title: Selective zircon accumulation in a new benthic foraminifer, Psammophaga zirconia, sp. nov.
abstract: Benthic foraminifera are single-celled eukaryotes that make a protective organic, agglutinated or calcareous test. Some agglutinated, single-chambered taxa, including Psammophaga Arnold, 1982, retain mineral particles in their cytoplasm, but the selective mechanism of accumulation is not clear. Here, we report the ability of a foraminiferal species to select and accumulate zircons and other heavy minerals in their cytoplasm. In particular, the use of Scanning Electron Microscope coupled with an Energy Dispersive X-ray microanalysis system (SEM-EDS) enabled a representative overview of the mineral diversity and showed that the analysed Psammophaga zirconia sp. nov. individuals contained dominantly crystals of zircon (51%), titanium oxides (27%), and ilmenite (11%) along with minor magnetite and other minerals. The studied specimens occur in the shallow central Adriatic Sea where the sediment has a content of zircon below 1% and of other heavy minerals below 4%. For that reason we hypothesize that: (i) P. zirconia may be able to chemically select minerals, specifically zircon and rutile; (ii) the chemical mechanism allowing the selection is based on electrostatic interaction, and it could work also for agglutinated foraminifera (whether for ingestion, like Xenophyophores, or incorporation in the test as in many other described taxa). In particular, this aptitude for high preferential uptake and differential ingestion or retention of zircon is reported here for the first time, together with the selection of other heavy minerals already described in members of the genus Psammophaga. They are generally counted among early foraminifera, constructing a morphologically simple test with a single chamber. Our molecular phylogenetic study confirms that P. zirconia is a new species, genetically distinctive from other Psammophaga, and occurs in the Adriatic as well as in the Black Sea.
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente Di.S.V.A., Università Politecnica delle Marche, Ancona, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Sabbatini
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente Di.S.V.A., Università Politecnica delle Marche, Ancona, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Negri
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, UMR 7207 CNRS MNHN UPMC, Muséum National d'Histoire Naturelle, Paris Cedex 05, France.
authors.forename: A
authors.initials: A
authors.lastname: Bartolini
authors.affiliation: Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Morigi
authors.affiliation: ISTEP (UMR 7193), Université Pierre et Marie Curie, Paris Cedex 05, France.
authors.forename: O
authors.initials: O
authors.lastname: Boudouma
authors.affiliation: Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Dinelli
authors.affiliation: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Roma, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Florindo
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente Di.S.V.A., Università Politecnica delle Marche, Ancona, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Galeazzi
authors.affiliation: Department of Genetics and Evolution, Université de Genève, Geneva 4, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Holzmann
authors.affiliation: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Roma, Italy.
authors.forename: P C
authors.initials: PC
authors.lastname: Lurcock
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente Di.S.V.A., Università Politecnica delle Marche, Ancona, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Massaccesi
authors.affiliation: Department of Genetics and Evolution, Université de Genève, Geneva 4, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Pawlowski
authors.affiliation: Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Rocchi
mesh_terms: D016000:Cluster Analysis; D003593:Cytoplasm / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D056908:Foraminifera / Q000737:chemistry* / Q000145:classification* / Q000166:cytology; D020459:Genes, rRNA; D008522:Mediterranean Sea; D019216:Metals, Heavy / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000032:analysis; D010802:Phylogeny; D016053:RNA, Protozoan / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013052:Spectrometry, X-Ray Emission; D015040:Zirconium / Q000032:analysis*
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D019216:Metals, Heavy; D008903:Minerals; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S; D015040:Zirconium; C028541:zirconium oxide