Recent investigations on the microfauna at the Badenian / Sarmatian boundary (Middle Miocene) showed interesting characters of the Anomalinoides dividens foraminifera assemblages. Several taxonomic aspects are considered in order to clarify the meaning of different stratigraphic approaches. A possible planktonic or pseudo-planktonic life of the species is suggested by micropaleontologic, paleogeographic and paleoenvironmental data

Filipescu, Sorin

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Anomalinoides dividens bioevent at the Badenian/Sarmatioan boundary – a response to paleogeographic and paleoenvironmental chnages

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STUDIA UNIVERSITATIS BABEŞ-BOLYAI, GEOLOGIA, XLIX, 2, 2004, 21-26 
 
 
                                                          
ANOMALINOIDES DIVIDENS BIOEVENT AT THE BADENIAN / 
SARMATIAN BOUNDARY – A RESPONSE TO PALEOGEOGRAPHIC 
AND PALEOENVIRONMENTAL CHANGES 
 
 
SORIN FILIPESCU1
 
ABSTRACT. Recent investigations on the microfauna at the Badenian / Sarmatian 
boundary (Middle Miocene) showed interesting characters of the Anomalinoides dividens 
foraminifera assemblages. Several taxonomic aspects are considered in order to clarify 
the meaning of different stratigraphic approaches. A possible planktonic or pseudo-
planktonic life of the species is suggested by micropaleontologic, paleogeographic and 
paleoenvironmental data. 
 
Keywords: foraminifera, Middle Miocene, Paratethys, paleoecology, biostratigraphy 
 
 
 
 
INTRODUCTION 
Anomalinoides dividens a foraminifer species described by Łuczkowska (1967) 
is considered as an index taxon for the regional biostratigraphy of the Paratethyan 
area. Its acme characterizes the base of the Sarmatian; therefore the Anomalinoides 
dividens Biozone was introduced in order to trace the boundary between Badenian 
and Sarmatian deposits. 
Recent sedimentologic and micropaleontologic investigations showed new 
possibilities to interpret the paleoenvironmental conditions around the Badenian / 
Sarmatian boundary.    
 
MATERIAL AND METHODS 
Most of the studied specimens of Anomalinoides dividens come from the 
micropaleontological collection of Romgaz S.A. Mediaş, now in the custody of the 
Department of Geology of Babeş-Bolyai University. The specimens were collected 
from exploration wells drilled during the last decades in the Transylvanian Basin. 
Individual specimens were studied by using the JEOL JSM 5510LV scanning 
electron microscope in the Department of Biology, Babeş-Bolyai University. The 
micropaleontological record was correlated with sedimentological data gathered 
from cores, well logs and seismic profiles (Krézsek & Filipescu, in press). 
 
ANOMALINOIDES DIVIDENS ASSEMBLAGES 
According to the description of Łuczkowska (1967), the test of Anomalinoides 
dividens is “low trochospiral, circular, lobulate, periphery broadly rounded, especially in 
the last part of the whorl. Spiral side convex with the slightly depressed central part, 
1 Babeş-Bolyai University, Department of Geology. Str. Kogălniceanu 1, 400084 Cluj-Napoca, Romania. 
e-mail: sorin@bioge.ubbcluj.ro 
SORIN FILIPESCU 
 
 
last whorl broad with 7-10 inflated chambers, enlarging rapidly as added, earlier 
whorls small and slightly visible in the middle of the depressed part, often covered 
with thickened shell material, sutures oblique, arcuate. Opposite side involute, 
umbilicate, few last chambers strongly inflated, triangular, sutures radial. Wall thin, 
transparent, smooth, densely perforated, especially on the spiral side, the umbilical 
side with earlier part more sparsely perforated or nearly devoid of pores, granular 
in structure… Aperture peripheral, large, semicircular, with slightly thickened lip, 
extending onto the spiral side”. 
Intraspecific variations of test morphology are very common for the 
Anomalinoides dividens populations (test size and outline, last chamber size and 
shape, perforation patterns, etc. – see plate 1). As a consequence, several names 
have been used for the same species: 
• Anomalina grosserugosa Gümbel sp. Brady, 1884, pl. 94, figs. 4,5; 
• Cibicides certus Venglinski, 1953, pl. 5, fig. 10-12;  
• Cibicides (Anomalinoides) pokuticus Aisenstat, 1954, pl. 24, fig. 3 (In: 
Vasilenko, 1954); 
• Cibicides (Anomalinoides) kaluschiensis Aisenstat, 1954, , pl. 24, fig. 4 
(In: Vasilenko, 1954); 
• Cibicides (Anomalinoides) postkarpaticus Aisenstat, 1954, pl. 24, fig. 5 
(In: Vasilenko, 1954); 
• Cibicides (Anomalinoides) transkarpaticus Pishvanova, 1954, pl. 24, fig. 
6 (In: Vasilenko, 1954); 
• Cibicides menneri Serova, 1955, pl. 26, figs. 6-8 
• Cibicides predcarpaticus Aisenstat, 1955, pl. 28, figs. 3-5 (In: Serova, 1955) 
• Anomalinoides dividens Łuczkowska, 1967, pl. 9, figs. 1-8 
Although it has no priority, using the name given by Łuczkowska is preferred 
because of the detailed description and illustration of the species. 
A few other confusions were done along time: 
1. The species was erroneously diagnosed as “Cibicides lobatulus”, the 
type species of the genus Lobatula (e.g. Costea & Balteş, 1962; Paghida-Trelea, 
1969).  Cibicides lobatulus (Walker & Jacob) has a flat to irregular spiral side 
showing thickened sutures, with carinate periphery (see also Loeblich & Tappan, 
1988) and these diagnostic features do not conform with the diagnosis of the genus 
and species in discussion (Plate I).  
2. The species was sometimes cited as “Cibicides badenensis” or “Anomalinoides 
badenensis” (e.g. Brestenská, 1974), a typical species for the “upper lagenide zone” of 
the Badenian. According to Papp & Schmid (1985) d’Orbigny’s species Anomalina 
badenensis has a small, radiate-oval aperture and an ornamented test and differs 
from the species cited from the Sarmatian. 
 
