Genus Luffisphaera Belcher & Swale, 1975
Diagnoses: Cells spherical or elliptical, size range ca. 2.5-3.5 µm. Periplast covered with a single layer of hollow, lattice-work scales. The majority of these consist of a bowl-shaped lower part with a thickened base supporting a cylindrical, fusiform or dome-shaped outer portion. Some scales possess the basal part only. No cilia or basal bodies observed. Single large nucleus present.
Remarks: The nucleus occupies a large part of the cell. It has a conspicuous nucleolus and the double membrane of the wall is clearly visible. The mitochondria, several in each cell, contain microtubular cristae, and a Golgi apparatus and associated vesicles are always present. The cytoplasm contains numerous vesicles and channels of e.r. Several vacuoles which may be food vacuoles are also present, but no recognizable contents were seen. The cell membrane is often invaginated to form small channels, perhaps in connection with pinocytosis. There was no indication of either cilia or basal bodies.
The affinities of the organisms are obscure. They might be thought to be spores, but there are no signs of encapsulation and the content’s seem typical of active cells. Despite the apparent absence of cilia there is no evidence of pseudopodial production and the cells are presumably non-motile. Recent studies have shown a great diversity of scale structure among micro-organisms, but the only scales in the least resembling those of Luffisphaera are on Sphaleromantis tetragona Skuja (Manton & Harris 1966), a motile photosynthetic member of the Chrysophyceae or Chrysomonadida, Species of Luffisphaera may be widespread. They are not confined to freshwater since a cell apparently belonging to the group (and most like our form A) has been seen among the marine plankton off the Danish coast (Manton, in the press).
All from Belcher and Swale, 1975