Euastrum subcyclopicum var. elongatum Thérézien (1985: 82)

Ramos, Geraldo José Peixoto, Costa, Fabiana De Matos, Santos, Maria Aparecida Dos & Moura, Carlos Wallace Do Nascimento, 2019, Taxonomic novelties, new records, and rare species of desmids from the Chapada Diamantina region, Brazil, Phytotaxa 391 (3), pp. 185-196 : 190

Euastrum subcyclopicum var. elongatum Thérézien (1985: 82) ( Figs 35–39 )

Cell dimensions: length 52–57 μm, breadth 23–25,5 μm, apical lobe 21 μm, isthmus 7–8 μm

Habitat characteristics: Dam, periphyton; water temperature 21ºC, pH 7.8, conductivity 10 μS. cm-1, dissolved oxygen 9.2 mg.L- 1.

Material examined: HUEFS 244149.

Notes: Euastrum subcyclopicum var. elongatum has as its main characteristics long spines divergent in the angles of the apical lobe, a large scrobicle in the mid-region of the semicell, and a granule in the supraisthmal region. Large populations of this taxon were observed in the sample studied, although no relevant morphological variations were observed. Regarding its geographic distribution, this variety was only known from its type locality, French Guiana ( Thérézien 1985), which makes the present record new for Brazil. It is likely to be endemic to South America, as well as other morphologically similar taxa, such as Euastrum pirassunungae Borge (1918: 58) .

Figures

FIGURES 28–50. Euastrum piataense (28–34): LM (28–31), SEM (33,34), ventral view (28–30, 33), lateral view (31,34) apical view (32); Euastrum subcyclopicum var. elongatum (35–39): LM (35–38), SEM (39), ventral view (35–36, 39), lateral view (37), apical view (38); Euastrum bicudoi (40–42): ventral view (40), lateral view (41), apical view (42); Euastrum subtrilobulatum var. laeve (Figs 43–46): ventral view (43,44), lateral view (45), apical view (46); Micrasterias arcuata var. perforata (47–50): LM (47–49), SEM (50), zygospore (49). Scale bar 10 μm.