A new proxy for Cretaceous paleoceanographic and paleoclimatic reconstructions: Coiling direction changes in the planktonic foraminifera Muricohedbergella delrioensis

• Published in: Palaeogeography, Palaeoclimatology, Palaeoecology
• Main Authors: Desmares, Delphine, Crognier, Nemo, Bardin, Jérémie, Testé, Marc, Beaudoin, Bernard, Grosheny, Danièle
• Other Authors: Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Fluides Complexes et leurs Réservoirs (LFCR), TOTAL FINA ELF-Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS), Centre de Géosciences (GEOSCIENCES), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), GeoRessources, Institut national des sciences de l'Univers (INSU - CNRS)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Planktonic foraminifera; Coiling direction; Oceanic Anoxic Event 2; Western Interior Seaway; Sea Surface Temperature; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
• Online Access: https://hal.sorbonne-universite.fr/hal-01259877; https://hal.sorbonne-universite.fr/hal-01259877/document; https://hal.sorbonne-universite.fr/hal-01259877/file/Desmares_A_new_proxy_for.pdf; https://doi.org/10.1016/j.palaeo.2015.12.021

International audience Among some modern and recent fossil species of planktonic foraminifera, the proportion of left-to right-coiled shells in a population appears to be temperature-dependent; the relative abundance of each morphotype reflecting ecological preferences. A similar relationship is identified among Muricohedbergella delrioensis (Carsey, 1926) at the Cenomanian-Turonian stage boundary in mid-latitude sites of the Western Interior Seaway, including the Pueblo type section. The increase of sinistral M. delrioensis in the assemblage is related to higher  18 O carb values and decrease in inner porosity which suggests that changes in the coiling direction in this morphospecies could represent a new proxy for constraining Sea Surface Temperature (SST) variations. As surface dwellers, muricohedbergellids were not ACCEPTED MANUSCRIPT 2 affected by Oceanic Anoxic Event (OAE2) and provide a continuous paleoclimatic signal throughout the Cenomanian-Turonian boundary interval. Furthermore, genetic evidence obtained from extant foraminifera indicates that shifts of coiling ratios in planktonic foraminifera species can express the signature of distinct genetic types, which are revealed through their opposite coiling directions. Coiling direction could be a genetic trait, implying that cryptic species may occur in the Mesozoic.