MILIOLIDAE - Acta Palaeontologica Polonica

34 EWA :LUCZKOWSKA
orthogenetic development here, for the direction of development of these
forms with time has not been examined. In this case the intermediate
forms between the genera Quinqueloculina and Massilina, visible in the
sections, have contributed to the recognition of the genus Massilina as
synonymous with Quinqueloculina and representing only its ontogenetic
stage (MS).
There are also species with intermediate characters between the genera
Quinqueloculina and Varidentella, Varidentella and Cycloforina, Cycloforina
and Sinuloculina, and between Miliolinella and Pyrgoella. For instance,
Quinqueloculina regularis and Q. pygmaea, with a typically quinqueloculine
internal structure, have a lower aperture and a shorter tooth,
just as in Varidentella (Text-fig. 21); Varidentella rosea, which has
a subcircular aperture like that in Cycloforina, in its internal structure
shows a turn of the coiling axis, as in Varidentella (Text-fig. 50); Sinuloculina
consobrina and S. nitens, whose initial stage is a quinqueloculine
one and the shape of aperture like that in Cycloforina, in the adult stage
have only 3 chambers seen from the outside, as in Sinuloculina (Text-figs
40, 43); Miliolinella valvularis, in rare adult forms of which the last two
chambers cover the preceding ones as in Pyrgoella, has a cryptoquinqueloculine
internal structure like Miliolinella (Text-fig. 37).
The foregoing examples indicate that there are difficulties in the
classification of the Miliolidae also within the taxonomic unit proposed.
An investigation of the genetic relationships between the species belonging
to particular genera would presumably diminish these difficulties, but
such investigation is possible only when based on evolutionary series, as
in Hofker's case. It, however, goes beyond the scope of the present
work and makes the subject for a separate publication. The examples
chosen do not exhaust the problem. Here the author wants only to signal
the existence of problems connected with the presence of intermediate
forms between genera and the necessity of further studies on the phylogenetic
development of miliolid species.
SYSTEMATIC PART
DESCRIPTION OF SPECIES
Suborder Miliolina Delage & Herouard, 1896
Superfamily Miliolacea Ehrenberg, 1839
Family Miliolidae Ehrenberg, 1839
Subfamily Quinqueloculininae Cushman, 1917, emend Luczkowska, 1972
Genus Quinqueloculina d'Orbigny, 1826, emend Luczkowska, 1972
Studies on the internal structure and ontogeny of various species of
the Miocene Miliolidae have shown (Luczkowska, 1972) that in the genus