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Przegląd
Geologiczny 48, 226-235. Summary.
A new Paleorhinus fauna has been discovered in a grey claystone
corresponding to the subsurface Drawno beds, which are exposed in a cement
plant claypit at Krasiejów near Opole in southern Poland. The vertebrate
assemblage of perfectly preserved skeletons, isolated skulls, and postcranial
remains is dominated with labirynthodonts Metoposaurus diagnosticus,
the phytosaur Paleorhinus sp. being the second in number. Aetosaurs
are represented by an incomplete skull, scuta and fragmentary bones. One
sacral bone most probably representing an early dinosaur related to Staurikosaurus
or Chindesaurus and two incomplete maxilla with teeth showing
serration parallel to the cusp have also been found. The Krasiejów assemblage
includes also dipnoans Ceratodus, undetermined fish scales and teeth,
numerous unionid bivalves, very abundant characean gyrogonites, and ostracods.
The Paleorhinus
species is relatively short-snouted and may represent an earlier stage in the
evolution of the lineage than the populations from Blasensandstein in
Franconia and other known Paleorhinus faunas. This is consistent with
the presence of Metoposaurus diagnosticus, the species originally
described from the Schilfsandstein, located below the Blasensandstein. An
equivalent of Schilfsandstein is known in boreholes drilled nearby the
locality and the bone-bearing horizon is about 80 m above its top, and about
20 m above the last occurrence of gypsum in the section. Lehrberg Schichten in
Germany seem thus to be its lateral equivalents, both presumably representing
the final event in the middle to late Carnian eustatic cycle. The Paleorhinus
fauna was apparently persistent in the area, as an incomplete skeleton has
been found about 8 m below the most fossiliferous horizon, in a calcareous
intercalation within red clays comparable with the German Rote Wand. |