scholarly journals Oysters and oyster-like bivalves from the Middle Triassic Muschelkalk of the Germanic Basin

PalZ ◽  
2012 ◽  
Vol 87 (1) ◽  
pp. 19-32 ◽  
Author(s):  
M. Hautmann ◽  
H. Hagdorn
Keyword(s):  
Middle Triassic ◽  
Germanic Basin

scholarly journals Late Anisian microbe-metazoan build-ups ('stromatolites') in the Germanic Basin — aftermath of the Permian — Triassic Crisis

2021 ◽  
Author(s):  
Yu Pei ◽  
Jan-peter Duda ◽  
Jan Schoenig ◽  
Cui Luo ◽  
Joachim Reitner
Keyword(s):  
Microbial Mats ◽  
Middle Triassic ◽  
Ecological Niches ◽  
Carbon And Oxygen Isotopes ◽  
Germanic Basin ◽  
Sulfate Reducing ◽  
Mutualistic Relationship ◽  
Relative Rarity ◽  
Geochemical Analyses ◽  
Reducing Bacteria

The so-called Permian — Triassic mass extinction was followed by a prolonged period of ecological recovery that lasted until the Middle Triassic. Triassic stromatolites from the Germanic Basin seem to be an important part of the puzzle, but have barely been investigated so far. Here we analyzed late Anisian (upper Middle Muschelkalk) stromatolites from across the Germanic Basin by combining petrographic approaches (optical microscopy, micro X-ray fluorescence, Raman imaging) and geochemical analyses (sedimentary hydrocarbons, stable carbon and oxygen isotopes). Paleontological and sedimentological evidence, such as Placunopsis bivalves, intraclasts and disrupted laminated fabrics, indicate that the stromatolites formed in subtidal, shallow marine settings. This interpretation is consistent with δ13Ccarb of about -2.1 % to -0.4 %. Occurrences of calcite pseudomorphs after gypsum suggest slightly evaporitic environments, which is well in line with the relative rarity of fossils in the host strata. Remarkably, the stromatolites are composed of microbes (perhaps cyanobacteria and sulfate reducing bacteria) and metazoans such as non-spicular demosponges, Placunopsis bivalves, and/or Spirobis-like worm tubes. Therefore, these ″stromatolites″ should more correctly be referred to as microbe-metazoan build-ups. They are characterized by diverse lamination types, including planar, wavy, domal and conical ones. Microbial mats likely played an important role in forming the planar and wavy laminations. Domal and conical laminations commonly show clotted to peloidal features and mesh-like fabrics, attributed to fossilized non-spicular demosponges. Our observations not only point up that non-spicular demosponges are easily overlooked and might be mistakenly interpreted as stromatolites, but also demonstrate that microbe-metazoan build-ups were widespread in the Germanic Basin during Early to Middle Triassic times. In the light of our findings, it appears plausible that the involved organisms benefited from elevated salinities. Another (not necessarily contradictory) possibility is that the mutualistic relationship between microbes and non-spicular demosponges enabled these organisms to fill ecological niches cleared by the Permian — Triassic Crisis. If that is to be the case, it means that such microbe-metazoan associations maintained their advantage until the Middle Triassic.

Middle Triassic conodont assemblages from the Germanic Basin: implications for multi-element taxonomy and biogeography

2018 ◽  
Vol 17 (5) ◽  
pp. 359-377 ◽  
Author(s):  
Yanlong Chen ◽  
Frank Scholze ◽  
Sylvain Richoz ◽  
Zhifei Zhang
Keyword(s):  
Middle Triassic ◽  
Germanic Basin

The Middle Triassic marine reptile biodiversity in the Germanic Basin, in the centre of the Pangaean world

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Cajus Diedrich
Keyword(s):  
Middle Triassic ◽  
Coastal Areas ◽  
Skeletal Remains ◽  
Southern Germany ◽  
Shallow Marine ◽  
Germanic Basin ◽  
Marine Reptiles ◽  
Marine Habitats ◽  
Reptile Species ◽  
Marine Reptile

AbstractThe Middle Triassic fossil reptile localities near Bayreuth (Bavaria, southern Germany) consist of shallow marine autochthonous glauconitic marls and terebratulid-rich tempestite carbonates of the newly defined Bindlach and Hegnabrunn formations. Single bones and incomplete skeletons of marine reptiles have been recorded in bone beds within in the Illyrian and Fassanian stages. These include the remains of the sauropterygians Neusticosaurus sp., Lariosaurus cf. buzzii [1], Nothosaurus mirabilis [2], Paranothosaurus giganteus [2], Placodus gigas [3], Cyamodus rostratus [4], Cyamodus münsteri [5], Pistosaurus longaevus [6], and ichthyosaursOmphalosaurus sp., and Shastasaurus sp. or proterosaur Tanystrophaeus conspicuus [7]. New skeletal reconstructions are based on the osteological analysis of three dimensionally preserved bones and skeletal remains. The large number of marine endemic placodont macroalgae feeders (P. gigas) in the Bayreuth sites coincides with the presence of invertebrate palaeocommunities that are characteristic of macroalgae meadow paleoenvironments. Most of the reptile species and genera from the Bayreuth localities also occur in beds of similar ages from the Monte San Giorgio (Switzerland/Italy) or Perledo (Italy) lagoonal areas. Ichthyosaurs and pistosaurs were adapted for open marine conditions, and may have migrated from the Panthalassa Oceans into the shallow marine Germanic Basin to reproduce, whereas placodonts and many other sauropterygians seem to have lived permanently in those shallow marine habitats, with large squamates and thecodont or smaller archosaurs in coastal areas.

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