Geochemical investigation of the mixed Máriahalom vertebrate fauna at the Paleogene–Neogene boundary in the Central Paratethys: environmental conditions and age constrain

The fossil vertebrate fauna of Máriahalom contains remains from a wide range of ecologies including terrestrial and aquatic mammals, crocodiles, sharks, and rays among others. All these were found mixed in mollusc-rich, shallow water, coastal deposits. The aim of the study is to trace the origin of the fossils using their rare earth element (REE) content and their respective ecology with stable oxygen isotopic compositions. In addition, marine vertebrates and calcareous marine fossils were analysed for their Sr isotope composition to provide a new age estimate for the locality. The REE content and their distribution in the fossils indicate similar early diagenetic environments and possible contemporaneous fossilization for the entire vertebrate assemblage. Reworked fossils of significantly different age can be excluded. The enamel/enameloid-derived phosphate oxygen isotope composition of selected fossil taxa fit well with previously inferred habitats that include marine, brackish, and terrestrial environments. Notably, the stem-pinniped Potamotherium valletoni is best interpreted as freshwater dweller instead of marine, consistent with the sedimentology of other occurrences. Our novel 87Sr/86Sr data suggest an Aquitanian age (21.4 ± 0.5 Ma) for the Máriahalom site that is younger than the previously proposed Late Oligocene age based on biostratigraphy (MP28–30 European Mammal Paleogene Reference Levels). An Aquitanian age raises the possibility that the index fossil taxon, the anthracothere mammal Microbunodon minimum, may have vanished earlier in Western Europe than in the Central Paratethys region

‘X’ marks the spot! Sedimentological, geochemical and palaeontological investigations of Upper Cretaceous (Maastrichtian) vertebrate fossil localities from the Vălioara valley (Densuş-Ciula Formation, Hațeg Basin, Romania)

At the beginning of the 20th century, the Croatian-Hungarian palaeontologist Ottokár Kadić discovered a rich Late Cretaceous vertebrate assemblage around Vălioara in the Haţeg Basin, including fossils of several dinosaurs and the proposed lectotype of the iconic basal eusuchian crocodyliform Allodaposuchus. These fossils were collected from seven main localities and have been housed in the collections of the Mining and Geological Survey of Hungary. However, the collection was mixed after World War II, and this unprovenanced material currently cannot be used for palaeoecological investigations. Nevertheless, the map marking the location of Kadić’s sites has been recently uncovered, showing the positions of the fossiliferous localities, which allows matching these with the historically collected specimens using geochemistry. Based on Kadić’s map, we georeferenced, relocated, and re-excavated these vertebrate-bearing outcrops, and documented their sedimentological context. Detailed stratigraphical investigations of the exposed successions indicate that this Vălioara material represents one of the oldest (= earliest Maastrichtian) Late Cretaceous faunal assemblages known from the Haţeg Basin. The vertebrate remains collected during our new excavations around Vălioara represent turtles (including Kallokibotion), crocodyliforms (Allodaposuchus, Doratodon, ‘Theriosuchus’, Acynodon), dinosaurs (Zalmoxes, Telmatosaurus, titanosaurs, theropods), and mammals. In order to determine potential geochemical differences among the sites, we selected several specimens with recorded stratigraphic position, measured their trace element compositions, and used these as independent proxies to assess the probable stratigraphic origin of the historical vertebrate fossils. Our detailed sedimentological, geochemical and palaeontological investigations around Vălioara contribute to a deeper understanding of the distribution, evolution and palaeoecology of the Haţeg vertebrate faunas during the latest Cretaceous

Geochemical analyses suggest stratigraphic origin and late Miocene age of reworked vertebrate remains from Penanjong Beach in Brunei Darussalam (Borneo)

