The Cretaceous/Paleogene boundary records one of the key events in history of life, but not all clades were affected similarly. Albanerpetontidae, an extinct group of lissamphibians, appears to have been little impacted, yet their patchy Upper Cretaceous record in Europe, concentrated in the Santonian to the Maastrichtian, limits our understanding. For the last 20 years, the Ibero-Armorican Island has been one of the key areas for studying these stages; but despite several occurrences of albanerpetontids, none has been described in detail. Here we report a new albanerpetontid species from the upper Maastrichtian Blasi 2B locality (Huesca, Spain), based on disarticulated cranial and postcranial bones. Synorerpeton ribagorzana gen. et sp. nov. represents the first formally described Upper Cretaceous European albanerpetontid species. It is characterized by the orbital margin of the frontal located anterior to the anteroposterior midpoint of the bone, subrectangular atlas cotyles, a weakly curved posterior edge of the maxillary nasal process, and a large palatal foramen in the premaxillae. The latter trait is shared with ‘Albanerpeton’ galaktion from the Campanian of North America. Synorerpeton shows affinities with other Ibero-Armorican material but differs from eastern European taxa, suggesting two distinct albanerpetontid populations coexisted during the Late Cretaceous of Europe. Our results also support that Albanerpeton is polyphyletic. We recommend restricting the genus to a subset of species containing the type species A. inexpectatum and all species more closely related to it than to ‘A.’ nexuosum; thus, containing for now only both European Cenozoic species A. inexpectatum and A. pannonicum.
This study presents the first palynological analysis of the Río Belgrano Formation (Lower Cretaceous) at the El Águila locality, northern Austral-Magallanes Basin, Argentina. Twenty rock samples yielded well-preserved and taxonomically diverse palynological assemblages comprising 55 spore species, 32 pollen taxa, 16 dinoflagellate cyst species, and 13 other algal taxa. The assemblages are strongly dominated by terrestrial components (mean Continental/Marine index = 0.85), with a prominent dominance of the extinct gymnosperm pollen Classopollis (mean relative abundance = 71.1%), followed by subordinate Podocarpaceae, Araucariaceae, and trilete fern spores. Based on the presence of Clavatipollenites spp. and Cyatheacidites tectifera, alongside diagnostic marine dinoflagellate cysts such as Herendeenia postprojecta, Phoberocysta neocomica, Odontochitina operculata, a late Barremian age is assigned to the unit, though an early Aptian age for its uppermost levels cannot be ruled out. Multivariate Q-mode cluster analysis (CONISS) identified four distinct sample groups that partially correlate with regional flooding surfaces. Fluctuations in the continental-to-marine palynomorph ratio reflect relative sea-level changes within a sand-dominated deltaic system. The dominance of Classopollis spp. within the palynological assemblage suggests humid conditions, but with low-nutrient substrates and marked seasonality. The low relative abundance of spores, including Cyatheacidites tectifera (related to Lophosoria quadripinnata) supports humid to sub-humid local conditions under temperate to warm-temperate regimes.
New micropalaeontological investigations of four stratigraphic sections (Sealer Hill, Byers Camp, Zigzag Gully, and Chester Cone) within the Chester Cone Formation, Byers Group (Byers Peninsula, Livingston Island, Antarctica) yielded valuable calcareous dinocyst assemblages. Despite widespread recrystallisation, dinoflagellate cysts provide sufficient biostratigraphic resolution to identify three distinct zones: Carpistomiosphaera valanginiana (lower–upper Valanginian), Stomiosphaera echinata (upper Valanginian), and Cadosinopsis nowaki (lower Hauterivian). These data demonstrate that the marine sediments of the Byers Group possess a broader stratigraphic range than previously documented, indicating that marginal basin uplift within the Antarctic Peninsula volcanic arc occurred later and more rapidly than initially assumed. Crucially, this study reports the very first discovery of Cadosinopsis nowaki outside the Tethyan realm. The identified calcareous dinocyst assemblages exhibit strong palaeobiogeographic affinities with contemporaneous faunas from the Neuquén Basin in Argentina and the Tethyan realm. The presence of C. nowaki in Antarctica reveals a significantly wider palaeobiogeographic distribution for this species. Furthermore, it provides definitive evidence of a robust Early Cretaceous marine connection between the Tethys Ocean and the Antarctic region, likely facilitated simultaneously via the Spanish Corridor (or surface currents along the Andean coast), and the Mozambique Corridor.
Numerous isolated postcranial remains from the lower Campanian part of the Rybushka Formation in the Volga region of Russia (the Beloe Ozero and Shyrokii Karamysh localities) have been attributed to Pteranodon sp. This is based on the recognition of a new autapomorphy in the postcranial skeleton: a hypertrophied adductor ridge on the posterior side of the femur. In all other known pterodactyloids, this ridge is represented by a thin line. However, the cervical vertebrae from the upper Campanian part of the Rybushka Formation (Malaya Serdoba locality) differ from those of North American and Eastern European Pteranodon, and are instead attributed to Pteranodon orientalis (Bogolyubov, 1914). The vertebrate assemblages of the Rybushka Formation in Russia and the Coniacian-Campanian Niobrara Formation in the USA are similar in that they both contain the protostegid turtle Protostega gigas, the mosasaurs Clidastes propython and Latoplatecarpus, the pterosaur Pteranodon and the aquatic bird Hesperornis. This North American-like vertebrate assemblage is not found in the Late Cretaceous of Western Europe. The distribution range of Pteranodon during the Campanian period included the western margin of the Appalachian continent, the Volga region, and Japan. Pteranodon inhabited near-shore, shallow-water palaeoenvironments that were rich in fish. In contrast, Campanian azhdarchids were most prevalent in fluvial environments. However, they are also rarely found in marine localities alongside Pteranodon.
The Lower Cretaceous (Valanginian – Barremian) marlstone series in three outcrops (Moulay Bouchta, Jebel Meguedrouz, and Chrouf) of the western External Rif yielded 112 belemnite rostra. Although most of these rostra are incomplete, they allowed the identification of seventeen taxa belonging to five genera: Berriasibelus, Duvalia, Hibolithes, Pseudobelus, and Pseudoduvalia. All the identified taxa have been previously reported from the Valanginian – Barremian sequences of the northern margin of the Tethys and the Essaouira-Agadir Basin of western Morocco.
