Spondylosium rectangulare (Wolle) West & West var. rectangulare

Araújo, Camila Barbosa de, Bicudo, Carlos Eduardo de Mattos, Takiyama, Luís Roberto & Melo, Sérgio de, 2020, Pseudofilamentous desmids (Zygnematophyceae) from an Amazonian floodplain lake (Macapá, AP, Brazil), Iheringia, Série Botânica (e 2020010) 75, pp. 1-14 : 10

Spondylosium rectangulare (Wolle) West & West var. rectangulare , Transactions of the Linnean Society, London: ser. 2, 5(5): 231, pl. 12, fig. 13-14. 1896.

Sphaerozosma rectangulare Wolle , Desmids of the United States. 31, pl. 49, fig. 9. 1884.

( Fig. 22 )

Cell 2.7 times broader than long, 20 × 55-92 µm, and 14- 24 μm broad at the isthmus. Semicells oblong-rectangular; apical margin straight, convex at the end; each angle ending in 1 short spine; median constriction deep; median sinus open; cell wall hyaline; chloroplast axial.

Material examined: BRAZIL, AMAPÁ, Macapá, Curralinho Lake , 02.VI.2007, C.B. Araújo (SP469217), 03.VII.2007, C.B. Araújo (SP469218), 12.II.2008, C.B. Araújo (SP469224), 15.IV.2008, C.B. Araújo (SP469226), 15.VII.2008, C.B. Araújo (SP469228) .

Comments: the presence of this species was documented in Brazil by Grönblad (1945), based on material collected in the state of Pará. Morphological variation was detected in this study when considering different cells of the same pseudofilament. The sinus opening varied as it was either broadly open and acute or open next to the isthmus or closed at the distal region due to the convergence of the semicell spines.

Distribution in Brazil: Goiás (Förster 1964); Pará ( Grönblad 1945, Förster 1969).

Figures

Figs. 16-23. Pseudofilamentous desmids of Curralinho Lake, Macapá,Amapá, Brazil. 16 A-B. Hyalotheca dissiliens var. dissiliens. A. fungi in the cell wall of the algae, B. detailed cells; 17 A-B. H. javanica. A. detailed pseudofilament, B. detailed cells; 18. Mateola curvata; 19 A-B. Phymatodocis nordstedtiana var. nordstedtiana f. minor. A. pseudofilament frontal view, B. pseudofilament lateral view; 20. Spondylosium desmidiiforme; 21. S. pulchrum var. pulchrum; 22. S. rectangulare var. rectangulare; 23 A-B. S. rectangulare var. goyazense, detailed cells and pseudofilaments. Scale bars = 10 µm.