Werner E. Piller

Circum-Mediterranean Oligo–Miocene biogeographic evolution – the gastropods’ point of view

Based on studies in Iran (Qom Basin, Esfahan^Sirjan Basin, Zagros Mountains), in Turkey (Mut and Sivas basins), in the Mesohellenic Basin, and in northeastern Egypt, a new palaeobiogeographic concept for the Oligocene and Miocene in the circum-Mediterranean area with special emphasis on the distribution patterns of gastropod faunas is presented.A very strict biogeographic terminology is proposed to avoid the common fusion of geographic, faunistic and geodynamic terms in the palaeontologists’ jargon.Our main interest focuses on the affinities and the faunistic interactions between the early ‘Mediterranean’ and the early ‘Indo-Pacific’ regions during the Oligo^Miocene. Especially the role of the early Indo-Pacific faunas as the mythic centre of origination of Early Neogene European mollusc faunas, as often vaguely indicated in the literature, is critically evaluated.This leads to the establishment of a Mediterranean^Iranian Province and a Western Indian^Eastern African Province as palaeobiogeographic subunits of the Western Tethys Region during the Oligocene.Due to major geodynamic and related biogeographic changes in the Early Miocene the Western Tethys Region no longer existed and was replaced by the Proto-Mediterranean^Atlantic Region.For the area of the Paratethys the palaeobiogeographic unit Danubian Province, which includes the ProtoCaspian Subprovince, is proposed.Furthermore, the underrated transatlantic communication of the Oligo^Miocene nearshore mollusc faunas is demonstrated.Altogether this paper is a contribution to the discussion on the biogeographic concepts, classification and nomenclature in palaeontology as initiated by Westermann [Palaeogeogr.Palaeoclimatol.Palaeobiogeogr.158 (2000) 1^13; 163 (2000) 49^68]. @ 2002 Elsevier Science B. V.All rights reserved.

Coral frameworks revisited+reefs and coral carpets in the northern Red Sea

Abstract Coral communities were investigated in the northern Red Sea, in the Gulfs of Suez and Aqaba, for their framework building potential. Five types of coral frameworks were differentiated: Acropora reef framework, Porites reef framework, Porites carpet, faviid carpet, and Stylophora carpet. Two non-framework community types were found: the Stylophora-Acropora community, and soft coral communities. Reef frameworks show a clear ecological zonation along depth and hydrodynamic exposure gradients, with clear indicator communities for each zone. By definition, coral carpets build a framework but lack distinct zonation patterns since they grow only in areas without pronounced gradients. In the northern Red Sea they show a gradual change with depth from Porites to faviid dominance. A Stylophora carpet is restricted to shallow water in the northern Gulf of Suez. Although growth rates of carpets may be somewhat less than those of reefs, the carbonate accumulation is considered to be higher in carpet areas due to their significantly higher areal extension. In addition, reefs and carpets have different sediment retention characteristics – the carpet retains, the reef exports. The in situ fossilization potential of coral carpets is expected to be higher than that of reef frameworks.

Biostromal Coral Facies—A Miocene Example from the Leitha Limestone (Austria) and its Actualistic Interpretation

Abstract Coral-rich strata of the Leitha Limestone of Badenian age (Middle Miocene) at the type-locality in Grosshoeflein (Burgenland province, Austria) were re-interpreted from an actualistic viewpoint in comparison with Recent Bahamian and Arabian Gulf coral communities. The investigated outcrop (quarry “Fenk”) is interpreted as a sequence of framebuilding coral carpets and non-framebuilding biostromal coral communities, alternating with bryozoan and corallinacean calcarenites and bivalve beds. No indication for the presence of a reef was found. In total, a sequence of 10 coral intervals was observed, which can be grouped into 2 coral carpet types (high carpet framework, low bushy framework), four non-framework communities, and one bivalve/coral community. Within this sequence, no unequivocal indication for sea-level changes at the time of deposition was apparent. The different coral facies are interpreted as having been deposited within roughly the same water depth as Recent coral systems observed in the Bahamas (Andros, Exuma Cays) and the Arabian Gulf (Dubai, UAE). According to the model presented, the facies merely represent different lateral positions within the same spatially highly complex environment. A distribution map of benthic biota in the Arabian Gulf (Jebel Ali, Dubai, UAE) was used to illustrate the likely lateral distribution of the Miocene facies.

