The Mesozoic rise of the European freshwater gastropod fauna is still poorly understood. Compared to the well documented Cenozoic history, little is known about the patterns and processes underlying ...the early diversification preceding their extinction crisis at the K-Pg boundary. We assess what is probably a first pulse of diversification of the Cenozoic-type fauna in the Late Cretaceous along with the potential abiotic and biotic controls for shifts in species diversification. We find strong support that the increase in the speciation rate in the Santonian (~ 85 Myr ago) is linked to a global sea level rise, which caused extensive flooding of continental areas and the formation of vast brackish-water ecosystems. The following decline of the speciation rate coincides with a rise in diversity and reflects increasing interspecific competition. The peak in the speciation rate postdates the Cenomanian-Turonian Thermal Maximum, which probably limited the potential for diversification among freshwater gastropods due to ecological constraints. The peak coincides moreover with the end phase of the Cretaceous Terrestrial Revolution, which sparked the radiation of angiosperms. The expansion and diversification of flowering plants, being an important food source for freshwater gastropods today, could have formed a necessary basis for gastropod diversification.
Bryozoan–serpulid–algal–thrombolite bioherms of up to 50 cm size are described from the Sarmatian (upper Middle Miocene) of the Central Paratethys. They occur on top of lower Sarmatian carbonate ...sediments of high-energy conditions and the individual bioherms settle on crests of ripples. The buildups are overlain and partly truncated by cross-bedded oolites of late Sarmatian age. Buildup growth starts with a
Cryptosula/Hydroides
(bryozoan/serpulid) pioneer community, followed by nodular
Schizoporella
(bryozoan) colonies overgrown by coralline algae/microbial mats and a thrombolite with calcareous algal filaments. All these constituents form a framestone fabric which is overall dominated by bryozoans labeling them as bryoherms. Inside the bioherms ecological successions of higher frequencies occur which are interpreted to reflect short-time environmental fluctuations such as nutrient availability, oxygenation (possible anoxia), salinity (possible brackish water), temperature and water level. The internal succession in individual bioherms is related to long-term environmental changes including general shallowing, increasing nutrient supply and decreasing water circulation and oxygenation. The described bioherms are most similar to modern bryostromatolites of the Coorong lagoon in S Australia and also similar to structures in the Netherlands. The widespread occurrence of bryoherms/bryostromatolites in the Central Paratethys suggests a phase of considerable eutrophication during the early Sarmatian.
The origin and key details of the making of the ~ 30,000 year old Venus from Willendorf remained a secret since its discovery for more than a hundred years. Based on new micro-computed tomography ...scans with a resolution of 11.5 µm, our analyses can explain the origin as well as the choice of material and particular surface features. It allowed the identification of internal structure properties and a chronological assignment of the Venus oolite to the Mesozoic. Sampling numerous oolite occurrences ranging ~ 2500 km from France to the Ukraine, we found a strikingly close match for grain size distribution near Lake Garda in the Southern Alps (Italy). This might indicate considerable mobility of Gravettian people and long-time transport of artefacts from South to North by modern human groups before the Last Glacial Maximum.
Abstract The Miocene Climate Optimum (MCO, ~ 17–14 Ma) was a time of extraordinary marine biodiversity in the Circum-Mediterranean Region. This boom is best recorded in the deposits of the vanished ...Central Paratethys Sea, which covered large parts of central to southeastern Europe. This sea harbored an extraordinary tropical to subtropical biotic diversity. Here, we present a georeferenced dataset of 859 gastropod species and discuss geodynamics and climate as the main drivers to explain the changes in diversity. The tectonic reorganization around the Early/Middle Miocene boundary resulted in the formation of an archipelago-like landscape and favorable conditions of the MCO allowed the establishment of coral reefs. Both factors increased habitat heterogeneity, which boosted species richness. The subsequent cooling during the Middle Miocene Climate Transition (~ 14–13 Ma) caused a drastic decline in biodiversity of about 67%. Among the most severely hit groups were corallivorous gastropods, reflecting the loss of coral reefs. Deep-water faunas experienced a loss by 57% of the species due to changing patterns in circulation. The low sea level led to a biogeographic fragmentation reflected in higher turnover rates. The largest turnover occurred with the onset of the Sarmatian when bottom water dysoxia eradicated the deep-water fauna whilst surface waters-dwelling planktotrophic species underwent a crisis.
The Pannonian C hipparions from the Vienna Basin Bernor, Raymond L.; Göhlich, Ursula B.; Harzhauser, Mathias ...
