Fossil Record 19(1): 17-29, doi: 10.5194/fr-19-17-2016
The westernmost occurrence of Gnathorhiza in the Triassic, with a discussion of the stratigraphic and palaeogeographic distribution of the genus
expand article infoP. Skrzycki‡
‡ Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
© P. Skrzycki.
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Citation: Skrzycki P (2016) The westernmost occurrence of Gnathorhiza in the Triassic, with a discussion of the stratigraphic and palaeogeographic distribution of the genus. Fossil Record 19(1): 17-29. https://doi.org/10.5194/fr-19-17-2016
Open Access
Abstract
The paper refines the taxonomic assignment of the only representative of thedipnoan genus Gnathorhiza from the Lower Triassic of Poland. It is assigned here toGnathorhiza otschevi on the basis of morphological and biometrical similarity with the toothplates from coeval strata of the European part of Russia. The material iscomprised solely of tooth plates, both the upper and the lower ones. Itcomes from karst deposits of the Czatkowice 1 locality (southern Poland)dated to late Olenekian, Lower Triassic. The presence of G. otschevi in southern Polandwidens its palaeobiogeographic Triassic record by more than 2000 km to thewest. Czatkowice 1 locality is the only known occurrence of gnathorhizidswithin the Germanic Basin. G. otschevi from Czatkowice 1 shows petrodentine in thetooth plate. Its presence is proved for the first time in a Triassicgnathorhizid. Gnathorhiza was most widely distributed during the Permian and restrictedto Europe in the Triassic. Tooth plates of both Early Triassic European andLate Permian Brazilian gnathorhizids are more similar to each other than toPermo-Carboniferous American ones.