Genus Pterocystis Siemensma & Roijackers, 1988

Diagnosis: Centrohelea with a periplast with tangential plate scales and radial scales; radial scales consist of a shaft and a thin, membranous basal region which may extend along the shaft and may form a stalk-like protrusion at the base of the spicule. The membranous region is not clearly differentiated into lateral and basal regions as in Echinocystis.
Type species: Pterocystis pteracantha (Siemensma, 1981) Siemensma & Roijackers, 1988
Reference: Mikrjukov (1997).

Though it is very difficult to identify heliozoans light microscopically, it is still possible to identify the genus and sometimes the species. It might be helpful to dry a specimen. These dried scales are probably from Echinocystis erinaceoides.
Recent posts

Difflugia acuminate tests

Acuminate tests Tests with one or more spines or bud-like or conical protuberances or just a pointed fundus D. acuminata D. congolensis D. ventricosa D.

Read More »

Difflugia subaequalis

Difflugia subaequalis, from Penard, 1910 Difflugia subaequalis  Penard, 1910 Diagnosis: Test almost spherical, slightly elongated, with a wide pseudostome, almost as wide as the test

Read More »

Difflugia spherical tests

 Difflugia ampullula, after Playfair, 1918  Difflugia ampullula  Playfair, 1918 Diagnosis: Test broadly ovate, with hemispherical fundus, and sides gradually converging in almost straight lines to

Read More »

Difflugia stepaneki

Difflugia stepaneki, from Hager and Haagerova, 1970 Difflugia stepaneki  Hager and Haagerova, 1970 Diagnosis: Test broad elliptical, circular in cross-section, with a short neck that

Read More »