The genetic diversity, morphology, biogeography, and taxonomic designations of Ammonia (Foraminifera) in the Northeast Atlantic

• Published in: Marine Micropaleontology
• Main Authors: Bird, Clare, Schweizer, Magali, Roberts, Angela, Austin, William E.N., Knudsen, Karen Luise, Evans, Katharine, Filipsson, Helena, Sayer, Martin D.J., Geslin, Emmanuelle, Darling, Kate
• Other Authors: Université d'Angers (UA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Ammonia; Genetic types; Morphometrics; Biogeography; Taxonomy; [SDE]Environmental Sciences; Hayward; Northeast Atlantic
• Online Access: https://hal.univ-angers.fr/hal-03118521; https://doi.org/10.1016/j.marmicro.2019.02.001

International audience The genetic diversity, morphology and biogeography of Ammonia specimens was investigated across the Northeast (NE) Atlantic margins, to enhance the regional (palaeo)ecological studies based on this genus. Living specimens were collected from 22 sampling locations ranging from Shetland to Portugal to determine the distribution of Ammonia genetic types across the NE Atlantic shelf biomes. We successfully imaged (via scanning electron microscopy, SEM) and genotyped 378 Ammonia specimens, based on the small subunit (SSU) rRNA gene, linking morphology to genetic type. Phylogenetic analyses enabled identification of seven genetic types and subtypes inhabiting the NE Atlantic margins. Where possible, we linked SSU genetic types to the established large subunit (LSU) T-type nomenclature of Hayward et al. (2004). SSU genetic types with no matching T-type LSU gene sequences in GenBank were allocated new T-numbers to bring them in line with the widely adopted T-type nomenclature. The genetic types identified in the NE Atlantic margins are T1, T2, T3, T6, and T15, with both T2 and T3 being split further into the subtypes T2A and T2B, and T3S and T3V respectively. The seven genetic types and subtypes exhibit different biogeographical distributions and/or ecological preferences, but co-occurrence of two or more genetic types is common. A shore-line transect at Dartmouth (South England) demonstrates that sampling position on shore (high, middle or low shore) influences the genetic type collected, the numbers of genetic types that co-occur, and the numbers of individuals collected. We performed morphometric analysis on the SEM images of 158 genotyped Ammonia specimens. T15 and the subtypes T3S and T3V can be morphologically distinguished. We can unequivocally assign the taxonomic names A. batava and A. falsobeccarii to T3S and T15, respectively. However, the end members of T1, T2A, T2B and T6 cannot be unambiguously distinguished, and therefore these genetic types are partially cryptic. However, we ...