Staurastrum tectum var. ayayense Grönblad

Staurastrum tectum var. ayayense Grönblad *

( Fig. 7E View FIG )

Acta Societatis Scienctiarum Fennicae, Nova Series B, 2 (6): 31 ( Grönblad 1945).

DISTRIBUTION. — France, Brazil. Amazon Basin: Grönblad (1945); Förster (1969, 1974); Thomasson (1971, 1977); Uherkovich (1976, 1981); Uherkovich & Rai (1979); Martins (1986a); Melo & Souza de (2009). Western Amazonia (lowlands): no records.

DESCRIPTION

Cells 27.1-31.7 µm long, 67.6-93.0 µm wide with processes, isthmus: 7.8-9.6 µm. The basal margin of the inverted triangular semicells features a single granule with two to three teeth positioned just above the isthmus, while the upper margin is indented in the middle. Each angular process boasts a nearly horizontal, diverging spine and an emarginate granule at its base. The processes are slender, long, and diverging, with toothed margins culminating in two or three denticles.

REMARKS

Specimens from this taxon are variable in shape, particularly on the curvature of processes. Like our specimens, Förster’s (1974) hold two or three denticles at the tip of each process.