Application of neontological taxonomic concepts to Late Eocene coralline algae (Rhodophyta) of the Austrian Molasse Zone

Traditionally, different diagnostic characters have been used in the identification of fossil and Recent coralline algal genera. The taxonomy of fossil coralline algae has focused on well calcified features such as basal filaments and conceptacle perforation. In contrast, the taxonomy of Recent material uses a combination of several features with a low fossilization potential, such as epithallial cells and structures of sexual reproductive organs. In the studied material of the Late Eocene Austrian Molasse Zone Lithoporella, Neogoniolithon, Spongites, Phymatolithon and Sporolithon are identified and described applying features of neontological taxonomic concepts. These features are: (1) the arrangement of basal filaments; (2) the occurrence of cell fusions; (3) the relative length of subepithellial initials; (4) the conceptacle perforation; (5) the orientation of filaments around the conceptacle pore; and (6) the type of conceptacle roof formation. Some of these features were thought to be unpresentable in fossil material until recently. The fossilization potential of diagnostic features and the identification of the documented genera and species are discussed in detail. Moreover, a checklist for the description of fossil taxa is provided.

Reefs and coral carpets in the northern Red Sea as models for organism-environment feedback in coral communities and its reflection in growth fabrics

Abstract Coral framework construction and resultant growth fabrics in response to environmental factors were studied in the northern Red Sea, and the Gulfs of Suez and Aqaba. The dependence of growth fabric types on sea-floor topography, oceanography and the ecology of constituent coral species was investigated. Five types of coral frameworks and their growth fabrics were differentiated: Acropora reef framework (platestone to mixstone facies); Porites reef framework (domestone facies); Porites carpet (columnar pillarstone facies); faviid carpet (mixstone facies); Stylophora carpet (thin pillarstone facies). Two non-framework community types were found: Stylophora-Acropora community and soft coral communities. Reef frameworks and resultant growth fabrics show a clear ecological zonation along depth and hydrodynamic exposure gradients. Coral carpets build a framework lacking a distinct internal zonation since they only grow in areas without pronounced gradients. In the northern Red Sea they show a gradual change with depth from Porites (pillarstone) to faviid (mixstone) dominance. The initiation of frameworks was governed by bottom topography (reefs on steep slopes and highs, coral carpets in flat areas). According to environmental conditions, different coral communities produce different framework and growth fabric types. In step with framework growth the environment is modified. The modified environment in turn modifies the coral communities. Thus an environment-organism-environment feedback loop exists.

Molecular phylogeny of large miliolid foraminifera (Soritacea Ehrenberg 1839)

Abstract The foraminiferal superfamily Soritacea belongs to the suborder Miliolina and is divided in two families, Peneroplidae and Soritidae, the latter one comprising two subfamilies, Archaiasinae and Soritinae. Phylogenetic relationships of 11 genera of soritid foraminifera were investigated by sequencing the complete SSU rDNA gene for 25 specimens. Additionally, partial SSU rDNA sequences were obtained from another 15 specimens of Soritinae. DNA sequence analysis confirms the monophyly of each family. Caribbean Archaiasinae form a monophyletic clade with Pacific Laevipeneroplis at the base. The genus Parasorites apppears as a sister taxa to Soritinae. Complex morphological features that characterize the genus Marginopora seem to have evolved independently at least twice, as the examined representatives cluster within two other soritine genera. Molecular analysis further shows that Sorites orbiculus and Sorites marginalis represent two different morphotypes of one species. Our data indicate that morphological changes and acquisition of new endosymbiont types in each group played an important role in the adaptation and radiation of Soritacea.

Palaeoenvironmental reconstructions by stable isotopes of Middle Miocene gastropods of the Central Paratethys

The stable isotopes of carbon and oxygen were used to provide information of mixing of marine and freshwater and subsequently used to determine palaeosalinities. In the Middle to Late Miocene St. Margarethen bZollhausQ section (Upper Sarmatian bMactra ZoneQ/Pannonian), a succession of three gastropod assemblages indicates changing environmental conditions from a limnic-fluviatile to littoral mudflat and a sublittoral marine environment. Several shells of the main representatives of the three assemblages [Potamides hartbergensis (Hilber), Granulolabium bicinctum (Brocchi), Potamides disjunctus (Sowerby)], and additionally shells of Lymnaea sp., a typical freshwater gastropod, and Pomatias conicus, a terrestrial gastropod, were taken for stable isotope analyses. Oxygen and carbon isotope data of the freshwater endmember are distinctively lower (dO~ 4.5x/dC~ 9x) than of the marine endmembers (dO~ 2.2x/dC~2.3x). In contrast to the expected intermediate isotopic composition between the freshwater and marine environment, the shells of supposed brackish environments have higher dO values than the shells of the marine environment. These higher dO values are explained by evaporation, which affected the protected areas of riverine to lacustrine environments and small pools on mudflats, formerly considered to be the habitats of the brackish assemblages. Thus, the oxygen and carbon isotope data extend the already existing palaeoenvironmental information. D 2004 Elsevier B.V. All rights reserved.

