Capsammina patelliformis Gooday, Aranda da Silva, Koho, Lecroq and Pearse, 2010
Class Polythalamea
Order Allogromiida
Family Allogromida incertae sedis
Genus Capsammina Gooday, Aranda da Silva, Koho, Lecroq and Pearse, 2010
Species Capsammina patelliformis Gooday, Aranda da Silva, Koho, Lecroq and Pearse, 2010
Capsammina patelliformis, occurs mainly at bathyal (1000-3400 m) water depths in the Nazaré Canyon off Portugal. The test is strongly flattened, up to 500 μm or more in maximum dimension, and 30-80 μm thick. It lacks obvious apertures, and is typically composed of 2-3 large, plate-like grains of mica that form the upper and lower surface of the test; these are separated by fine-grained, white agglutinated material (‘mortar’) forming a ring around the cell body. The cytoplasm, visible through the mica plates, is whitish in colour with few obvious inclusions. Analysis of a fragment of the SSUrDNA gene indicates that C. patelliformis belongs in a clade branching with Crithionina delacai, C. granum and an undetermined crithioninid species. However, the divergences between the new species and these Crithionina species range from 20% to 21%, and are therefore too high to classify it in the same genus. We also transfer a previously described species, Psammosphaera bowmanni Heron-Allen and Earland 1912, to Capsammina based on its use of mica flakes in test construction. Other monothalamous agglutinated foraminifera, including Psammosphera spp., are phylogenetically distant from Capsammina. The new species occupies a shallow infaunal microhabitat, living mainly in the top 0.5 cm of sediment.
Plate I.
A, C-F. Transmitted light photographs B. SEM photograph of bottom right-hand specimen in Fig. A. F. Photograph showing cell body with inclusions.
scale bars = 100 μm
Type location: Nazaré Canyon 3536 m.
Plate II.
A-F Transmitted light and SEM micrographs of the same three specimens, viewed lying flat. G-I H is an oblique view and I an edge view of the specimens shown in G.
scale bars = 100 μm
Plate III.
A-C Edge view of specimen at progressively higher magnifications. D-E General view and detail of agglutinated ‘mortar’. F-G General view and detail of mortar of second specimen.
scanning electron micrographs; scale bars = 100μm except where indicated otherwise.
Phylogenetic tree based on SSU rDNA partial sequences showing the position of Capsammina patelliformis gen. et sp. nov. among the Foraminifera.
