MILIOLIDAE - Acta Palaeontologica Polonica

150 EWA LUCZKOWSKA
Sigmoilinita tschokrakensis (Gerke, 1938)
(PI. XVI, Figs sa, b, 9a, b)
1938. Sigmoilina tschokrakensis Gerke; A. A. Gerke, p. 308, PI. 3, Figs 1-18.
1952. Sigmoilina tschokrakensis Gerke; A. K. Bogdanowich, p. 161, PI. 23, Figs 6, 7;
cum syn.
1970. Sigmoilina tschokrakensis Gerke; O. Djanelidze, p. 107, PI. 16, Fig. la, c.
Material. -
30 specimens (ColI. No. F-199)
Dimensions: L 0.5-0.6; B 0.25-0.3; T 0.15-0.17
Description. - Test oval, tapering at both ends, flattened, in the central
part slightly convex, periphery rounded; chambers tubular with flattened
sides, 2-3 chambers of planispiral stage somewhat broader than those
of sigmoiline stage in the centre of the test; sutures depressed; surface
smooth, dull; aperture small, circular, at the end of a short neck and with
a short, simple tooth.
Variability and ontogeny. The shape of the test is very variable, according
to the description of Gerke. Juvenile specimens are slenderer, the
mature ones are broader and flat.
Remarks. - This species differs from Sigmoilinita tenuis (Czjzek) and
S. tenuissima (Reuss) in its broader, tubular chambers, more compact test,
convex in the central part and dull wall. It is similar to Sigmoilina elliptica
Galloway & Wissler, Pleistocene, but differs in the more elongate test
and in the presence of a tooth in the aperture.
Distribution. - Poland: Tortonian (Grabki Duze, Korytnica, Wieliczka).
USSR: Tortonian, the Crimea-Caucasian region.
Material. -
Sigmoilinita sp.
(PI. XVI, Fig. 7a-c)
1 specimen (ColI. No. F-200).
Dimensions: L 0.72; B 0.4; T 0.15
Description. - Test quadrangular-oval, flat, periphery rounded; chambers
tubular, thick, somewhat bent at the base and straight near the
aperture, two last chambers arranged in a single plane, three middle
chambers of sigmoiline stage in test centre; sutures depressed, distinct;
wall matt; aperture circular, at the end of a short neck, surrounded with
a thickened rim and having a short and simple tooth.
Remarks. - No mention of this form has been found in the literature
available to the author; it is however so distinct and well preserved, that
it has been decided to state its presence only.
Distribution. - Poland: Upper Tortonian (Krywald).