Attila Ősi

Atoposauridae comprises a group of diminutive, semiterrestrial, brevirostrine neosuchian crocodyliforms that represents a characteristic component of European Jurassic–Cretaceous tetrapod faunas. Although frequently evaluated within the context of crown-group Crocodylia origins, their highly contested phylogenetic relationships continue to obscure their precise role in crocodylomorph evolutionary history. Particular ambiguity surrounds the monophyly of the genus Theriosuchus —with some hypotheses inferring long-term persistence of the lineage in Mesozoic Europe, whereas others interpreting select Cretaceous species as representatives of separate, even non-atoposaurid clades (e.g. Sabresuchus spp). We describe a new, stratigraphically intermediate taxon from the Santonian of Hungary based on isolated cranial elements, consistently placed as the sister taxon of Sabresuchus (Theriosuchus) sympiestodon from the Maastrichtian of Romania by our comprehensive set of phylogenetic analyses using three separate datasets. Sabresuchus tribodon sp. nov. is either recovered within Atoposauridae (global datasets) or Paralligatoridae (ingroup analysis) and can be distinguished from all other representatives of these groups by a specialized morphology consisting of massive, thick-enameled bulbous posterior maxillary teeth ornamented with apicobasal ridges, an extremely short rostrum with a reduced number of maxillary and dentary teeth, and the significantly upturned dorsal margin of the posterior dentary and surangular. Comparable anatomical adaptations are present in ecomorphologically convergent extinct crocodyliforms whose inferred feeding ecology included durophagy. However, this complete suite of characters has not been previously documented in either atoposaurids or paralligatorids. Our systematic reassessment results in an up-to-date taxonomy of Cretaceous European atoposaurids and tentatively confirms the polyphyly of Theriosuchus , though more definitive conclusions require combining individual, differently focused datasets. We reinterpret Aprosuchus ghirai from the Maastrichtian of Romania as a junior synonym of Sabresuchus sympiestodon and the putative European notosuchian Ogresuchus furatus from the Maastrichtian of Spain as an indeterminate atoposaurid.

Inferred biotic exchanges between Europe and Africa during the Cretaceous have been used to support the hypothesis that the complete separation of Europe from Gondwana postdated the split of the remaining Laurasian landmasses from Gondwana. Under this framework, Europe, conceptualized as part of a proposed ‘Eurogondwana’, is thought to have maintained biogeographic connections with Africa well into the Cretaceous. A key piece of evidence underpinning this hypothesis has been the crocodyliform Doratodon carcharidens from the Late Cretaceous of Europe, previously interpreted as closely related to Gondwanan taxa. However, the material attributed to this species is fragmentary, and its skeletal anatomy—critical for phylogenetic inference—remains poorly understood. Here we describe a new partial skull of Doratodon carcharidens which represents some of the most complete material of ‘Gondwanan’ taxa in the European Cretaceous. Our updated phylogenetic analysis unexpectedly and robustly places D. carcharidens among the Laurasian clade Paralligatoridae and reveals that morphological similarities to Gondwanan ziphosuchians, such as ziphodont dentition, are the result of remarkable ecomorphological convergence rather than shared ancestry. By reinterpreting the systematic position of further taxa representing biogeographic enigma, such as Ogresuchus furatus , our phylogeny implies a major role of the primary breakup of Pangea into Laurasia and Gondwana for crocodyliform divergence. A critical reassessment of the purported evidence for ‘Gondwanan’ fish and tetrapod immigrants in Europe reveals that it is largely based on highly fragmentary and sporadic specimens, as well as weakly supported phylogenetic hypotheses. Given the sparse and uneven Jurassic and Cretaceous fossil record in both Europe and Africa, it remains plausible that taxa previously interpreted as Gondwanan dispersers instead represent vicariant relicts. Our results conflict with recent paleobiogeographic scenarios, highlight the absence of compelling evidence for the Eurogondwana hypothesis and instead support a primary Gondwana-Laurasia split.

