Morphological and molecular taxonomies of planktonic foraminifera : design of a taxonomic framework and special cases of Globigerinoides sacculifer and Neogloboquadrina pachyderma

Morphospecies of planktonic foraminifera are clusters of eco-genotypes that show small but significant shell morphological differences (pseudo-cryptic species).This discovery opens a new perspective for improving the accuracy and resolving power of paleoceanographic reconstructions. Unfortunately, c...

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Bibliographic Details
Main Author: André, Aurore
Other Authors: Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard - Lyon I, Frédéric Quillévéré, Gilles Escarguel, Thibault de Garidel-Thoron
Format: Doctoral or Postdoctoral Thesis
Language:French
Published: HAL CCSD 2013
Subjects:
Planktonic foraminifera
Taxonomic units
ABGD
GMYC
SSUrDNA and ITSrDNA
Biogeography
Morphometry
Ecophenotypes
Foraminifères planctoniques
Unités taxonomiques
SSUrDNA et ITSrDNA
Biogéographie
Morphométrie
Écophénotypes
[SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Austral
Découverte
Neogloboquadrina pachyderma
Online Access:https://theses.hal.science/tel-01048643
https://theses.hal.science/tel-01048643/document
https://theses.hal.science/tel-01048643/file/TH2013_Andre_Aurore_V_Expurgee.pdf
Description
Summary:Morphospecies of planktonic foraminifera are clusters of eco-genotypes that show small but significant shell morphological differences (pseudo-cryptic species).This discovery opens a new perspective for improving the accuracy and resolving power of paleoceanographic reconstructions. Unfortunately, current genetic type delimitations suffer subjectivity, inducing non-homogenous taxonomic status while homogenous taxonomic status is a prerequisite for including genetic types in reconstruction models. By applying quantitative and complementary methods for taxonomic units delimitation to the available dataset of partial sequences of SSU (ribosomal small sub-unit), we delimited 49 genuine (pseudo)cryptic species of planktonic foraminifera. We studied two paleoceanographic key-species. Complete sequencing of the SSU and morpho-genetic comparison within austral (sub)polar genetic types of Neogloboquadrina pachyderma lead to a new phylogeographic hypothesis and showed that morphological variations are the result of ecophenotypic effects and are not related with genetic types. The morphologically diverse Globigerinoides sacculifer is the first case of a planktonic foraminifera morphospecies corresponding to a single genetic type distributed world-wide in (sub) tropical waters. These two cases show that, contrary to previous studies conclusions, pseudo-cryptic speciation is not a rule within planktonicForaminifera Les morpho-espèces de foraminifères planctoniques sont composées d'éco-génotypes parfois différentiables sur la base de la morphologie de leur coquille. Cette découverte récente d'une diversité ainsi qualifiée de « pseudo-cryptique » ouvre des perspectives d'amélioration de la précision des reconstructions paléocéanographiques. Malheureusement, ces génotypes ont été définis de façon subjective et ne sont pas homogènes quant à leur rang taxonomique, ce qui est pourtant un pré-requis pour leur intégration dans les modèles de reconstruction. Grâce à l'application de méthodes quantitatives de délimitation d'unités ...

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