Spondylosium pulchrum Bailey var. pulchrum

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 pulchrum Bailey var. pulchrum in Ralfs, British Desmidieae. 209, pl. 35, fig. 3. 1848.

( Fig. 21 )

Cell 1.7 times broader than long, 38 × 65 μm and 19 μm broad at the isthmus. Semicells more or less transversally elliptical; rectangular lateral margins; broadly rounded angles and were slightly convex along its extension; deep median constriction; open median sinus, sometimes sublinear or clearly linear close to the isthmus; hyaline cell wall; 4-lobed chloroplast.

Material examined: BRAZIL, AMAPÁ, Macapá, Curralinho Lake , 13.V.2008, C.B. Araújo (SP469227), 15.VII.2008, C.B. Araújo (SP469228) .

Comments: the study of the material collected at the Taperinha farm, Santarém, Pará state, allowed Grönblad (1945) to provide the most comprehensive documentation of this species in Brazil. This author referred to var. brasilienses Nordstedt and illustrated the zygospore and two more individual specimens: one of them with a closed sinus and the other one with an open sinus. According to Bicudo & Samanez (2016), this species was represented by two distinct morphological populations, one with elliptical semicells and sinus open, and the other one with oblong semicells and sinus closed or almost linear throughout. Nevertheless, both morphologies can be observed in different cells of one and the same pseudofilament.

Distribution in Brazil: Bahia ( Bicudo & Martins 1989, Oliveira et al. 2010); Pará ( Grönblad 1945, Scott et al. 1965); Paraná (Bittencourt-Oliveira 1993b, Biolo et al. 2008); Rio de Janeiro ( Sophia 1987); São Paulo ( Bicudo & Samanez 1984, 2016, Taniguchi et al. 1998); Federal District ( Leite & Senna 1992).

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.