Chirotherium trackways and feeding traces on seismic-influenced carbonate intertidals of the Middle Triassic of Central Europe: global food chain reactions onto horseshoe crab reproduction mud flat beaches of the Germanic Basin

2015 ◽  
Vol 31 (2) ◽  
pp. 187-211 ◽  
Author(s):  
Cajus G. Diedrich
2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Cajus Diedrich

AbstractChirotherid footprints of Synaptichnium, Chirotherium and Isochirotherium appeared during the late Early (Aegean) to early Late (Carnian) Triassic in central Europe. These taxa are partly revised herein, using both perfect and variably preserved tracks, and very long trackways from an upper Pelsonian intertidal-flat megatracksite of the Germanic Basin coast Pelsonian (Karlstadt Formation). The global Middle Triassic distribution of those footprints suggests seasonal migrations across Pangaea of possible archosauriform reptile trackmakers, such as Euparkeria, Ticinosuchus, Arizonasaurus and Batrachotomus, caused by horseshoe-crab mass migrations into tidal-flat beach reproductive zones in the Germanic Basin. Such seasonal migrations may even suggest a Pangaea-wide food-chain reaction, possibly including the mobilization of fish, marine and terrestrial reptiles, and of which situation the Germanic Basin intertidal-flats is a globally unique example.


2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Cajus G. Diedrich

AbstractA marine/limnic vertebrate fauna is described from the enodis/posseckeri Bonebed mixed in a bivalve shell-rich bioclastic carbonate rudstone at the eastern coastal margin of the Rhenish Massif mainland at Lamerden (Germany) within the western Germanic Basin (Central Europe). The condensation layer is of Fassanian (Ladinian, Middle Triassic) in age. The vertebrate biodiversity includes five different shark, and several actinopterygian fish species represented by teeth and scales. Abundant isolated bones from a small- and a large-sized pachypleurosaur Neusticosaurus species, which can be composed as incomplete skeletons, originate from dense populations of different individual age stages. Important facies indicator reptiles are from the thalattosaur Blezingeria ichthyospondyla which postcranial skeleton is reconstructed hypothetically using additional postcranial bones from similar aged various German localities. The vertebrate biodiversity of the enodis/posseckeri bonebed of Lamerden reflect a limnic/fluvial freshwater influenced fauna (amphibians/terrestrial and marine reptiles) with dominance of normal saline marine influences. Macroalgae meadow adapted placodont reptiles are absent in Lamerden, as well as open marine-adapted ichthyosaurs, supporting a lagoon with fresh water influence position at the Rhenish Massif mainland coast. In those contemporanous brackish lagoons, which seem to be isochronous to northern Tethys lagoons of the Kalschieferzone at the Monte San Giorgio (Switzerland/Italy), small pachypleurosaurs were abundant prey in both regions for reptile predators, especially large paraxial swimming alligator habitus-like Paranothosaurus, which even contain stomach contents of pachypleurosaurs.


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

2021 ◽  
Author(s):  
Yu Pei ◽  
Jan-peter Duda ◽  
Jan Schoenig ◽  
Cui Luo ◽  
Joachim Reitner

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.


2005 ◽  
Vol 42 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Andrew G Neuman ◽  
Raoul J Mutter

A new species of stem actinopterygian, Helmolepis cyphognatus sp. nov., is reported from the Lower Triassic Sulphur Mountain Formation of western Canada (probably Smithian). This taxon differs from the only other known Early Triassic platysiagid, H. gracilis from the Lower Triassic Wordie Creek Formation of East Greenland (Griesbachian), in counts of branchiostegal rays, shape of the maxilla, shape (and possibly counts) of extrascapulars, and the size ratio of major opercular bones. In spite of their overall unfavorable preservation, the numerous available specimens amend our knowledge of the little known genus Helmolepis considerably: it has become evident that the morphology of Helmolepis cyphognatus sp. nov. comes closest to Platysiagum minus (Middle Triassic Besano Formation of central Europe). This study suggests placement of the two genera in the family Platysiagidae. Investigation of this new species also shows certain features of the cheek and the caudal fin are more primitive than previously believed, whereas the snout region is probably derived but of yet uncertain affinities in Helmolepis.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Shixue Hu ◽  
Qiyue Zhang ◽  
Rodney M. Feldmann ◽  
Michael J. Benton ◽  
Carrie E. Schweitzer ◽  
...  

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