Desmidium longatum Wolle, Desmids of the United States. 26, pl. 49, fig. 6. 1884.

Gymnozyga longata (Wolle) Nordstedt in Wittrock & Nordstedt, Algae Exsiccatae 15: nº 803. 1886.

(Figs. 10 A-C)

Cell 2.3 greater in length than width, 65-83 × 28-39 μm, 14-20 μm broad at the apex and 22-31 μm broad at the isthmus. Semicells pyramidal-truncate; straight apical margins; parallel lateral margins, slightly divergent to the apex; broad apex; broad to moderate truncated median constriction; conspicuous basal inflation on both sides of the isthmus; open to linear median sinus; hyaline cell wall; axial chloroplast.

Material examined: BRAZIL, AMAPÁ, Macapá, Curralinho Lake, 02.VI.2007, C.B. Araújo (SP469217), 03.VII.2007, C.B. Araújo (SP469218), 15.IV.2008, C.B. Araújo (SP469226), 15.VII.2008, C.B. Araújo (SP469228) .

Comments: the present species resembles Bambusina brebissonii Kützing or Bambusina borreri (Ralfs) Cleve. However, D. longatum Wolle is different, as it presents twisted pseudofilaments, elliptic cells in an apical view, and cells larger than B. brebissonii . The specimens identified here are larger than the ones from North America, registered in Croasdale et al. (1983: 35-40 × 25-28 µm).

Distribution in Brazil: first record of this species in Brazil.