensions:
holotype - length 121.5 µm, breadth 64.8 µm, length of internal body 62.4 µm, breadth 59.5 µm, width of transverse furrow 8.1 µm.
In other specimens - length 83.7-94.5 µm, breadth 40.5-51.3 µm, length of internal body 43.2-54.0 µm, breadth 37.8-48.6 µm, width of transverse furrow 5.5-8.0 µm.
Emended description: Brideaux 1977, p. 36
As for the genus (emend. Brideaux 1977) with these particular features: the parasutaral ridges smooth and unornamented; the epipericoel conical in outline.
Expanded description: Lentin and Vozzhennikova, 1967, p.117
Cysts proximate, elongate ellipsoidal with one short apical horn and one long tetrahedral, tubular antapical projection; endocyst distinctly oval, with or without short apical horn; bicavate, hypocyst drawn out into a long posterior extension which is four-sited and open distally where the 1"""" paraplate appears to be absent. Paraphragm and endophragm smooth to minutely granulose; parasutural ridges are low and discontinuously outline paratabulation. Paratabulation gonyaulacacean, outlined by low ridges, formula: 3-4", 6"",?c, 5""", 1"""". The archeopyle is precingular (Type P, 3"" only), attached along the paracingular margin. Paracingulum indistinctly indicated by low ridges. Parasulcus not indicated or indicated only as a flat area on ventral hypocyst.
Size: Holotype, length 121 µm, width 65 µm; endocyst length 62 µm, width 59 µm; Lectotype length 123 µm. Range, length 83-125 µm, width 40-67 µm.
Affinities:
Lentin and Vozzhennikova, 1990, p.117: Tubotuberella rhombiformis most closely resembles T. apatela (Cookson and Eisenack) Ioannides et al., which does not have a paracingulum and has less well developed apical and antapical pericoels.