A new ornithopod dinosaur, Transylvanosaurus platycephalus gen. et sp. nov. (Dinosauria: Ornithischia), from the Upper Cretaceous of the Haţeg Basin, Romania

Rhabdodontid dinosaurs were a group of medium-sized iguanodontian ornithopods from the Late Cretaceous of Europe. The uppermost Cretaceous continental deposits from the Haţeg Basin of western Romania yielded a very rich assemblage of vertebrates including abundant rhabdodontid remains, which have been exclusively referred to the genus Zalmoxes thus far. Here we describe a new rhabdodontid dinosaur, Transylvanosaurus platycephalus gen. et sp. nov., from the uppermost Cretaceous of the Haţeg Basin. The holotype of the new taxon was discovered in early–late Maastrichtian strata near Pui in the eastern part of the basin and comprises the articulated basicranium and both frontals. Transylvanosaurus differs from all previously reported rhabdodontids in having particularly wide and crested frontals, elongated and straight paroccipital processes that make only a gentle lateral curve and project mostly posterolaterally, prominent and massive prootic processes that extend mainly anterolaterally and ventrally, wide and crest-like basal tubera that meet the long axis of the braincase at a very flat angle, widely splayed basipterygoid processes that extend mainly ventrolaterally and slightly anteriorly, as well as a well-developed notch on the lateral side of the basicranium that is continuous, straight, and inclined anteroventrally. Phylogenetic analyses employing two different datasets consistently recovered the new taxon within the Rhabdodontidae, at the base of the iguanodontian radiation. Based on the morphological comparisons presented herein, we propose a particularly close relationship between Transylvanosaurus and Rhabdodon from southern France, which in turn provides evidence for a more complex biogeographic history of the Rhabdodontidae than previously thought

A Sauropod Tooth from the Santonian of Hungary and the European Late Cretaceous 'Sauropod Hiatus'

The lack of sauropod body fossils from the 20 My-long mid-Cenomanian to the late Campanian interval of the Late Cretaceous in Europe is referred to as the 'sauropod hiatus', with only a few footprints reported from the Apulian microplate (i.e. the southern part of the European archipelago). Here we describe a single tooth from the Santonian continental beds of Iharkut, Hungary, that represents the first European body fossil evidence of a sauropod from this critical time interval. The mosaic of derived and plesiomorphic features documented by the tooth crown morphology points to a basal titanosauriform affinity suggesting the occurrence of a clade of sauropods in the Upper Cretaceous of Europe that is quite different from the previously known Campano-Maastrichtian titanosaurs. Along with the footprints coming from shallow marine sediments, this tooth further strengthens the view that the extreme rarity of sauropod remains from this period of Europe is the result of sampling bias related to the dominance of coastal over inland sediments, in the latter of which sauropod fossils usually occur. This is also in line with the hypothesis that sauropods preferred inland habitats to swampy environments

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

As a result of several years of screen-washing activity, a remarkable assemblage of eggshell fragments has been recovered from the Late Cretaceous vertebrate locality of Iharkút, Hungary. Detailed investigation of the assemblage by multiple visualization techniques (scanning electron microscopy, polarizing light microscopy, X-ray micro-computed tomography), quantitative morphometric analyses, and micro X-ray fluorescence spectrometry revealed a diverse composition of five different eggshell morphotypes (MT I-MT V) and three subcategories within the second morphotype (MT II/a, b, c), with MT I being by far the most abundant (83%) in the assemblage. MT I, MT III, and MT V represent theropod dinosaurian eggshells, whereas MT II and MT IV show characteristics of crocodilian and squamate eggshells, respectively. Hence, despite their fragmentary nature, these eggshells represent the first clear evidence that various sauropsid taxa had nesting sites near the ancient fluvial system of Iharkút. Besides the implied taxonomic diversity, two unique features add to the significance of this eggshell assemblage. First, it contains the thinnest rigid crocodilian (MT II/c) and squamate (MT IV) eggshells ever reported. Moreover, one of the identified theropod morphotypes, MT I, is also among the thinnest fossil dinosaurian eggshells, the thinness of which is only rivalled by the eggshells of the smallest Mesozoic avian eggs known to date. Second, the Iharkút eggshell assemblage consists exclusively of thin eggshells (≤300 μm), a condition unknown from any other fossil eggshell assemblages described to date. Combined with the knowledge acquired from skeletal remains, these peculiarities give additional insights into the paleoecology of the terrestrial sauropsid fauna once inhabiting the ancient island of Iharkút. Finally, the presence of well-preserved eggshells recovered from two different sites representing different depositional environments provides further evidence for previous taphonomic and sedimentological conclusions, and also expands our knowledge of the special conditions that allowed the preservation of these delicate eggshell fragments. © 2017 The Author(s)

