Spomdylosium rectangulare (Wolle) West & West var. goyazense Förster

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 : 11

Spomdylosium rectangulare (Wolle) West & West var. goyazense Förster , Hydrobiologia 23 (3-4): 434, pl. 35, fig. 15-17, pl. 37, fig. 11-12, pl. 50, fig. 19-20. 1964.

( Figs. 23 A-B)

Cell 2.7 times broader than long, 27 × 92-96 μm and 24 μm broad at the isthmus. Semicells oblong-rectangular; straight apical margin that were sometimes convex at the terminal extension; each angle ended at a robust spine; there was 1 spine in the mid region of the lateral margins; deep median constriction; linear to open median sinus; axial chloroplast.

Material examined: BRAZIL, AMAPÁ, Macapá, Curralinho Lake , 02.VI.2007, C.B. Araújo (SP469217), 03.VII.2007, C.B. Araújo (SP469218), 13.V.2008, C.B. Araújo (SP469227) .

Comments: the present variation differs from the typical species, as it is greater in size and has the apical margin of straight semicells. It also has a slight incision at the mid region and rounded lateral margins with four overlapping divergent spines or tubers at the angular ends. Förster (1964) described this variety from material collected from the Fêmeas River in Porta Azul in Goiás state. Scott et al. (1965) proposed f. maius Scott & Croasdale from material collected in the state of Pará, due to its broader width and an apical indentation when compared to S. rectangulare (Wolle) West & West. The illustration in Scott et al. (1965) showed measurements and morphology in agreement with the ones registered in Förster (1964) as S. rectangulare var. goyazense Förster. Due to the above difficulty in differing specimens cited by the latter authors, and considering that the specimens in the present study showed morphological variation even in the same pseudofilament, it was decided to consider both taxa as synonymous (heterotypic or taxonomic synonyms).

Distribution in Brazil: Goiás (Förster 1964, Nogueira et al. 2016); Pará ( Scott et al. 1965).

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.