Monothalamous (single-chambered) foraminifera comprise a poorly known group, the diversity of which is strongly underestimated according to environmental DNA surveys. The gross morphology of monothalamids offers few distinguishing features; their organic-walled or agglutinated tests are often very delicate and make isolation difficult. Here, we use an integrated taxonomic approach, including morphological and molecular analysis, to examine the diversity of monothalamids in a shallow subtidal area on the coast of Iceland. We report nine new phylotypes of single-chambered foraminifera distinguished by SSU rDNA sequences. Among them, we establish a new genus Flexammina and a new species Flexammina islandica, possessing a very pliable, finely agglutinated test capable of extreme shape transformations. According to molecular data, F. islandica belongs to the monothalamid clade M, which also includes the well-known genus Allogromia. In addition, we provide brief descriptions and illustrations of nine other monothalamous foraminifera isolated from the same area. Three of them are closely related to some unidentified environmental sequences and serve as the first microscopic documentation of these anonymous lineages.
A small planispiral rotaliid, Nonion? niveum, was described by Lafrenz from the Eemian (upper Pleistocene) of the Baltic Sea. Since then, the species has several times been attributed to other genera (Haynesina, Protelphidium), resulting in taxonomic confusion. Recently, a morphologically identical foraminifer has been found in the White Sea, which is the first documented occurrence of the species from this area. In-depth investigation of its test morphology revealed that the species has features common to modern Haynesina representatives and particularly to the extinct Paleogene species Protelphidium hofkeri. This was especially evident in the architecture of the umbilical area. With the help of a comparative morphological study of several other elphidiids, the species in question was attributed to the genus Protelphidium, as its only living member and with the necessary emendation of the diagnosis. We believe that the redescription of Protelphidium niveum helps to clarify the taxonomy of the basal ''lower'' elphidiids by coupling the revision of morphological features with molecular data.
Textulariid foraminifera are characterized by a multichambered test with an agglutinated wall structure. Recent molecular work has shown that the order Textulariida appears as a paraphyletic group within the class Globothalamea. While larger members of the textulariids are fairly well known, smaller forms like the ones described here are often overlooked or synonymized with known species. A new species and genus was isolated from algal samples collected on the French coast of the Mediterranean Sea. Cyrea szymborska gen. and sp. nov., has a trochospiral chamber arrangement, measuring 100–210 µm in diameter. The organic wall is brownish, opaque, and sparsely agglutinated with diatom frustules and mineral grains, mostly 20 µm or smaller in size. The proloculus is not agglutinated. The extra-umbilical aperture forms a low arch. It is smooth, not agglutinated, and located on the last chamber. The biochemistry of the organic wall was investigated using Raman spectroscopy, showing that it is made of a meshwork of proteoglycans. A combined analysis of SSU and LSU rDNA sequences confirms the position of Cyrea among textulariids, distantly from all other genera. Molecular analyses revealed two phylotypes belonging to the new genus, one of which is formally described here.
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