Meeting Island Dwarfs and Giants of the Cretaceous – The Hațeg Country UNESCO Global Geopark, Romania

We review here key geological heritage elements of the Hațeg Country UNESCO Global Geopark (Southern Carpathians, western Romania) represented by latest Cretaceous continental vertebrate fossils and the sedimentary rocks enclosing them. Based on available geological and paleontological evidence, these animals were living on a tropical island. This paleogeographic setting led to the development of some unusual paleobiological traits including dwarfing of the dinosaurs, high levels of endemism, relictual characteristics, as well as uniquely derived anatomical, developmental, metabolic and/or sensory features. These unique characteristics led to the establishment of the Hațeg Country UNESCO Global Geopark over a decade ago. Recently, the Geopark implemented several projects including specific ‘Dinosaur Island’-related thematic trails and visits to key geoheritage elements. We focus on four key fossiliferous areas of the Geopark, highlighting the most important geoheritage elements of each, as well as the most significant geoproducts created based on these particular elements

New ankylosaurian material from the Upper Cretaceous of Transylvania | Nouveau matériel d’ankylosaure du Crétacé supérieur de Transylvanie

Ankylosaurian remains from the Transylvanian Basin, Romania, are extremely rare. More than 100 years after the discovery of the first and only better-known assemblage, namely the type material of Struthiosaurus transylvanicus, new ankylosaurian material has been discovered in the Maastrichtian of the Haţeg Basin, as well as at another locality (Vurpăr), in the Transylvanian Basin, that is described here. The material consists of one tooth in a small jaw fragment (from the Haţeg Basin) and at least two accummulations of associated, as well as several isolated, postcranial elements (from Vurpăr). No diagnostic elements are preserved that would overlap with the type of S. transylvanicus, so we cannot assign any of the new specimens to this species. The tooth shows marked differences compared to those of other anklyosaurs including S. austriacus and Hungarosaurus in having only six, more or less equally sized, apically pointed cusps separated by deep grooves. The postcranial material from Vurpăr represents at least three different individuals. The humerus is the most diagnostic element among the postcranial remains being most similar both in size and morphology to humeri referred to as Struthiosaurus from different European localities, thus here we refer the humerus and probably associated elements preserved in one assemblage to as cf. Struthiosaurus sp.; the remaining specimens from Vurpăr are retained as Nodosauridae indet. Histological studies have confirmed the adult nature of all sampled bones in the Vurpăr ankylosaur material suggesting that these fully grown animals were of similar size to Struthiosaurus, a small-bodied nodosaurid the ontogenetic status of which, however, has never been investigated histologically. The obviously diminished body size of the Transylvanian ankylosaurs compared to other members of the clade could be explained by insular dwarfism using the same histology-based argument as presented for Magyarosaurus. | Les restes fossiles d’ankylosaure provenant du Bassin de Transylvanie, en Roumanie, sont extrêmement rares. Plus d’un siècle après la première découverte, qui est également l’association la mieux préservée, à savoir le matériel-type de Struthiosaurus transylvanicus, le nouveau matériel ici décrit provient du Maastrichtien du Bassin de Haţeg et aussi d’une autre localité (Vurpăr) du Bassin de Transylvanie. Le matériel comprend un petit fragment de mâchoire avec une dent (du Bassin de Haţeg) et au moins deux accumulations d’éléments postcrâniens associés, mais aussi isolés (à Vurpar). Aucun élément diagnostique en concordance avec le type de S. transylvanicus n’étant conservé, il n’est pas possible de rapporter ces nouveaux spécimens à cette espèce. La dent présente des différences par rapport aux autres ankylosaures, y compris S. austriacus et Hungarosaurus, dans la mesure où elle présente seulement six denticules, de tailles plus ou moins égales, pointus apicalement et séparés par des sillons profonds. Le matériel postcrânien de Vurpăr appartient à au moins à trois individus différents. L’humérus étant l’élément le plus diagnostique parmi les restes postcrâniens ayant plus de similitudes dimensionnelles et morphologiques aves les humérus attribués à Struthiosaurus provenant de différentes localités européennes, il est par conséquent attribué, ainsi que probablement les autres éléments préservés dans l’une des associations, à cf. Struthiosaurus sp. ; les autres spécimens de Vurpăr sont rapportés à un Nodosauridae indet. Les études histologiques ont confirmé l’état adulte de tous les os d’ankylosaure échantillonnés de Vurpăr, suggérant que ces animaux matures étaient de taille comparable à Struthiosaurus, un nodosauridé de petite taille dont l’état ontogénétique n’a jamais été étudié d’un point de vue histologique. La taille manifestement réduite des ankylosaures de Transylvanie comparée à celle d’autres membres du clade pourrait être expliquée du fait d’un nanisme insulaire, si l’on prend en compte le même argument histologique que celui présenté pour Magyarosaurus