DISCUSSIONS 
Popescu (1995) considered that the replacement of the Badenian marine 
faunas with brackish assemblages at the boundary with the Sarmatian could be 
associated with a global cooling event. This hypothesis is weakly supported both 
by the global context and the transgressive pattern of sedimentation associated to 
the Anomalinoides acme (Krezsek & Filipescu, in press). 
 22 
ANOMALINOIDES DIVIDENS BIOEVENT AT THE BADENIAN / SARMATIAN BOUNDARY 
 
 
The “total isolation” of the Paratethyan area at the end of Badenian was a 
widely accepted working hypothesis until recent decades (e.g. Rögl, 1985, 1998). 
Sedimentologic and micropaleontologic data (Krezsek & Filipescu, in press) suggest 
the existence of connections of the Transylvanian Basin to the open seas, at least 
during the Early Sarmatian. The transgression initiated around the Badenian / Sarmatian 
boundary occurred during global highstand conditions (see Haq et al., 1988). Probably 
the switch to the brackish environments produced due to the interference with the 
tectonic evolution of the Carpathians during the Late Badenian, which restricted the 
communications to the open seas. This produced water stratification, with a surface 
brackish layer (supplied by the increased influx of continental water) and an oxygen-
depleted deeper layer (a situation analogous to the modern-day Black and Marmara 
seas).  
The unidirectional circulation of the surface waters severely restricted the 
migration of the normal marine planktonic faunas from the open seas to the 
Paratethyan basins. Just a few small globigerinids can be found in the lowermost 
Sarmatian sediments. In such transgressive conditions, with stratified waters, the 
massive occurrence of endemic populations with Anomalinoides dividens needs to 
be reconsidered. Although it is considered a benthic species, its behavior (spectacular 
bloom), test structure and exclusive association with small planktonic species, 
suggests at least a pseudo-planktonic way of life. 
As shown in Plate I, fig. 9, the wall structure of the test is bilamellar, a 
typical feature of planktonic foraminifera. Its morphologic characters are not far 
from non-spinous, herbivorous, symbiont barren planktonic species. An alternative 
to the supposed planktonic life could be its pseudo-planktonic behavior, temporarily 
attached to the floating algae with the spiral side of the test. 
Rare small globigerinids (Globigerina praebulloides, G. tarchanensis, G. 
subcretacea), that occur together with Anomalinoides in the deep marine sediments at 
the Badenian / Sarmatian boundary, were the only typical planktonics able to tolerate 
the lowered salinity. In such conditions, the ecologic place of the globigerinids was 
rapidly taken by the endemic Anomalinoides dividens. 
The transgressive setting at the Badenian / Sarmatian boundary places the 
Anomalinoides dividens acme in a well-defined position within the sequence stratigraphic 
interpretations. As a consequence of subsequent strong endemization of the Paratethyan 
faunas, Anomalinoides dividens Biozone might be the last confident biozone preceding 
the ecozones in use for the remaining Miocene.  
 
 
CONCLUSIONS 
The Anomalinoides dividens bioevent represents a valuable biostratigraphic 
marker with implications in sequence stratigraphic studies. Its occurrence in transgressive 
settings, together with smaller globigerinids, shows a similar behavior to the planktonic 
assemblages. The planktonic or pseudo-planktonic life of the species was probably 
determined by the paleoenvironmental setting, with stratified water column which 
suppressed most of the benthic life and stimulated the faunas in the upper, well 
oxygenated, water body. 
 23
SORIN FILIPESCU 
 
 
Acknowledgements 
The author is grateful to S.N.G.N. Romgaz S.A. Mediaş for providing access to 
the studied material and to Dr. Michael A. Kaminski for reviewing the manuscript.  
This is a contribution to the 169 Romgaz and 28/180 C.N.C.S.I.S. research 
grants. 
 
