MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE OF POLAND 37
nerations (Text-fig. 4). The mega II generation has not been found. PD:
micro 20!l' mega I 70-160fl.
Ontogeny. - Only a few MS specimens have been found beside a large
number of QS ones. The massiline stage was probably rarely attained in
this species and mature individuals remained quinqueloculine. If we
expose the juvenile stage by removing the external chambers of a specimen
of "Quinqueloculina pauperata d'Orbigny" appearance, we receive
a form of Quinqueloculina akneriana d'Orbigny appearance. (Text-fig. 5).
lmm
@a
~b
Fig. 5. Quinqueloculina akneriana d'Orbigny and its juvenile stage, Lower Tortonian,
Wieliczka; 1 - MS; 2 - QS from inside MS; a front view, b apertural view.
The morphology of tests derived from the same sample indicates the
presence of transitional forms between Q. akneriana and "Q. pauperata"
(Text-fig. 3).
Remarks. - Our specimens are identical with the topotypes from
Baden, but differ somewhat from d'Orbigny's illustration from 1846 in
having a less rounded periphery. There is great morphological resemblance
and probably also a relationship in internal structure between Q. akneriana
and Q. triangularis d'Orbigny. Q. akneriana QS differs from Q. triangularis
QS in its more· slender shape and more distinct and depressed
sutures. The aperture shape and the internal structure are identical in
these species. The difference in the shape of tooth noted by d'Orbigny is
insignificant as both species may have either a simple or a bifid tooth.
The MS of both species is however indistinguishable, even in slightly
damaged specimens. The QS of the mega II generation of both species is
probably indistinguishable too, hence they are hard to identify. In spite
of this conformity the quinqueloculine stage of these two species can be
easily distinguished from each other on the basis of the test shape and
therefore they are not regarded here as synonyms, as they are by some
authors (e.g. Marks 1951, Verhoeve 1970). In the materials from Baden
(Sooss) and Wieliczka both species are common and they differ evidently
one from another. Both authors mentioned above synonymize a number
of other species of d'Orbigny, Reuss, Bornemann and even Q. seminulum