Foss. Stud., Volume 4, Issue 1 (March 2026) – 7 articles

This research provides a new comprehensive assessment of Pikimachay Cave fossil remains of extinct fauna from the Late Pleistocene and Early Holocene, curated in the Florida Museum of Natural History’s Environmental Archaeology Program collections. The collection is the result of excavations carried out by Richard MacNeish during the 1960s and 1970s, during which he proposed pre-Clovis dates for human occupation in South America. Archival records housed across three institutions were compiled to reconstruct the spatial distribution of megafauna within the cave. Taphonomic observations of the bone assemblage were conducted to better understand depositional processes and cave conditions. Based on the spatial distribution of fossil evidence mapped and documented by layer and the taphonomic evidence of the bone assemblage, we conclude that the cave functioned primarily as a giant ground sloth burrow, also used by humans and carnivores. Future research, including additional radiocarbon dates and better contextualization of the deposits, will be essential for better understanding the fossil fauna represented in the cave and the ecological relationships among humans, carnivores and extinct species in the highlands of Perú. Full article

Nanxiong Basin (Guangdong Province, southern China) preserves one of the most complete nanhsiungchelyid turtle records from the latest Cretaceous in Asia. In this study, we review nanhsiungchelyid remains recorded from Nanxiong Basin within a refined stratigraphical framework. Nanhsiungchelyids show constant occurrence in the Nanxiong Basin, recorded from most formations of the Nanxiong Group, with their probable last occurrence close to the Cretaceous–Paleogene boundary. Full article

The Cretaceous dinosaur record from Normandy, in NW France, is reviewed. It includes several enigmatic specimens that were briefly mentioned in short notes published during the 19th and 20th centuries that have since then been destroyed in World War II or lost. Since they were neither described in detail nor illustrated, their identification must remain uncertain, but some may have been ankylosaur remains, while another specimen may have belonged to a bird or a non-avian theropod. Specimens that were properly described and are kept in museums in Normandy come from Albian and Cenomanian horizons in the coastal cliffs of Seine-Maritime. The Albian record, from Cape La Hève (Le Havre) includes an incomplete titanosaurian sauropod skeleton, described as Normanniasaurus genceyi, and an isolated caudal vertebra from the same provenance, probably belonging to that taxon. The Cenomanian record is limited to a group of bones and a tooth of the furileusaurian abelisaurid theropod Caletodraco cottardi from the glauconitic Chalk at Saint-Jouin-Bruneval. All these specimens come from marine sediments and are in all likelihood derived from floating carcasses that drifted over a fairly long distance from an emergent land area corresponding to the Armorican massif in the west. Although scanty, the record from Normandy sheds some light on the poorly known dinosaurs that inhabited north-western Europe during the middle part of the Cretaceous, some of which apparently had Gondwanan affinities. Full article

Palynological analysis of seventy-seven cutting samples from six boreholes in the Marañón Basin (northeastern Peru) has identified five distinct Neogene marine incursion events (ME-1 to ME-5), challenging existing models that depict them as short-lived episodes. The diverse palynological assemblages, comprising spores, pollen, freshwater algae, and critical marine indicators—including dinoflagellate cysts, foraminiferal test linings, and copepod eggs—reveal that these incursions were protracted and recurrent, each associated with a maximum flooding surface and bounded by intervals of continental sedimentation. The stratigraphic record shows the earliest event ME-1 (Aquitanian to Late Burdigalian, 23.03–17.7 Ma) identified across all studied wells. ME-2 (latest Burdigalian to Middle Langhian, 17.0–16.1 Ma) is also recorded basin-wide. ME-3 (latest Burdigalian to earliest Langhian 16.5–15.7 Ma) registered in two wells. ME-4 (Late Langhian to latest Serravallian, 14.6–11.62 Ma) registered in only two wells and ME-5 (Early Tortonian, 11.6–10 Ma) is documented exclusively in the southernmost well, culminating in Zanclean (~5.5–3.6 Ma) mangrove development. We interpret the ingress routes for ME-1 to ME-3 to be westward via the Marañón Portal or northward from the Caribbean, associating them with the Proto-Pebas and Pebas systems. In contrast, ME-4 would also be from Amazon trunk or Paraná Portal associated with the Pebas Phase, and ME-5 likely originated from the south through the Paraná Portal, linking it to the Acre Phase. These results demonstrate that Miocene marine incursions into western Amazonia were not brief episodes but represented prolonged periods of marine influence, facilitated by sustained subsidence in the Marañón retro-arc foreland basin. This history reveals a dynamic connectivity throughout the Neogene, with marine conditions acting as persistent biogeographic barriers that critically shaped the region’s Miocene biodiversity patterns. This refined chronology provides a comprehensive regional framework, significantly advancing our understanding of Amazonian paleogeography. Full article

Microscopes have long been an important tool for paleontology, but most researchers use biological microscopes that are designed for transmitted light illumination. Micropaleontology has traditionally involved investigations of individual organisms (e.g., foraminifera, radiolarian and diatoms), or fossil pollen. Optical microscopy can also be a useful method for the study of macrofossils. Polarized light illumination, long a mainstay of geological research, has largely been missing from paleontology investigations. However, adapting a standard microscope for polarized light is not a difficult task. The preparation of mineralized fossils as petrographic thin sections greatly expands the possibilities for microscopic examination of macrofossils. Scanning electron microscopy (SEM) has long been used for the study of fossils, most commonly for observing individual microfossils or anatomical features of larger organisms. X-ray fluorescence analysis (SEM/EDS), a standard method for geology research, has had minimal use by paleontologists, but it is a method that merits wider acceptance. This paper emphasizes inexpensive methods for researchers who want to expand their microscopy horizons without needing deep funding or access to specialized facilities. Full article

Marine deposits in western Europe provide insight into the interplay between the warm Tethys and cooler Boreal domains, offering a climatic context for the radiation of Early Jurassic species. Reconstructions of temperature for the Hettangian and Sinemurian periods are scarce, with inferred marine temperatures of 15–20 °C based on δ¹⁸O values, which are lower than those of subsequent Jurassic stages. This emphasizes the necessity for supplementary data in order to enhance our comprehension of the climatic dynamics that characterized the Early Jurassic period. This study analyses 75 invertebrate samples, including 53 specimens of Gryphaea arcuata, from Early Sinemurian marine sediments in the Fresville quarry, Normandy, France. The present study employs a multi-proxy approach, utilizing δ¹³C and δ¹⁸O values in conjunction with Sr and Mg contents, to assess the processes of fossil diagenesis, marine productivity, and seawater temperatures. Significant post-depositional alteration was observed in the geochemical compositions of 22 bivalve shells assigned to the genera Pseudolimea, Plagiostoma, and Chlamys, which were originally composed of aragonite, except for the outer layer, which is made of calcite. However, the low-Mg calcite shells of Gryphaea arcuata, which are renowned for their diagenetic resistance, retained the majority of their isotopic integrity. The results of the statistical analyses indicate that there was minimal late pervasive diagenesis involving meteoric waters at Fresville. This is in accordance with the typical decrease in δ¹³C, δ¹⁸O values, and Sr and Mg contents that such processes would otherwise cause. Published isotopic data from Sinemurian marine fossils (plesiosaur and shark teeth) were used to estimate seawater δ¹⁸O (~−1‰ VSMOW) and surface temperatures (~24 °C). The calculated benthic temperatures of Gryphaea (17 °C) correspond to habitats at depths of about 50 m. These findings suggest a positive hydrological balance and euhaline conditions in a humid tropical climate context. Full article