Placodont remains (Sauropsida, Sauropterygia) from the Triassic of Hungary (Transdanubian Range and Vill\xe1ny Mountains)

Kinga Gere,Torsten M Scheyer,Attila Ősi,László Makádi

doi:10.1007/s12549-020-00432-5

Abstract

New placodont remains from the Triassic of Hungary are described here. They come from two different tectonic units: the Transdanubian Range Unit representing Alpine type sedimentary basins and the Villány-Bihar Unit that was part of the southern passive margin of the European Plate during the Triassic. The fossils came from four stratigraphic levels with the oldest specimen, a maxilla fragment found in the upper Anisian of Forrás Hill, near Felsőörs (Transdanubian Range). Based on dental morphology, the specimen is referred to here as Paraplacodus broilii. This site is similar in age to the Monte San Giorgio (Switzerland and Italy) locality. A Carnian occurrence of placodonts from this tectonical unit is a dentary fragment and two isolated teeth referred to here as Placochelys placodonta. The youngest specimen from this unit is a placochelyid tooth fragment from the Rhaetian of the Keszthely Mountains (Transdanubian Range). The richest assemblage of new placodont remains is from the Ladinian of the Villány Mountains, southern Hungary. Cranial elements are referred to here as Cyamodus sp. Teeth from this site are similar to that of Cyamodus sp. described from Slovenia, and both assemblages are among the last occurrences of the genus in the European Triassic. The Villány site is considered as a gap locality because of the rarity of Ladinian placodont occurrences in the German-Alpine sedimentary basins.

Highlights

Bones and teeth of placodont reptiles are relatively frequent fossils of Middle to Late Triassic marine vertebrate sites, and this is the case in the Carpathian region
The Alpine-type Transdanubian Range Unit contains the oldest Hungarian placodont, Paraplacodus broilii from Felsőörs (Balaton Highland)
This specimen is similar in age to the occurrences of the species in Monte San Giorgio (Switzerland) and Besano Formation (Italy); these sites had similar palaeogeographical position in the Anisian in the Tethyan realm

Summary

Introduction

Bones and teeth of placodont reptiles are relatively frequent fossils of Middle to Late Triassic marine vertebrate sites, and this is the case in the Carpathian region. Laczkó in the Upper Triassic of Jeruzsálem Hill on the outskirts of the town of Veszprém (Bakony Mountains, Transdanubian Range) in 1899. That year has been traditionally accepted as the date of finding a partial skeleton (later described as the Palaeobio Palaeoenv (2020) 100:1047–1063 incompletely prepared holotype skull and mandible, which was later studied and redescribed, among others, by Huene (1931) and Rieppel (2001) in its fully prepared condition. Detailed studies followed on the dermal armour (Jaekel 1902b, 1907; Kormos 1917; Rieppel 2002a) and on the reconstruction of the musculature (Rieppel 2002b). Some specimens collected from the same beds were never published

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