Cranial morphology of Theriosuchus sympiestodon (Mesoeucrocodylia, Atoposauridae) and the widespread occurrence of Theriosuchus in the Late Cretaceous of Europe

We present a detailed morphological description of the type-locality cranial material of Theriosuchus sympiestodon Martin, Rabi, and Csiki, 2010 from the Maastrichtian Densus-Ciula Formation of the Hatxeg Basin, Romania together with new material of isolated cranial elements and teeth from various sites of the same general area. The recognition of several individuals of distinct sizes allows for an assessment of ontogenetic variation in this taxon. New material, consisting of isolated teeth and an incomplete maxilla with in situ teeth, coming from various late Campanian/ early Maastrichtian sites in southern France is referable to ?Theriosuchus sp. and hints to a rare but widespread distribution of Theriosuchus in the Late Cretaceous European archipelago

Reappraisal of the braincase anatomy of the ornithopod dinosaurs Telmatosaurus and Zalmoxes from the Upper Cretaceous of the Haţeg Basin (Romania) and the taxonomic reassessment of some previously referred specimens

The hadrosauroid Telmatosaurus and the rhabdodontid Zalmoxes were the first and second dinosaur taxa that were described in detail from the famous Upper Cretaceous continental deposits of the Haţeg Basin by Franz Baron Nopcsa at the beginning of the twentieth century. Although they are among the most common and best-known dinosaurs discovered from these deposits, there are still many open questions as to their taxonomy and anatomy. Here, we re-describe two partial braincases from the uppermost Cretaceous of the Haţeg Basin that have been recently referred to the rhabdodontid Zalmoxes and re-assign them to hadrosauroids, possibly to Telmatosaurus. These specimens both exhibit basicranial features that are characteristic of derived hadrosauroids but are absent in more basal iguanodontians. These include an antero-posteriorly short basioccipital lacking a distinct neck, the presence of two well-developed sphenoccipital tubercles on the ventral aspect of the braincase and that are directly positioned anterior to the basioccipital, as well as a deep depression on the ventral aspect of the braincase between the sphenoccipital tubercles. The comparison provided herein demonstrates several important differences between the basicranium of hadrosauroids and that of rhabdodontids, which allows for the confident identification of even isolated and incomplete specimens. Moreover, the removal of the only basicranium that has been referred to Zalmoxes shqiperorum prompts a revised diagnosis of that species

Catalog of Zalmoxes fossils.

34 pages : illustrations (chiefly color), color map ; 26 cm.The Transylvanian area of Romania boasts a rich fossil record of dinosaurs, which lived on an island (Haţeg Island) during the very end of the Cretaceous. Many of these are dwarfed in body size or exhibit other unusual features thought to be linked to their insular habitat. One of the most common of these dinosaurs is the rhabdodontid ornithopod Zalmoxes, an herbivorous taxon that has been found at many Upper Cretaceous sites across Transylvania. Our collaborative fieldwork has uncovered several new Zalmoxes specimens from the Nălaț-Vad (= Vadu) locality, a site along the Râul Mare River in the Hațeg Basin that dates to the "middle" to late Maastrichtian. These include a partial associated skeleton, along with various isolated bones from several additional individuals. We catalog and describe these specimens here, and compare them to other Zalmoxes fossils from Romania. They provide further evidence that Zalmoxes was one of the most common vertebrates in the latest Cretaceous of Transylvania, and add to the unusual fossil record of Nălaț-Vad, which has yielded a much greater number of associated skeletons than other Transylvanian localities. Some of the Nălaț-Vad specimens possess features characteristic of the type species, Z. robustus, whereas others exhibit features diagnostic of the larger and stockier Z. shqiperorum, indicating that these species were locally sympatric, as has been demonstrated at other Transylvanian sites. The specimens span much of the size range known from Zalmoxes, as well as the spatial and temporal extent of the Nălaț-Vad locality, suggesting that this taxon flourished until near the end of the Cretaceous