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Smolenskiella crassitheca
Smolenskiella crassitheca Vozzhennikova, 1967, p.182–183, pl.105, figs.1a–b,2,3a–b,4,6; pl.106, figs.1–4; text-figs.17a–b. Emendation: Lentin and Vozzhennikova, 1990, p.64–65.
Holotype: Vozzhennikova, 1967, pl.105, fig.4, pl.106, fig.4; Lentin and Vozzhennikova, 1990, pl.8, figs.1-3, text-fig.35
Locus typicus: Smolensk Region, Russia
Stratum typicum: Late Cretaceous
Translation Vozzhennikova, 1967: Lentin and Vozzhennikova, 1990
Original description: Vozzhennikova, 1967, p.182-183
Theca thick walled, divided by a narrow, deep, annulate or slightly spiral transverse furrow into two parts - a larger epitheca and a smaller hypotheca. The epitheca is bell-shaped with a short apical horn, truncated at the distal end. On its ventral side is situated a narrow apical plate (1st) with the 2nd and 4th apical plates lying on either side. The first apical plate lies below the 2nd and below the 4th are the 5th ant 6th anterior equatorial plates, of which the 6th is small and barely discernible. (fig. 17A). On the dorsal side is the 3rd apical plate which makes contact with the three intercalaries. The pylome takes the place of the second intercalary plate. Between the transverse furrow and the intercalary plates are the 2nd, 3rd and 4th anterior equatorial plates of which, the third is considerably smaller than the others and is almost square (fig.17B). Hypotheca trapeziform, sualler than the epitheca, with a straight apical margin. On the ventral side of the hypotheca lie the 1st and 5th posterior equatorial and two intercalary plates, the latter making contact with the longitudinal furrow and the antapical plate. On the dorsal side are the large 2nt, 3rd and 4th posterior equatorial plates. The longitudinal furrow is narrow and extends from the first apical plate on the epitheca to the intercalary plates on the hypotheca. The margins of the plates and transverse furrow are bordered with low, narrow crests. The internal body is ovoid, thin-wal1ed and sometimes has a small horn at the apical end and a rounded antapical end. Surface of internal body and theca smooth.
Emended description: Lentin and Vozzhennikova, 1990, p.65
Cyst shape roundly peridinioid; epicyst slightly domeshaped with a small blunt apical horn; hypocyst broadly rectangular, without horns; endocyst small, oval, with or without small apical horn; circumcavate. Periphragm thin, finely granulose; endophragm smooth, thicker than periphragm. Paratabulation indicated by distinct parasutural ridges on periphragm; peridinioid. Peri- and endoarcheopyle standard hexa (isodeltafor-) formed by the loss of the 2a paraplate in both wall layers. Paracingulum is shallow, distinctly bortered by parasutural ridges and divided into 4-5 rectangular paraplates. Parasulcus is shallow, bordered by distinct parasutural ridges.
Size: Holotype, length 43 µm, width 36 µm, width of paracingulum 3-4; length of endocyst 28 µm, width 24 µm. Range, length 40-48 µm, width 33-37 µm; length of endocyst 25-34 µm, width 20-24 µm.
Holotype: Vozzhennikova, 1967, pl.105, fig.4, pl.106, fig.4; Lentin and Vozzhennikova, 1990, pl.8, figs.1-3, text-fig.35
Locus typicus: Smolensk Region, Russia
Stratum typicum: Late Cretaceous
Translation Vozzhennikova, 1967: Lentin and Vozzhennikova, 1990
Original description: Vozzhennikova, 1967, p.182-183
Theca thick walled, divided by a narrow, deep, annulate or slightly spiral transverse furrow into two parts - a larger epitheca and a smaller hypotheca. The epitheca is bell-shaped with a short apical horn, truncated at the distal end. On its ventral side is situated a narrow apical plate (1st) with the 2nd and 4th apical plates lying on either side. The first apical plate lies below the 2nd and below the 4th are the 5th ant 6th anterior equatorial plates, of which the 6th is small and barely discernible. (fig. 17A). On the dorsal side is the 3rd apical plate which makes contact with the three intercalaries. The pylome takes the place of the second intercalary plate. Between the transverse furrow and the intercalary plates are the 2nd, 3rd and 4th anterior equatorial plates of which, the third is considerably smaller than the others and is almost square (fig.17B). Hypotheca trapeziform, sualler than the epitheca, with a straight apical margin. On the ventral side of the hypotheca lie the 1st and 5th posterior equatorial and two intercalary plates, the latter making contact with the longitudinal furrow and the antapical plate. On the dorsal side are the large 2nt, 3rd and 4th posterior equatorial plates. The longitudinal furrow is narrow and extends from the first apical plate on the epitheca to the intercalary plates on the hypotheca. The margins of the plates and transverse furrow are bordered with low, narrow crests. The internal body is ovoid, thin-wal1ed and sometimes has a small horn at the apical end and a rounded antapical end. Surface of internal body and theca smooth.
Emended description: Lentin and Vozzhennikova, 1990, p.65
Cyst shape roundly peridinioid; epicyst slightly domeshaped with a small blunt apical horn; hypocyst broadly rectangular, without horns; endocyst small, oval, with or without small apical horn; circumcavate. Periphragm thin, finely granulose; endophragm smooth, thicker than periphragm. Paratabulation indicated by distinct parasutural ridges on periphragm; peridinioid. Peri- and endoarcheopyle standard hexa (isodeltafor-) formed by the loss of the 2a paraplate in both wall layers. Paracingulum is shallow, distinctly bortered by parasutural ridges and divided into 4-5 rectangular paraplates. Parasulcus is shallow, bordered by distinct parasutural ridges.
Size: Holotype, length 43 µm, width 36 µm, width of paracingulum 3-4; length of endocyst 28 µm, width 24 µm. Range, length 40-48 µm, width 33-37 µm; length of endocyst 25-34 µm, width 20-24 µm.