The first scientifically described dinosaur fossil from Transylvania is a quasi-completely preserved but crushed hadrosauroid skull (NHMUK R.3386), discovered by Ilona Nopcsa in 1895 along the Sibi...

Inferred biotic exchanges between Europe and Africa during the Cretaceous have been used to support the hypothesis that the complete separation of Europe from Gondwana postdated the split of the remaining Laurasian landmasses from Gondwana. Under this framework, Europe, conceptualized as part of a proposed ‘Eurogondwana’, is thought to have maintained biogeographic connections with Africa well into the Cretaceous. A key piece of evidence underpinning this hypothesis has been the crocodyliform Doratodon carcharidens from the Late Cretaceous of Europe, previously interpreted as closely related to Gondwanan taxa. However, the material attributed to this species is fragmentary, and its skeletal anatomy—critical for phylogenetic inference—remains poorly understood. Here we describe a new partial skull of Doratodon carcharidens which represents some of the most complete material of ‘Gondwanan’ taxa in the European Cretaceous. Our updated phylogenetic analysis unexpectedly and robustly places D. carcharidens among the Laurasian clade Paralligatoridae and reveals that morphological similarities to Gondwanan ziphosuchians, such as ziphodont dentition, are the result of ecomorphological convergence rather than shared ancestry. By reinterpreting the systematic position of further taxa representing biogeographic enigma, such as Ogresuchus furatus , our phylogeny implies a major role of the primary breakup of Pangea into Laurasia and Gondwana for crocodyliform divergence. A critical reassessment of the purported evidence for ‘Gondwanan’ fish and tetrapod immigrants in Europe reveals that it is largely based on highly fragmentary and sporadic specimens, as well as weakly supported phylogenetic hypotheses. Given the sparse and uneven Jurassic and Cretaceous fossil record in both Europe and Africa, it remains plausible that taxa previously interpreted as Gondwanan dispersers instead represent vicariant relicts. Our results conflict with recent paleobiogeographic scenarios, highlight the absence of compelling evidence for the Eurogondwana hypothesis and instead support a primary Gondwana-Laurasia split.

Theropod teeth have long been known from the Upper Cretaceous of Europe, but the 20 million years long interval spanning the Cenomanian to the Campanian has remained underrepresented in the fossil record and understudied. Recent discoveries from the Turonian and Coniacian of Austria and the Santonian of Hungary fill this gap to some extent. Here we report on a study of 2D morphometry and dental wear of Turonian–Maastrichtian theropod teeth from Central Europe aimed at shedding further light on the phyletic and adaptive diversity of Late Cretaceous theropods in the archipelago of Europe. Our results suggest that the taxa Paraves indet. and Paronychodon were present in the region from the Turonian to the Maastrichtian, while medium-sized tetanuran forms are known only until the early Campanian. The record of some groups, such as troodontid or bird-like forms, is more sporadic and known only from a few sites. Dental wear study indicates that theropod teeth rarely show severe wear exposing dentin, though spalled surfaces are commonly seen on tetanuran teeth. Dental microwear feature and texture analysis of the worn enamel surfaces show a dominance of scratches (82–100%), with somewhat higher complexity in some of the non-serrated forms. The largest tetanuran teeth differ in terms of scratch length, pit size and anizotropy from the small, serrated Paraves indet. 1 teeth, but overlap with those of the extant carnivore-scavenger Varanus komodoensis suggesting large tetanurans resembled V. komodoensis in feeding on large vertebrates.

Ornithopod dinosaurs evolved numerous craniodental innovations related to herbivory. Nonetheless, the relationship between occlusion, tooth wear rate, and tooth replacement rate has been neglected. Here, we reconstruct tooth wear rates by measuring tooth replacement rates and tooth wear volumes, and document their dental microwear. We demonstrate that total tooth volume and rates of tooth wear increased steadily during ornithopod evolution, with deeply-nested taxa wearing up to 3360 mm³ of tooth volume/day. Increased wear resulted in asymmetric tooth crown formation with uneven von Ebner line increment width by the Late Jurassic, and in faster tooth replacement rates in multiple lineages by the mid-Cretaceous. Microwear displays a contrasting pattern, with decreasing complexity and pit percentages in deeply-nested and later-occurring taxa. We hypothesize that early ornithopods were browsers and/or frugivores but deeply nested iguanodontians were bulk-feeders, eating tougher, less nutritious plants; these trends correlate with increasing body mass and longer gut passage times.

