Microworld

world of amoeboid organisms

Menu

Pterocystidae  Cavalier-Smith and Von der Heyden, 2007

Diagnosis: Periplast ancestrally with two contrasting types of siliceous scales:
1 Tangential plate-scales (margin not hollow and inrolled but sometimes thickened) oval, sometimes slightly (rarely markedly) narrower at one end, sometimes slightly indented on one side (rarely slightly on both) but never distinctly bi-lobed;
2 Bipartite radial spine-scales typically consisting of a leaf-like blade with an axial rib, usually extended apically as a projecting needle-like point (blunt or pointed, but not branched), and lateral wings; radial scale-base may be rounded or truncated and may be in the same plane as the blade or somewhat bent away from it (Pterocystis) or markedly extended as a distinct shelf or basal disc (sometimes called basal wing: Mikrjukov, 2002) orthogonal to the main blade (Raineriophrys); species with a pronounced basal wing may have lateral wings that are greatly reduced or absent; if silica scales are rarely secondarily missing (Chlamydaster), the cell has a distinct mucous coat; funnel-shaped scales absent.
Type genus: Pterocystis.
   
Included genera: 
   
Pterocystis  Siemensma and Roijackers, 1988
Raineriophrys  Mikrjukov, 2000
Chlamydaster  Rainer, 1968
   
The distinction between Raineriophrys and Pterocystis is not sharp; molecular and ultrastructural investigation of all other Raineriophrys species is needed to check whether Raineriophrys is monophyletic and deserves generic distinction.

Recent posts

Kibisidytes

K. marinus, after Jepps, 1934 Kibisidytes marinus Jepps, 1934 Diagnosis: Small amoeboid organism occurring in the sea, attached to the surface film or to some

Read More »

Phaeobola

P. aeris from Dumack et al., 2000 Phaeobola Dumack et al., 2000 Diagnosis: Cells roundish to oval shaped. Shell colorless to amber-colored, rough surface, few

Read More »

Rhizaspis armata

R. armata, 68 µm long, excl. spines – Laegieskamp Rhizaspis armata (Lauterborn, 1901) Dumack et al., 2021 Basionym: Pamphagus armatum Lauterborn, 1890 Diagnosis: Theca membranous,

Read More »

Rhizaspis spinosa

The original description with original drawings, Penard, 1890. Rhizaspis spinosa (Penard, 1890) Dumack et al., 2021 Basionym: Trinema spinosum Penard, 1890 Diagnosis: Theca membranous, ovoid

Read More »

Difflugia “pseudoclaviformis”

Difflugia “pseudoclaviformis”, front and side view, 424 µm Difflugia “pseudoclaviformis” Diagnosis: Shell pyriform, compressed, with a more or less pronounced aboral protuberance; shell composed of

Read More »

Difflugia from Lolo Pass

Shells 461-448 µm, stacked image. I found this large en remarkable shells in sediment of a small mountain lake near Lolo Pass, Montana USA. It differs

Read More »

Foraminifer drome

Unknown species, collected from the river Drôme, France, 2021 Unknown species September 2021, I found about ten specimens of an agglutinated foraminifer in a sample

Read More »

Cyclopyxis spec

Cyclopyxis spec., 168 µm Cyclopyxis spec. Diagnosis: Shell circular in ventral and dorsal view, more or less hemispherical in lateral view (height/diameter ≈ 0.5); lateral

Read More »

Difflugia fallax

Difflugia fallax, from Penard, 1902 Difflugia fallax Penard, 1890 Diagnosis: Shell hyaline or yellowish-greenish, black at low magnification, round in cross section, formed of a

Read More »