Staurodesmus triangularis (Lagerh.) Teiling

Staurodesmus triangularis (Lagerh.) Teiling

( Fig. 7H, I View FIG )

Botanica Notiser 1948: 62 ( Teiling 1948). — Arthrodesmus triangularis Lagerheim, Öfversigt af Kongliga Vetenskaps-Akademiens Förhandlingar 42 (7): 244 ( Lagerheim 1886).

Staurastrum dejectum subsp. tellamii West & G. S.West , Journal of the Royal Microscopical Society 1894: 10 ( West & West 1894). — Arthrodesmus triangularis f. triquetra West & G. S. West , A monograph of the British Desmidiaceae. IV: 99 ( West & West 1912). — Staurastrum megacanthum var. orientale A. M. Scott & Prescott, Hydrobiologia 17 (1/2): 98 ( Scott & Prescott 1961). — Staurodesmus orientalis (A. M. Scott & Prescott) Coesel, Cryptogamie, Algologie 14 (2-3): 110 ( Coesel 1993).

DISTRIBUTION. — Cosmopolitan. Amazon Basin: Förster (1969, 1974); Thomasson (1971); Uherkovich & Schmidt (1974); Uherkovich (1976, 1981); Uherkovich & Rai (1979); Sophia & Huszar (1996); Huszar & Reynolds (1997); Melo et al. (2005); Souza de et al. (2007); Melo & Souza de (2009); Souza de & Melo (2011); Cadima (2013). Western Amazonia (lowlands): Díaz-Olarte & Duque (2009).

DESCRIPTION

Cells 25.2-25.8 µm long, 18.0-20.6 µm wide; isthmus 5.7-6.0 µm; cells 1.3-1.4 longer than wide. Cells with a deep, wide open sinus. The isthmus is usually elongated; the body of the semicell over the isthmus is triangular. The apex is slightly elevated by a median depression. The apical angles are rounded, and they have long spines that can be parallel, divergent, or convergent (mainly convergent in our specimens).

REMARKS

Our specimens coincided morphologically with descriptions and drawings for the Brazilian Amazon specimens of Staurodesmus triangularis ( Förster 1969, 1974; Sophia & Huszar 1996). This taxon has also been considered as highly polymorphic ( Bicudo & Azevedo 1977).