Mesozoic amber cockroaches are rare compared to sedimentary imprints and are only known from Myanmar, Lebanon, France, Russia and USA. Perspicuus csincsii sp. n. from the Late Cretaceous (Santonian) ajkaite amber of Hungary with very long cerci, cup-like terminal palpomere of the maxillary palp and fully carinated legs, is clearly distinguished from all other Vitisminae species by the unique, black forewing with small light-coloured dots/stripes and the absence of pubescence on the wings (autapomorphies). The second cockroach described from the ajkaite adds important data to the distribution pattern of Vitisminae during the Late Cretaceous and further highlights the similarity of the ajkaite and burmite biotas.

The Rhabdodontidae was one of the most important dinosaur groups inhabiting the Late Cretaceous European Archipelago. Currently, the clade comprises nine species within six genera, which have been found in southern France, northern Spain, eastern Austria, western Hungary and western Romania, ranging from the Santonian to the late Maastrichtian. Phylogenetic analyses consistently place the Rhabdodontidae at the very base of the iguanodontian radiation, whereas the in-group relationships of rhabdodontids are relatively poorly understood; nevertheless, the clade seems to have had a rather complicated biogeographical history. Generally, rhabdodontids were small- to medium-sized, probably habitually bipedal herbivores, characterised by a rather stocky build and a comparatively large, triangular skull. Several lines of evidence suggest that they were presumably gregarious animals, as well as selective browsers that fed on fibrous plants and occupied different ecological niches than sympatric herbivorous dinosaur clades. Moreover, the sympatry of at least two rhabdodontid taxa was rather common and can be explained, at least in some instances, by niche partitioning. While rhabdodontids disappeared prior to the K/Pg extinction event in Western Europe, they survived close to the end of the Cretaceous in Eastern Europe, where they were amongst the last non-avian dinosaurs still present before the end of the Cretaceous. In this paper, we provide an overview of the rhabdodontid taxonomic history, diversity, phylogenetic relationships and palaeobiogeographic history, as well as palaeoecology and extinction. In addition, we also highlight still open questions on each of these topics and suggest potential future research directions.

Cockroaches (Blattaria s. str.) were documented from numerous amber localities around the world, representing both extinct and extant families. Alienopteridae is an extinct cockroach family known only from the Cretaceous of Gondwana (Brazil, Botswana, Myanmar amber) and the Cenozoic of North America. Alienopterix santonicus sp. n. from the Late Cretaceous amber of the Ajka Coal Formation (Bakony Mts, western Hungary) extends the rich geographical distribution of the family into Laurasia during the Mesozoic. As a member of the presumably pollinator cohort Alienopteridae, this species could have played an important role in the Ajka Coal ecosystem during the Santonian. The microrectangular structures of the forewing suggest that the new species likely possessed a metallic colouration already known from the group. Combined with the disruptive body pattern this could have served as an advanced camouflage. The microrectangular structures of the forewing were compared to integument microstructures of extant insects with metallic colouration. Various arthropod taxa are already known from ajkaite, and the new discovery further emphasizes the importance of this amber.

Dentitions of the sympatric herbivorous dinosaursHungarosaurus(Ankylosauria, Nodosauridae) andMochlodon(Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods—orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar inHungarosaurusandMochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However,Mochlodonpossesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning.Hungarosaurusis inferred to have eaten softer vegetation, whereasMochlodonlikely fed on tougher material. Compared to the much heavier, quadrupedalHungarosaurus, the bipedalMochlodonwore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.