 
REFERENCES 
 
Brady, H.B., 1884. Report on the foraminifera collected by H.M.S. Challenger during the years 
1873-1876. Reports on the Scientific results of the voyage of H.M.S. Challenger. Zoology, 
Edinburgh. 9, 814 pp. 
Brestenská, E., 1974. Die Foraminiferen des Sarmatien s.str. Chronostratigraphie und Neo-
stratotypen, M5 Sarmatien, Bratislava. 243-293. 
Costea, I, & Balteş, N., 1962. Corelări stratigrafice pe baza microfosilelor. Editura Tehnică Bucureşti. 
263 pp. 
Haq, B. U., Hardenbol, J., Vail. P. R., 1988. Mesosoic and Cenozoic chronostratigraphy and 
cycles of sea level changes. In: C. K. Wilgus, B. S. Hastings, C. G. St. C. Kendall, H. W. 
Posamentier, C. A. Ross, J. C. Van Wagooner (Editors). Sea-level changes - an integrated 
approach, SEPM Special Publication 42, 71-108. 
Krézsek & Filipescu, in press. Middle to Late Miocene Sequence Stratigraphy of the 
Transylvanian Basin (Romania). In: Cloetingh, S., Dinu, C., Maţenco, L., Mocanu, V., Bada, 
G. (eds.) - Carpathian / Pannonian System. Tectonophysics Special Issue. Elsevier. 
Loeblich, A.R., Tappan, H., 1988. Foraminiferal Genera and Their Classification. Van Nostrand 
Reinhold Co. New York. 970 pp 
Łuczkowska, E., 1967. Some new species of Foraminifera from the Miocene of Poland.  Rocznik 
Polskiego Towarzystwa Geologicznego, Krakow. 37/2, 233-241.. 
Paghida-Trelea, N., 1969. Microfauna Miocenului dintre Siret şi Prut. Editura Academiei RSR 
Bucureşti. 190 pp. 
Papp, A., Schmid, M.E., 1985. The Fossil Foraminifera of the Tertiary Basin of Vienna. Revision 
of the Monograph by Alcide d'Orbigny (1846). Abhandlungen der Geologischen Bundesanstalt, 
Wien, 37, 107 pp. 
Rögl, F., 1985. Late Oligocene and Miocene Planktic Foraminifera of the Central Paratethys. În: 
Bolli, H.M., Saunders, J.B., Perch-Nielsen, K. (eds.) - Plankton Stratigraphy. Cambridge 
University Press. 315-328. 
Rögl, F., 1998. Paratethys Oligocene - Miocene Stratigraphic Correlation. In: Cicha, I, Rögl, F., 
Rupp, C., Ctyroka, J. (eds.), Oligicene to Miocene foraminifera of the Central Paratethys. 
Abhhandlungen der senckbergishen naturforschenden Gesellschaft, Frankfurt am Main. 549, 
3-7. 
Serova, Y., 1955. Stratigrafiya i fauna foraminifer Miotzenov’ikh otlozhenii Predkarpat’ya. In: 
Material’i po biostratigrafii zapadn’ikh oblastei Ukrainskoi SRR, Moskva. 261-458. 
Vasilenko, V.P., 1954. Anomalinidy. Iskopaemye Foraminifery SSSR. Trudy VNIGRI, Leningrad. 
80, 282 pp. 
Venglinski, I.V., 1953. O Mikropaleontologycheskyh issledovan’iakh srednemiotzenov’ikh otlozhenii 
Verhnetissenskoi vpadiny Zakarpatskoi oblasti. Trudy L’vovsk. geol. ob-va paleont. seriya 2, 
144 pp. 
 
 
Plate I - Specimens of Anomalinoides dividens Łuczkowska from the Sarmatian of the Transylvanian 
Basin (scale bar 100 µm): 1-3 Spiral view (1,2 Well 14 Ţelina; 3 Well 11 Fântânele); 4-
6 Umbilical view (4,6 Well14 Ţelina; 5 Well 11 Fântânele); 7-9 Apertural view (Well 
14 Ţelina; arrow on specimen 9 shows bilamellar wall); 10 Twin specimens (Well 
14 Ţelina); 11, 12 Morphologic variations of the test (Well 11 Fântânele). 
 24 
ANOMALINOIDES DIVIDENS BIOEVENT AT THE BADENIAN / SARMATIAN BOUNDARY 
 
 
Plate I 
 
 
 25


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Anomalinoides dividens bioevent at the Badenian/Sarmatioan boundary – a response to paleogeographic and paleoenvironmental chnages

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