Lower and Middle Miocene biostratigraphy, Gulf of Suez, Egypt based on dinoflagellate cysts and calcareous nannofossils

This is the first detailed stratigraphic correlation of Lower and Middle Miocene deposits in the Gulf of Suez, Egypt using dinoflagellate cysts. The correlation is based on 273 ditch-cutting samples from five onshore boreholes located along the southwestern margin of the Gulf of Suez. The interval studied is represented by the Nukhul, Rudeis and Kareem formations of the Gharandal Group, and the lower part of the Belayim Formation of the Ras Malaab Group. These Miocene deposits unconformably overlie the Lower or lower Middle Eocene. The dinoflagellate cyst record is more diverse than previously reported and many taxa are documented for the first time in Egypt. Five biozones are established and tied to a chronostratigraphic framework by calibration to calcareous nannofossils (NN biozones) obtained from the same set of samples: (1) Lingulodinium machaerophorum Assemblage Biozone (GOSl), Aquitanian through mid-Burdigalian; (2) Exochosphaeridium insigne Taxon-range Biozone (GOS2), lower through mid-Burdigalian; (3) Apteodinium spiridoides Interval Biozone (GOS3), mid-Burdigalian through lower Langhian; (4) Cleistosphaeridium placacanthum Interval Biozone (GOS4), upper Burdigalian, Langhian, and lower Serravallian?); and (5) Polysphaeridium zoharyi Assemblage Biozone (GOS5), upper Langhian and Serravallian? Comparison with other Miocene biozonations from the Mediterranean, Central Paratethys, North Atlantic region, and eastern USA indicate that the highest occurrences of Apteodinium spiridoides, Cordosphaeridium cantharellus, Distatodinium paradoxum, Exochosphaeridium insigne and Cleistosphaeridium placacanthum, and the lowest occurrences of Exochosphaeridium insigne and Sumatradinium soucouyantiae are important datums, whereas the lowest occurrences of Hystrichosphaeropsis obscura, Labyrinthodinium truncatum, and Operculodinium? borgerholtense provide useful supporting age control.

Environmental changes and diversification ofCyprideis in the Late Miocene of the Styrian Basin (Lake Pannon, Austria)

The turnover from the Sarmatian Paratethys Sea into Lake Pannon around 11.6 Ma seriously impacted aquatic biota like ostracods and triggered their adaptation to the changed environments. One survivor of this ecological switch is certainly the genusCyprideis, which is well known for its radiation in Lake Pannon. A high-resolution micropalaeontological investigation of a transgressive-regressive sedimentary cycle just above the Middle/Late Miocene boundary focused on the taxonomy of the foundCyprideis species. Species-diagnostic characters were evaluated applying qualitative as well as lineal and geometric morphometric analyses. These examinations led to the introduction of two new ostracod species (Cyprideis kapfensteinensisGross n. sp. andCyprideis mataschensisGross n. sp.), which diverge only indistinctly in outline, but are undoubtedly separated by their size and hinge structure along with considerable differences in number of posteroventral spines. We conclude that these co-occurring species were two sympatric species, which were probably adapted to different microhabitats.C. kapfensteinensis is only recognised in the interval at the peak of the transgression, which corresponds to the maximum deepening of the lake in this area and with meso-/polyhaline conditions. In contrast,C. mataschensis seems to be a more euryplastic species because it appears well before this event and is also recorded in the regressive prodelta sediments up section.

Upwelling conditions in the Early Miocene Central Paratethys Sea

Upwelling conditions in the Early Miocene Central Paratethys Sea Evidence for regional upwelling conditions in the Central Paratethys Sea is presented for mid-Burdigalian (early Ottnangian) times. The oceanographic phenomenon is detected in clay-diatomite successions along the steep escarpment of the Bohemian Massif in the eastern North Alpine Foreland Basin. Interpretations are based on a multiproxy data-set including published sedimentological and paleontological data, newly performed stable isotope measurements (δ18O, δ13C) of foraminifers and bulk sediment samples, and analyses of dinoflagellate cyst assemblages. The revealed stable isotope values of planktonic foraminifers point to upwelling: low δ13C values indicate strong mixing of surface waters with rising nutrient-rich waters, high δ18O values reflect cool sea surface temperatures (SST). Temperature calculations give SSTs ranging from 10-14 °C. Cool SSTs and high productivity are additionally supported by bulk sediment analyses. Assemblages of dinoflagellate cysts indicate a distal-shelf environment with nutrient-rich waters. Westerly winds and tidal currents are discussed as potential driving forces behind the local upwelling event. As mid-Burdigalian geography favoured strong current patterns in the Central Paratethys as documented in the sedimentary record from the Rhône Basin to Hungary upwelling might have been a more common phenomenon in this epicontinental sea than currently known.