A New Integrated Approach to Taxonomy: The Fusion of Molecular and Morphological Systematics with Type Material in Benthic Foraminifera

This work was supported by NERC grant NE4/G018502/1 and NE/G020310/1 (Website: http://www.nerc.ac.uk). The authors also thank the following for their support the Carnegie Trust for the Universities of Scotland (Website: http://www.carnegie-trust.org) and the Estuarine Coastal and Shelf Science Association (Website: http://www.ecsanews.org). M.S. was also supported by the Swiss National Science Foundation (SNSF), fellowships for advanced researchers PA00P2_126226 and PA00P2_142065 (Website: http://www.snf.ch/en/Pages/default.aspx).A robust and consistent taxonomy underpins the use of fossil material in palaeoenvironmental research and long-term assessment of biodiversity. This study presents a new integrated taxonomic protocol for benthic foraminifera by unequivocally reconciling the traditional taxonomic name to a specific genetic type. To implement this protocol, a fragment of the small subunit ribosomal RNA (SSU rRNA) gene is used in combination with 16 quantitative morphometric variables to fully characterise the benthic foraminiferal species concept of Elphidium williamsoni Haynes, 1973. A combination of live contemporary topotypic specimens, original type specimens and specimens of genetic outliers were utilised in this study. Through a series of multivariate statistical tests we illustrate that genetically characterised topotype specimens are morphologically congruent with both the holotype and paratype specimens of E. williamsoni Haynes, 1973. We present the first clear link between morphologically characterised type material and the unique SSU rRNA genetic type of E. williamsoni. This example provides a standard framework for the benthic foraminifera which bridges the current discontinuity between molecular and morphological lines of evidence, allowing integration with the traditional Linnaean roots of nomenclature to offer a new prospect for taxonomic stability.Publisher PDFPeer reviewe

Colonisation and bioerosion of experimental substrates by benthic foraminifers from euphotic to aphotic depths (Kosterfjord, SW Sweden)

In the cold-temperate setting of the Swedish Kosterfjord area, experimental carbonate and PVC substrates were deployed for a 6, 12 and 24-month duration along a transect from euphotic to aphotic depths in order to study bioerosion and carbonate accretion patterns. Among the organisms that contribute to the latter by secreting calcareous skeletons, epibenthic foraminiferans represent a major component, both in terms of diversity (a dozen species) as well as in the number of individuals (exceeding 50,000 individuals per m2 at certain depths). The by far dominating species were found to be Cibicides lobatulus and the agglutinating Lituotuba lituiformis, along with smaller numbers of Planorbulina mediterranensis, Tholosina vesicularis and Nubecularia lucifuga. The foraminiferal distribution exhibits a pronounced abundance maximum in shallow waters at 7 and especially 15 m and a maximum in diversity at 15-50 m water depth. Some of the foraminiferans encountered, such as Cibicides lobatulus and the rare Gypsina vesicularis, were found to contribute also to the bioerosion of the calcareous substrates by etching shallow attachment scars. These prominent traces witness the former presence of benthic foraminiferans on fossil to Recent hardgrounds, inferring a potential applicability as an in situ proxy where tests are not preserved. Estimated minimum carbonate production rates for the dominant Cibicides lobatulus reach a maximum of 0.326 g/m2/year with the highest rates occurring at 7 to 30 m water depth. Carbonate production rates are up to two magnitudes higher on the PVC (0-0.326 g/m2/year) than on the carbonate substrates (0-0.010 g/m2/year) and are considerably higher than estimates previously reported from the western Baltic