Cosmarium pseudopyramidatum var. pseudopyramidatum P. Lundell

Cosmarium pseudopyramidatum var. pseudopyramidatum P. Lundell

( Fig. 2L View FIG )

Nova Acta Regiae Societatis Scientiarum Upsaliensis, serie 3, 8 (2): 41 ( Lundell 1871). — Euastrum pseudopyramidatum (P. Lundell) F. Gay, Essai d ’ une monographie locale des Conjugées: 60 ( Gay 1884).

Cosmarium pyramidatum var. minus Reinsch, Abhandlungen der Naturhistorischen Gesellschaft zu Nürnberg 3 (2): 152 ( Reinsch (1866).

Cosmarium pseudopyramidatum f. minus Raciborski, Rozprawy Wydzialu Matematyczno-Przyrodniczego Akademii Umiejetnosci 2 (2): 364 ( Raciborski 1892).

DISTRIBUTION. — Cosmopolitan. Amazon Basin: Thomasson (1971), Souza de et al. (2007); Cadima (2013). Western Amazonia (lowlands): Araujo (2003); Díaz-Olarte & Duque (2009).

DESCRIPTION

Cells 79.1-80.0 µm long, 46.8-47.2 µm wide, isthmus 16.6-16.9 µm; cells 1.7 times longer than wide. Cells have an oval shape with a profoundly constricted central section, median sinus linear, narrow, dilated at the apex; semicell pyramidal-truncated, with a shallow notch on the median part of the apex; basal angles rounded, lateral margins slightly convex to almost straight, cell wall hyaline, finely punctate; axial chloroplast; one pyrenoid.

REMARKS

Our specimens are morphologically similar but larger to the original description of Lundell (1871) and those reported by West & West (1905), Tell & Couté (1993), Oliveira de et al. (2010), and Aquino et al. (2016).