scholarly journals Late miocene ostracodes of Serbia: Morphologic and palaeoenvironmental considerations

2006 ◽  
pp. 89-100 ◽  
Author(s):  
Ljupko Rundic

About 11.5 million years ago, a tectonic uplift of the Eastern and Western Carpathians separated the Pannonian Basin from the rest of the Paratethys. This orogenesis event caused an unconformity between the Sarmatian brackish sediments and the Pannonian lake-sea deposits. More than 6 Ma later, in these parts of the Paratethys, changes in the geographic framework, hydrological conditions and brackish - caspibrackish water chemistry led to the disappearance of restricted marine forms of life. A few euryhaline and marginal marine species survived this environmental change. Among the ostracodes, some originally freshwater taxa, such as Candoninae, entered the lake-sea. Many lineages show gradual morphological changes. The older, low diversity ostracode fauna from the Lower Pannonian dispersed to the endemic species and genera during the Upper Pannonian. This interval is assigned as the "bloom time" for many ostracodes, both qualitatively and quantitatively. This time sequence is the last appearances of genera such as Aurila Cytheridea, Propontoniella, etc. and simultaneously, the first appearances for many new genera, such as Zalanyiella, Serbiella, Camptocypria Sinegubiella etc. During the Pontian, migration processes were present. Therefore, it can be supposed that many eastern Paratethyan forms have Pannonian origin.

Paleobiology ◽  
2002 ◽  
Vol 28 (sp3) ◽  
pp. 1-71 ◽  
Author(s):  
John C. Barry ◽  
Michèle E. Morgan ◽  
Lawrence J. Flynn ◽  
David Pilbeam ◽  
Anna K. Behrensmeyer ◽  
...  

2018 ◽  
Vol 6 (1) ◽  
pp. SB111-SB122 ◽  
Author(s):  
Ferenc Horváth ◽  
Ivan Dulić ◽  
Alan Vranković ◽  
Balázs Koroknai ◽  
Tamás Tóth ◽  
...  

The Pannonian Basin is an intraorogenic extensional region floored by a complex system of Alpine orogenic terranes and oceanic suture zones. Its formation dates back to the beginning of the Miocene, and initial fluvial-lacustrine deposits pass into shallow to open marine strata, including a large amount of calc-alkaline volcanic materials erupted during the culmination of the synrift phase. The onset of the postrift phase occurred during the Late Miocene, when the basin became isolated and a large Pannonian lake developed. Early lacustrine marls are overlain by turbiditic sandstones and silts related to a progradational shelf slope and a delta plain sequence passing upward into alluvial plain deposits and eolian sands. A remarkable nonconformity at the top of lacustrine strata associated with a significant (4–7 my) time gap at large parts of the basin documents a neotectonic phase of activity, manifested by regional strike-slip faulting and kilometer-scale differential vertical movements, with erosion and redeposition. Subsidence and burial history modeling indicate that Middle and Late Miocene, fairly organic-rich marine and lacustrine (respectively) shales entered into the oil-generation window at about the beginning of the Pliocene in depocenters deeper than 2.5–3 km, and even reached the wet to dry gas-generation zone at depths exceeding 4–4.5 km. Migration out of these kitchens has been going on since the latest Miocene toward basement highs, where anticlines and flower structures offered adequate trapping conditions for hydrocarbons. We argue that compaction of thick sedimentary piles, in addition to neotectonic structures, has also been important in trap formation within the Pannonian Basin.


Author(s):  
G. Pogacsas ◽  
B. Bardocz ◽  
A. Szabo ◽  
E. Rosta ◽  
R. Mattick ◽  
...  

2019 ◽  
Vol 374 (1768) ◽  
pp. 20180186 ◽  
Author(s):  
Jennifer M. Donelson ◽  
Jennifer M. Sunday ◽  
Will F. Figueira ◽  
Juan Diego Gaitán-Espitia ◽  
Alistair J. Hobday ◽  
...  

Climate change is leading to shifts in species geographical distributions, but populations are also probably adapting to environmental change at different rates across their range. Owing to a lack of natural and empirical data on the influence of phenotypic adaptation on range shifts of marine species, we provide a general conceptual model for understanding population responses to climate change that incorporates plasticity and adaptation to environmental change in marine ecosystems. We use this conceptual model to help inform where within the geographical range each mechanism will probably operate most strongly and explore the supporting evidence in species. We then expand the discussion from a single-species perspective to community-level responses and use the conceptual model to visualize and guide research into the important yet poorly understood processes of plasticity and adaptation.This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.


2020 ◽  
Vol 98 (6) ◽  
pp. 377-389
Author(s):  
S. Naretto ◽  
M. Chiaraviglio

The intensity of mating competition varies according to the temporal and spatial distribution of individuals. Measuring sexual dimorphism over time and interpreting the association between individuals is therefore important if we aim to understand how sexual traits are influenced. We examined sex differences in the Achala Copper Lizard (Pristidactylus achalensis (Gallardo, 1964)), an endemic species from the highest part of mountains of central Argentina. Over 4 years, we explored sex-specific variation in body size, head size, interlimb length, and body colouration. Furthermore, we evaluated how these traits varied temporally, and we also explored whether the spatial distribution of individuals is explained by variation in these traits. We found that P. achalensis is a species with sexual dimorphism in multiple characters, including body size, head size, and colouration. Interestingly, some traits related to mating, such as head width, show a temporal variability in both sexes, whereas other traits, such as colouration, varies seasonally only in males. Our results underline the intriguing possibility of seasonal morphological changes related to mating, and more broadly that sex differences are influenced by sexual selection pressures mediated by temporal variation in mate competition.


2005 ◽  
Vol 42 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Douglas G Barton ◽  
Mark VH Wilson

The Eocene Horsefly locality in British Columbia has yielded many fossil fishes, insects, and plants. Its varved sediments make it ideal for study of temporal changes in environment and fish morphology. Several intervals of diatomaceous varves indicate a deep, stratified lake setting. Earlier studies focused on morphological and taphonomic change during the 700-year H2 interval and morphological change during the 10 000-year H3 interval. The present study uses taphonomy as an index for environmental change during the ten millennia represented by H3, comparing taphonomic changes with the morphologic changes found earlier. The H3 interval records deposition in deep water, indicated by dominance of the fish genera Amyzon and Eohiodon. Quiet water conditions are indicated by minimal fin disarticulation. Hypoxia at the time of fish death is confirmed by open mouths of most fish specimens, while cool water on the lake floor prevented full flotation of fish carcasses. Water depth, temperature, and oxygenation fluctuated during H3 deposition. Periods of cooler, deeper, more hypoxic water are indicated by greater numbers and size of Amyzon specimens and by less disarticulation of skull and abdominal bones. Periods of warmer, shallower, more oxygenated waters are indicated by more disarticulation, less fin tetany, smaller fish specimens, and greater diversity of species. Correlations between the taphonomic changes and morphological changes in A. aggregatum are weak. Therefore, the morphological changes are not easily explained as ecophenotypic or short-term evolutionary responses to changes in physical lake conditions.


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