The vertebrates from the Lower Ladinian (Middle Triassic)bonebed of Lamerden (Germany) as palaeoenvironmentindicators in the Germanic Basin

Abstract

A 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 ve di erent shark, and several actinopterygian sh 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 di erent 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 re ect a limnic/ uvial freshwater in uenced fauna (amphibians/terrestrial and marine reptiles) with dominance of normal saline marine in uences. Macroalgae meadow adapted placodont reptiles are absent in Lamerden, as well as open marine-adapted ichthyosaurs, supporting a lagoon with fresh water in uence 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.

A new Middle Triassic vertebrate assemblage from Miedary (southern Poland)

“…Remarks —Several disc-shaped, amphicoelous vertebral centra, very similar to ZPAL V. 36/517 and ZPAL V. 36/518, have been described from the Ladinian sediments of Germany (Diedrich, 2015; Fraas, 1896; Huene, 1951; Müller, 2002). These specimens were assigned to Blezingeria , an enigmatic marine reptile known only from isolated records (Müller, 2002).…”

Diversity of vertebrate remains from the Lower Gogolin Beds (Anisian) of southern Poland

“…As teeth lack any diagnostic features, their assignment to a specific taxon is uncertain. However, similar teeth were described as possibly belonging to Perleidiformes fish, often assigned to "Colobodus" tooth type (e.g., Diedrich, 2009Diedrich, , 2015Brachaniec et al, 2015;Nordén et al, 2015).…”

“…In lateral and ventral views, numerous foramina are present. The tooth-plate belonged to a durophagous fish, probably 'Colobodus' (e.g., Diedrich, 2009Diedrich, , 2015Nordén et al, 2015).…”