A new polyglyphanodontine lizard (Squamata: Borioteiioidea) from the Late Cretaceous Iharkút locality (Santonian, Hungary)

Abstract

In recent years the Late Cretaceous (Santonian) terrestrial vertebrate locality at Iharkút (western Hungary) has yielded well-preserved remains of lizard taxa besides the remains of fishes, amphibians, turtles, crocodiles, pterosaurs and dinosaurs. Previously the polyglyphanodontine lizard Bicuspidon aff. hatzegiensis has been reported from Iharkút. However, recent excavations at this site produced more lacertilian remains including new polyglyphanodontine material, namely a maxilla and two dentaries which suggest the presence of a new genus in the Iharkút fauna. This previously unknown lizard (described here as Distortodon rhomboideus n. g. n. sp.) is distinct from other polyglyphanodontines such as Bicuspidon, Paraglyphanodon, Polyglyphanodon, Dicothodon and Peneteius. It differs from these genera mainly in having the lingual cusp situated more distally compared to the labial one on its bicuspid teeth located in the distal part of the tooth row, thus the crowns having a unique rhomboidal shape in occlusal view. Distortodon rhomboideus further strengthens the dominance of borioteiioid lizards in the Iharkút fauna. The growing presence of borioteiioids in European localities supports previous theories which suggest some paleobiogeographic connections between the western Tethyan archipelago and North America in the Late Cretaceous. Research highlightsNew lizard remains have been found in the Late Cretaceous of Hungary. The remains show features typical of polyglyphanodontines. Based on some differences between these specimens and previously described genera a new genus and species is described.

Collection of the thinnest: A unique eggshell assemblage from the Late Cretaceous vertebrate locality of Iharkút (Hungary)

“…The other four lizard taxa recovered from Iharkút, Bicuspidon aff. hatzegiensis, Pelsochamops infrequens, Distortodon rhomboideus, and Chromatogenys tiliquoides (Makádi 2006(Makádi , 2013a(Makádi , 2013bMakádi and Nydam 2015), and the other, yet undescribed scincomorphs (Makádi pers. comm.…”

“…MT IV is most likely attributable to the rigid eggs of a squamate; a group of sauropsids exhibiting moderate diversity in the locality being represented by skeletal remains of four determinable and four indeterminate taxa of small-bodied terrestrial lizards and the freshwater mosasaur Pannoniasaurus inexpectatus (Makádi 2006(Makádi , 2013a(Makádi , 2013bMakádi et al 2012). As even basal mosasaurs were shown to have been live-bearing (Caldwell and Lee 2001;Field et al 2015), and because of the extreme thinness and hence inferred small egg size of MT IV, the hypothesis that MT IV belonged to Pannoniasaurus can be discarded.…”

Morphometry, Microstructure, and Wear Pattern of Neornithischian Dinosaur Teeth From the Upper Cretaceous Iharkút Locality (Hungary)

“…Most of the dental material studied here (63 teeth with and 94 without a primary ridge) was collected from the Upper Cretaceous (Santonian) fluvial Csehbánya Formation during the productive and continuous excavations carried out in the last 15 years at Iharkút in the Bakony Mountains of western Hungary (see Ősi et al, ; Botfalvai et al, for geological settings). The site provided an exceptionally rich and diverse assemblage of continental vertebrates, including fish, amphibians, turtles, mosasaurs, lizards, pterosaurs, crocodilians, non‐avian dinosaurs and birds (see e.g., Ősi, ,b; Ősi et al, , 2010a,b, , 2012a,b; Makádi, , ; Ősi and Makádi, ; Ősi and Weishampel, ; Dyke and Ősi, ; Szentesi and Venczel, ; Ősi and Buffetaut, ; Rabi et al, ; Makádi et al, ; Ősi and Prondvai, ; Szentesi et al, ; Csiki‐Sava et al, ; Szabó et al, ), as well as plants (Knauer and Siegl‐Farkas, ; Bodor and Baranyi, ; Bodor et al, ). The specimens used here were previously referred to the genus Mochlodon , and are now stored in the Invertebrate and Vertebrate Paleontological Collection of the Hungarian Natural History Museum (MTM) in Budapest.…”

A new durophagous scincomorphan lizard genus from the Late Cretaceous Iharkút locality (Hungary, Bakony Mts)

“…The polyglyphanodontines Bicuspidon aff. hatzegiensis and Distortodon rhomboideus, and the chamopsiid Pelsochamops infrequens, all belong to groups described from North America, and differ from Chromatogenys (see below) (Makádi 2006(Makádi , 2013aMakádi et al 2012). Scincomorphs from the Maastrichtian of Transylvania are again Bicuspidon hatzegiensis, as well as the paramacellodids Becklesius nopcsai Folie and Codrea, 2005 and Becklesius cf.…”

“…14 There were only a few exceptions when these scincomorphs could be determined at genus or species level (Folie and Codrea 2005;Makádi 2006Makádi , 2013a. Material adequate for comparisons is available mainly at Iharkút and in Transylvania.…”