Diversification following the end-Permian mass extinction marks the initiation of Mesozoic reptile dominance and of modern marine ecosystems, yet major clades are best known from the Middle Triassic suggesting delayed recovery, while Early Triassic localities produce poorly preserved specimens or have restricted diversity. Here we describe gen. et sp. nov. from the Early Triassic Nanzhang-Yuan'an Fauna of China assigned to Saurosphargiformes tax. nov., a clade known only from the Middle Triassic or later, which includes Saurosphargidae, and likely is the sister taxon to Sauropterygia. is allied to Saurosphargidae by the extended transverse processes of dorsal vertebrae and a low, table-like dorsal surface on the neural spine; however, it does not have the typical extensive osteoderms. Rather an unusual tuberous texture on the dorsal neural spine and rudimentary ossifications lateral to the gastralia are observed. Discovery of extends the known range of Saurosphargiformes and increases the taxic and ecological diversity of the Nanzhang-Yuan'an Fauna. Its small size fills a different ecological niche with respect to previously found species, but the overall food web remains notably different in structure to Middle Triassic and later ecosystems, suggesting this fauna represents a transitional stage during recovery rather than its endpoint.
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http://dx.doi.org/10.7717/peerj.13569 | DOI Listing |
Curr Biol
January 2025
Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
Dinosaurs dominated Mesozoic terrestrial ecosystems for ∼160 million years, but their biogeographic origin remains poorly understood. The earliest unequivocal dinosaur fossils appear in the Carnian (∼230 Ma) of southern South America and Africa, leading most authors to propose southwestern Gondwana as the likely center of origin. However, the high taxonomic and morphological diversity of these earliest assemblages suggests a more ancient evolutionary history that is currently unsampled.
View Article and Find Full Text PDFBMC Ecol Evol
January 2025
School of GeoSciences, University of Edinburgh, Edinburgh, Scotland.
Pterosaurs were the first vertebrates to evolve active flight. The lack of many well-preserved pterosaur fossils limits our understanding of the functional anatomy and behavior of these flight pioneers, particularly from their early history (Triassic to Middle Jurassic). Here we describe in detail the osteology of an exceptionally preserved Middle Jurassic pterosaur, the holotype of Dearc sgiathanach from the Isle of Skye, Scotland.
View Article and Find Full Text PDFNaturwissenschaften
January 2025
Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Av. Roraima 1000, 97105-900, Santa Maria, RS, Brazil.
This paper analyzes the paleoneurology (cranial endocast and maxillary canal) of Massetognathus pascuali, an iconic non-mammaliaform cynodont from the early Late Triassic of South America, using Neutron Tomography. The application of neutron tomography holds the potential for uncovering more refined anatomical and quantitative data. The newly examined cranial endocast shows a forebrain with a tubular shape without an interhemispheric fissure, presence of a pineal body (with a closed parietal foramen), and a marked unossified zone.
View Article and Find Full Text PDFNaturwissenschaften
January 2025
Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia Universidade Federal de Santa Maria (CAPPA/UFSM, Rua Maximiliano Vizzotto, 59897230-00, São João do Polêsine, Rio Grande do Sul, Brazil.
Prozostrodontia is a clade of probainognathian cynodonts that exhibit several morphological innovations later inherited by mammals. The earliest representatives of this group have been found in the Upper Triassic deposits of southern Brazil. In this study, we report the discovery of a probainognathian cynodont from the Buriol site (São João do Polêsine, Rio Grande do Sul, Brazil), Hyperodapedon Assemblage Zone (Late Triassic).
View Article and Find Full Text PDFiScience
December 2024
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, Sichuan, China.
To reveal the stratigraphic age of the Shiqianfeng Formation in the eastern continental basin of the North China Craton and the provenance of its sediments from the Late Carboniferous to the Early Triassic, six sandstone samples from the Puyang area were selected for zircon U-Pb dating. The result show that the Shiqianfeng Formation in the eastern North China Craton belongs to the Early Triassic. According to the age clusters of six samples, considering the regional geological setting and the distribution of zircon ages in the potential provenance area, it can be inferred that the Inner Mongolia Paleo-uplift provided continuous provenance supply for the study area during the Late Carboniferous-Early Triassic.
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