Soft-walled monothalamid foraminifera from the intertidal zones of the Lorn area, north-west Scotland

Recent advances in molecular phylogeny and increasing numbers of studies carried out worldwide in subtidal and deep-water marine sites have confirmed that monothalamid foraminifera represent a significant component of the marine benthos. Fewer studies have been carried out on monothalamids in littoral zones, and here I describe more than 13 novel morphotypes of soft-walled monothalamids found at several intertidal sites in the Lorn area of north-west Scotland. Samples of sediment were collected from these areas and monothalamid tests were removed from the mud by direct manipulation with brushes, by coverslip-capture, by capture with a magnet for those with magnetic particles or by extraction from mud balls. Attached forms of tests from the same sites were isolated from collected seaweed blades, pebbles and decaying shells. Monothalamids were observed live and photographed in their natural colours, followed by examination after preservation in alcohol and embedding in glycerol. The greatest diversity of species was found to be at estuaries near to the mouths of the sea lochs, and the abundance of some of the species varied with the time of the year, being different for each species. The observed taxa included a Vellaria sp. and Psammophaga sp., two allogromiids, three saccamminids and six undetermined species; each assemblage of specimens may have contained more than one species not readily discernible by morphological characteristics alone. Taxonomic parallels between the described specimens and those in reports for other parts of the world and in deeper waters in western Scotland are discussed.