MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE OF POLAND 147
longitudinal wrinkles in gerontic specimens; wall thin; aperture large,
semicircular, oblique, with an everted border and a low, tape-shaped
tooth, sometimes with two angular corners.
Variability. The aperture may be semicircular and oblique or high and
nearly perpendicular to the periphery. The tooth may be partly or entirely
reduced, leaving the opening of the aperture empty (Text-fig. 52).
lmm
Fig. 52. Morphological variability and internal structure of Varidentella sarmatica
(Karrer), Lower Sarmatian, Zrecze-3 borehole, depth 101.9-102.0 m, micro (?) generation:
1 - irregularly triloculine chamber arrangement; 2 - irregularly quinqueloculine
chamber arrangement; 3 - quinqueloculine chamber arrangement; a front view,
b apertural view, c cross-section.
Dimorphism and ontogeny. The sections show the micro (?) generation,
PD 30-60 "". The internal structure is quinqueloculine or cryptoquinqueloculine.
The juvenile stage removed from the inside of the mature specimens
without a tooth in the aperture, show a broad tooth with two
corners, like that in Varidentella reussi (Bogdanowich).
Remarks. - This species differs from Varidentella reussi in the slenderer
test, semicircular, higher aperture and smooth, polished surface.
From V. latelacunata (Venglinsky) it differs in its narrower, less inflated
chambers and more flattened, not depressed sutures. The thorough examination
of the material from Nexing in the Vienna Basin I succeeded
in finding hardly 5 specimens of V. sarmatica, which correspond morphologically
to our specimens and have a transverse tape-shaped tooth in the
aperture. They differ however from V. reussi, which is easy to distinguish
in materials from Lower Sarmatian of Poland.
Distribution. - Poland: Lower Sarmatian, (Mach6w, Piaseczno, Rytwiany,
Zrecze). Austria: Lower Sarmatian, Nexing, Vienna.