MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE OF POLAND 35
Quinqueloculina we should include forms with the following morphological
features: 5 or more chambers visible from outside; oval, elongated
aperture with a long simple or bifid tooth; chambers with a floor in the
adult; last chambers of the adults of most species added in a single plane.
There are three exceptions among the Miocene species: Quinqueloculina
spondiungeriana, Q. pygmaea and Q. regularis, the massiline stage of
which has not been found. The first of them has a typical aperture with
a simple tooth but the other two show a non-typical, semicircular or triangular
opening and a broad tape-shaped tooth. It may well be that these two
species belong to another genus or they are transitional forms between
the genera Quinqueloculina and Varidentella, to which they approximate
in having a short broad tooth. They cannot however be assigned to the
genus Varidentella, because they have not a cryptoquinqueloculine
internal structure nor does their coiling axis turn in the ontogeny.
X Quinqueloculina akneriana d'Orbigny, 1846
(Pl. VIII, Figs 1a-c, 2a, b, 3a, b; Text-figs 3-5)
1846. Quinquelaculina aknerialla d'Orbigny; A. d'Orbigny, p. 290, PI. 18,
Figs. 16-21.
1846. Quinquelaculina pauperata d'Orbigny; ibidem, p. 286, PI. 17, Figs 22-24.
1950b. Milialina akneriana (d'Orbigny); A. K. Bogdanowich, p. 145, PI. 1, Fig. 10.
1952. Milialina akneriana (d'Orbigny); A. K. Bogdanowich, p. 111, PI. 10, Fig. 5.
non 1955. Miliolina akneriana (d'Orbigny); M. J. Serova, p. 304, PI. 2, Figs 1-3.
1956. Quinqueloculina akneriana d'Orbigny; A. Sulimski, p. 82, PI. 4, Figs 4-8.
1961. Quinquelaculina akneriana d'Orbigny var. akneriana d'Orbigny; V. I. Didkovsky,
p. 34, PI. 5, Fig. 6.
1970. Quinquelaculina akneriana d'Orbigny; D. Verhoeve, p. 26, PI. 1, Figs 4, 5.
Material. 1) - About 100 QS and 20 MS (CoIl. No. F-101, Sec. No.
143-147, 254, 320, 321, 329-331).
Dimensions: 2) QS - L 0.8-1.1; B 0.55-0.75; T 0.4-0.6; MS - L
1.5-2.5; B 1.1-1.9; T 0.5-0.85.
Description. - QS oval, slender, tapering at both ends, high and triangular
in transverse section, periphery subacute; chambers narrow, with
flattened sides, middle chamber elongate, large, convex, fifth chamber
clearly visible; MS flat, oval in outline, periphery broadly rounded;
chambers broad, middle chamber small, oval, narrowing at both ends;
sutures distinct, slightly depressed; wall in QS thin, in MS thickened;
surface smooth, polished; aperture oval with a long simple or bifid tooth.
Variability. The test shape varies from oval to narrowly oval, the
periphery may be more or less rounded (Text-fig. 3). A characteristic
1),2) The numbers indicate the amount of specimens; the abbreviations used are
as follows: QS - quinqueloculine stage, MS - massiline stage, ColI. No. - collection
number, Sec. No. - section number, L -length, B - breadth, T - thickness. Dimensions
are given in mm.