MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE, -0F POLAND
69
Articularia karreriella (Venglinsky, 1958)
(PI. XVII, Figs 3, 4a, b, 5,6a-c)
1958. Miliolina karreriella Venglinsky; I. V. Venglinsky, p. 69, PI. 9, Figs 1, 2.
1958. Articulina (?) aff. kudakoensis Voloshinova; ibidem, p. 97, PI. 19, Figs 17, 18.
1961. Quinqueloculina karreriella Venglinsky var. articulata Venglinsky; I. V. Venglinsky,
p. 101, cum syn.
1968. Quinqueloculina karreriella var. articulata Venglinsky; B. Ionesi, p. 262, PI. 13,
Figs 16-19.
1971. Quinqueloculina electa Maissuradze; L. S. Maissuradze, p. 56, PI. 2, Fig. 2a-c.
Material. - Over 100 specimens (ColI. No. F-117).
Dimensions: Initial part: L 0.3-0.6; uniserial part L up to 1.
Description. - Initial part rhomboid-oval, chambers tubular in quinqueloculine
or cryptoquinqueloculine arrangement, bent in the lower part
at an angle of about 90 0
and covered with 6-7 irregular, longitudinal,
sometimes bifurcate or slightly oblique, distinct ribs; middle chamber
elongated, inflated, with 3-4 ribs; uniserial part composed of 2-3
chambers, which are strongly inflated in 1/3 of their height and narrowing
toward the end, covered with about 8 ribs partly bifurcated on the
inflated part of the chamber; sutures distinct, depressed; aperture of
the initial part semicircular or circular, with low quadrate tooth; that
of the uniserial part circular, small, without tooth.
Variability and ontogeny. The number and character of ribs are
variable, they may be bifurcated on the uniserial part or not, whereas
on the initial part they are often irregular and obliquely curved. The
uniserial part often falls away leaving no traces on the initial part, owing
to which this last part may be erroneously determined as Quinqueloculina.
Sometimes the first chamber of the uniserial part grows obliquely to the
coiling axis (PI. XVII, Fig. 5) and may have various positions, as in
Articularia articulinoides (Gerke & Issaeva).
Remarks. - Venglinsky (1958) noticed the resemblance of the initial
part of Articulina (?) aff. kudakoensis Voloshinova to Miliolina karreriella,
a quinqueloculine form determined by him from the same beds as A. aff.
kudakoensis and suggested that they are "varieties" of the same "articulina-like"
species of Quinqueloculina. Later (1961), basing himself on
this observation, he described this "variety" as Quinqueloculina karreriella
var. articulata, in its synonymy placing also the forms defined earlier
as Articulina aff. kudakoensis. Hence it follows that he still acknowledged
the two "varieties" of Quinqueloculina karreriella, one of which was quinqueloculine,
the other articuline. As he did not make himself clear as to
which of his "varieties" he considered to be a sucspecies and the author's
investigations show that both forms are only ontogenetical stages of the
same species, the older specific name "karreriella" has been retained.
The quinqueloculine stage differs from Cyclojorina karreri ovata (Scrova)
in lacking the short extension of the last chamber, in the less slender