Palaeogeography, palaeoclimatology, palaeoecology,
06/2017, Volume:
476
Journal Article
Peer reviewed
The “Hipparion” Datum has been recognized as being a key geochronologic marker for early late Miocene Eurasian and African horizons. The Vienna Basin Pannonian C hipparions are the stratigraphically ...oldest (basal MN9, ca. 11.4–11.0Ma), and we contend herein, the most primitive of all Old World hipparions. We evaluate the stratigraphic context, cheek tooth morphological characters, paleodietary and paleoenvironmental context of the three Pannonian C hipparion assemblages from Gaiselberg, Atzelsdorf and Mariathal, Austria. We find that the Gaiselberg and Atzelsdorf are slightly more primitive than the Mariathal hipparion assemblage and refer the first two assemblages to Hippotherium sp., while the Mariathal assemblage is referred to Hippotherium aff. primigenium exhibiting some advanced characters that presage Austrian and German later Vallesian age. We review the chronology and biogeography of the Old World “Hipparion” Datum and evolutionary relationships of first occurring European, West and South Asian and North African “Hipparion” to North American Cormohipparion. We evaluate, and expand upon earlier paleodietary studies of Pannonian C hipparions and determine that they were browser dominant, mixed “opportunistic” feeders.
•Vienna Basin Pannonian C hipparions are the oldest Old World Hipparions.•Cheek tooth morphology of Pannonian C hipparions is the most primitive.•Localities include Atzelsdorf, Gaiselberg and Mariathal.•Mesowear shows that Pannonian C hipparions were mixed feeders.
Continental aquatic species richness hotspots are unevenly distributed across the planet. In present-day Europe, only two centers of biodiversity exist (Lake Ohrid on the Balkans and the Caspian ...Sea). During the Neogene, a wide variety of hotspots developed in a series of long-lived lakes. The mechanisms underlying the presence of richness hotspots in different geological periods have not been properly examined thus far. Based on Miocene to Recent gastropod distributions, we show that the existence and evolution of such hotspots in inland-water systems are tightly linked to the geodynamic history of the European continent. Both past and present hotspots are related to the formation and persistence of long-lived lake systems in geological basins or to isolation of existing inland basins and embayments from themarine realm. The faunal evolution within hotspots highly depends on warm climates and surface area. During the Quaternary icehouse climate and extensive glaciations, limnic biodiversity sustained a severe decline across the continent and most former hotspots disappeared. The Recent gastropod distribution is mainly a geologically young pattern formed after the Last Glacial Maximum (19 ky) and subsequent formation of postglacial lakes. The major hotspots today are related to long-lived lakes in preglacially formed, permanently subsiding geological basins.
We present a detailed description of the Middle Miocene (Chokrakian and Karaganian) depositional environments of the Eastern Paratethys Sea in the southern Caspian Basin. The Chokrakian comprises a ...500-m-thick succession of marls and sandstones, termed herein Javarem Formation, which formed in coastal marine environments. The lower Javarem Fm. Developed in calm lagoonal settings, indicating frequent exposure under a predominantly dry climate and occasional formation of evaporites. The upper part of the Javarem Fm. Is characterized by mixed siliciclastic-carbonatic sediments with ooids of agitated, warm, hypersaline tidal shoals. Above follows the about 500-m-thick Vashi Formation, which is correlated with the Karaganian regional stage. The formation is characterized by an alternation of reddish marls with thick sandstones and gravel beds with terrestrial gastropods, ubiquitous pedogenetic features and occasional root horizons. The depositional environment is interpreted as a floodplain with gravelly channels of an arid to semiarid climate. The successions of the Javarem and Vashi formations capture the transition from the shallow marine Iranian shelf into the northern Iranian coastal plain around 13.8 Ma, following the onset of the Miocene Climate Transition and the coinciding global sea level drop around the Langhian/Serravallian boundary.
Graphical abstract
During the early and middle Miocene, the Dinarides Lake System (DLS) was a major hotspot of freshwater mollusk diversity in southeastern Europe. The numerous intramontane lake basins, originating by ...combined effects of tectonic subsidence and humid climate, accumulated thick lacustrine successions. Diagenetic overprint and leaching of these carbonate-rich deposits have facilitated insights to faunal contents for only a few basins up to the present. We contribute to filling this gap by documenting for the first time a mollusk fauna from the Bugojno Basin in Bosnia and Herzegovina. The fauna originates from a coal-bearing succession representing a gradual flooding of the coastal wetlands followed upwards by the establishment of perennial lacustrine settings in the basin. Our taxonomic analyses documents 17 gastropod and two bivalve species. New to science are
IIllyricocongeria forcakovici
nov. sp.,
Prososthenia krijgsmani
nov. sp. and
Bania goehlichae
nov. sp. The palaeoecological analysis based on quantified samples shows distinct shifts in mollusk composition and abundance. The terrestrial taxa are restricted to the coal-bearing interval of the section; melanopsids, neritids and hydrobiids are abundant in deltaic and littoral settings, whereas bivalves are frequent in littoral and sublittoral environments. In line with previous results, which have evidenced a high degree of intralacustrine radiation in the DLS, the Lake Bugojno fauna shows a low to moderate level of similarity to other DLS faunas. The dissimilarity may partly also result from its younger age as suggested by the presence or absence of regional biostratigraphic marker species.
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