Jodhpur, Nov. 25 -- Researchers have discovered sixteen nautiloid fossils from three different species in the Lower Eocene (approximately 56 to 47.8 million years ago) rocks of the Jaisalmer Basin, one of which is new, Angulithes rayi, named in honour of Satyajit Ray and inspired by his film Sonar Kella, which marked its 50th anniversary in 2024. These species are the first report of nautiloids from the Eocene marine rocks of the Jaisalmer Basin of Rajasthan. Lead researcher and Senior Research Fellow at the Geological Studies Unit of the Indian Statistical Institute, Kolkata, Adrisuta Ghosh, said, "The Lower Eocene strata of the Jaisalmer Basin have yielded a taxonomically diverse assemblage of molluscan and other invertebrate fauna. However, nautiloids remained undocumented from this region until now. The present study reports the occurrence of three nautiloid species, Eutrephoceras, Angulithes rayi and Angulithes, all recovered from a single, laterally restricted stratigraphic horizon within the lower part of the Te-Takkar Member of the Khuiala Formation." She added: "The concentration of a considerable number of specimens, encompassing multiple species, is exceptional in the Cenozoic record and suggests a parautochthonous assemblage with limited post-mortem transport. Integrated sedimentological, petrographic, and palaeoecological evidence indicates deposition in a low-energy, shallow-marine environment situated below a fair-weather wave base." According to the researchers, biomicritic lithology, along with an associated assemblage of larger benthic foraminifera (Operculina, Assilina) and molluscs (Venericardia, turritelline gastropods, and chemo symbiotic bivalves), suggests warm, sub-oxic, moderately nutrient-rich conditions on soft-bottom substrates in a middle-outer ramp environment. Evidence of single-flank encrustation on nautiloid shells indicates prolonged exposure at the sediment-water interface, likely under conditions of slow sedimentation and limited disturbance. The data provide new insights into early Eocene marine ecosystems of the Jaisalmer Basin in the western Indian margin....