Bicuspidon aff. hatzegiensis (Squamata: Scincomorpha: Teiidae) from the Upper Cretaceous Csehbánya Formation (Hungary, Bakony Mts)

Abstract

The recently discovered Upper Cretaceous (Santonian) Iharkút terrestrial vertebrate locality has yielded several vertebrate taxa since its discovery. Scincomorphan lizards are also represented in this fauna by several jaw fragments. The most abundant of these is represented by seven dentary fragments and an indeterminate jaw fragment with characteristic teeth. The hypertrophied splenial, the heterodont dentition, the cementum deposition at the bases of the teeth and the large subcircular resorption pits assign this type to the family Teiidae. The dentition composes of conical, monocuspid teeth in the mesial region and transversely widened bicuspid teeth in the distal region. This morphology is well known in members of the subfamily Polyglyphanodontinae. Based on their dental morphology the Iharkút finds can be easily assigned to the genus Bicuspidon. This genus is known from two species, B. numerosus East Europe). The Hungarian specimens differ from Bicuspidon numerosus while the latter has bicuspid teeth in the distal part of the tooth row, in contrast with the Hungarian species which has two monocuspid teeth in the distal region, one equal to the size of the preceding teeth, and one less than half the size of the former one. The presence of monocuspid teeth at the end of the tooth row resembles B. hatzegiensis, but while the very end of the tooth row of the latter is not known, it is not possible to determine if B. hatzegiensis also has two monocuspid teeth distally. Thus it is not impossible that the Hungarian specimens represent a new species but presently the lack of the needed information allows its determination only as Bicuspidon aff. hatzegiensis.

The first known chamopsiid lizard (Squamata) from the Upper Cretaceous of Europe (Csehbánya Formation; Hungary, Bakony Mts)

“…Other members of the family occur throughout the Late Cretaceous west of the Western Interior Seaway (Estes 1964(Estes , 1983Gao and Fox, 1996;Nydam et al, 2010). The occurrences of Bicuspidon (Makádi, 2006) and Pelsochamops at Iharkút support paleobiogeographic connections between North America and Europe before the Santonian, as suggested by other authors (Vullo and Néraudeau, 2008), morover these dispersal routes must have also crossed the Western Interior Seaway to let chamopsiids like Pelsochamops (and members of Polyglyphanodontinae such as Bicuspidon) disperse to landmasses in the European Archipelago.…”

“…Among these, the most abundant was Bicuspidon aff. hatzegiensis Folie and Codrea, 2005 from the subfamily Polyglyphanodontinae (Makádi, 2006), and even up till now Bicuspidon unambiguously remains the most frequent lizard of the locality. However, a partial lacertilian mandible with borioteiioid affinities was known to be present it the fauna already in 2006 and was mentioned as 'Teiidae indet.'…”

“…1), was discovered in 2000. Since that time, it has yielded remains of lepisosteid and pycnodontiform fishes (Ősi et al, 2012b), albanerpetontid and anuran amphibians Venczel, 2010, 2012;Szentesi et al, 2013), bothremydid turtles (Rabi et al, 2012), the first known freshwater mosasaur Pannoniasaurus (Makádi et al, 2012), alligatoroid, ziphosuchian and heterodont eusuchian crocodiles (Ősi et al, 2007; Ősi et al, 2012b), azhdarchid pterosaurs (Ősi et al, 2005), a rhabdodontid ornithopod (Ősi et al, 2012a), the ceratopsian dinosaur Ajkaceratops (Ősi et al, 2010b), the basal nodosaurid ankylosaur Hungarosaurus (Ősi, 2005;Ősi and Makádi, 2009), theropods (Ősi et al, 2010a), and enantiornithine birds (Dyke and Ősi, 2010) as well as well-preserved remains of lizards (Makádi, 2006(Makádi, , 2007Ősi et al, 2012b).…”

“…Previously four different lizards (excluding Pannoniasaurus) were distinguished in the Iharkút fauna, based on dentaries, maxillae and isolated teeth (Makádi, 2006(Makádi, , 2007Ősi et al, 2012b). Among these, the most abundant was Bicuspidon aff.…”

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

“…2). The robust teeth are subpleurodont with cementum deposition at their bases at an extent similar to Bicuspidon (Nydam and Cifelli, 2002;Folie and Codrea, 2005;Makádi, 2006). Similarly to Bicuspidon, the maxilla and the dentaries also differ from e.g.…”