We report on sporadic fossil vertebrates from Brunei Darussalam (Borneo). Most of these isolated remains are reworked and derive from Penanjong Beach known for former coastal cliffs used to be rich in marine molluscs. Previously, the only vertebrate remains reported were shark teeth. With new material, the fish fauna is now represented by six shark and a single ray taxa, while remains of three turtle families were discovered (Trionychidae, Cheloniidae, Geoemydidae). This fauna is compared to nearby upper Miocene fossiliferous beds from where remains of cheloniid and trionychid turtles were unearthed. To assess the origin of the reworked remains, rare earth element (REE) concentrations of the fossil bioapatite were compared between the reworked and the geographically closest in-situ Ambug Hill fauna. The obtained trend in REE variations are identical, revealing similar REE uptake mechanism and early diagenetic conditions. With the additional fact that the succession outcropping at Ambug Hill cuts the coastline imply that the majority of the reworked fossils derive from the local Miocene beds. This is supported by Sr-isotope ages from reworked calcite bivalve shells ranging from 9.74 to 6.62 Ma. These turtle remains thus represent the hitherto known first Neogene fossil tetrapods from Borneo

Geochemical analyses suggest stratigraphic origin and late Miocene age of reworked vertebrate remains from Penanjong Beach in Brunei Darussalam (Borneo)

We report on sporadic fossil vertebrates from Brunei Darussalam (Borneo). Most of these isolated remains are reworked and derive from Penanjong Beach known for former coastal cliffs used to be rich in marine molluscs. Previously, the only vertebrate remains reported were shark teeth. With new material, the fish fauna is now represented by six shark and a single ray taxa, while remains of three turtle families were discovered (Trionychidae, Cheloniidae, Geoemydidae). This fauna is compared to nearby upper Miocene fossiliferous beds from where remains of cheloniid and trionychid turtles were unearthed. To assess the origin of the reworked remains, rare earth element (REE) concentrations of the fossil bioapatite were compared between the reworked and the geographically closest in-situ Ambug Hill fauna. The obtained trend in REE variations are identical, revealing similar REE uptake mechanism and early diagenetic conditions. With the additional fact that the succession outcropping at Ambug Hill cuts the coastline imply that the majority of the reworked fossils derive from the local Miocene beds. This is supported by Sr-isotope ages from reworked calcite bivalve shells ranging from 9.74 to 6.62 Ma. These turtle remains thus represent the hitherto known first Neogene fossil tetrapods from Borneo

First report of Triassic vertebrate assemblages from the Villány Hills (Southern Hungary)

Abstract Remains of Triassic vertebrates discovered in the Villány Hills (SW Hungary) are described here. After the well-documented Late Cretaceous Iharkút locality, this material represents the second systematically collected assemblage of Mesozoic vertebrates from Hungary. Fossils were collected from both the classical abandoned road-cut at Templom Hill (Templom-hegy) and a newly discovered site at a construction zone located 200 meters west of the road-cut. Macrofossils of the construction site are mainly isolated bones and teeth of nothosaurs from the Templomhegy Dolomite, including a fragmentary mandible referred to as Nothosaurus sp. and placodont teeth tentatively assigned here to cf. Cyamodus sp. Affinities of these fossils suggest a Middle Triassic (Ladinian) age of these shallow marine deposits. New palynological data prove for the first time a Late Triassic (Carnian) age of the lower part of the Mészhegy Sandstone Formation. Vertebrate remains discovered in this formation clearly represent a typical Late Triassic shallow-marine fauna including both chondrichthyan (Lissodus, Palaeobates, Hybodus) and osteichthyan (cf. Saurichthys, ?Sphaerodus sp.) fish fossils. The presence of reworked nothosaur and placodont tooth fragments as well as of possible archosauriform teeth, suggest an increase of terrestrial influence and the erosion of underlying Triassic deposits during the Late Triassic. A belemnite rostrum collected from the lowermost beds of the Somssichhegy Limestone Formation proves that this Lower Jurassic (Pliensbachian) layer was deposited in a marine environment. Most of the vertebrate remains (nothosaurs, placodonts, hybodont shark teeth, perhaps Palaeobates, Lissodus) recovered from these beds are also reworked Triassic elements strongly supporting an erosive, nearshore depositional environment