Docidium baculum Brébisson ex Ralfs (1848: 158)

Ramos, Geraldo José Peixoto, Bicudo, Carlos Eduardo De Mattos & Moura, Carlos Wallace Do Nascimento, 2018, Some new, rare and interesting desmids from bromeliad phytotelmata in Brazil, Phytotaxa 346 (1), pp. 59-77 : 67

Docidium baculum Brébisson ex Ralfs (1848: 158) ( Figs 49–51 )

Cell dimensions: 185–200 μm length, 9.5–10 μm width, 7–8 μm isthmus.

Material examined: BRAZIL, Bahia, Santa Teresinha, Serra da Jiboia. 14-I-2015, G. J. P. Ramos et al. s/n ( HUEFS 224657), 18-VII-2015, G. J. P. Ramos et al. s/n ( HUEFS 224676), 11-IX-2015, G. J. P. Ramos et al. s/n ( HUEFS 224702), 20-XI-2015, G. J. P. Ramos et al. s/n ( HUEFS 224718).

Habitat: bromeliad tanks ( Alcantarea nahoumii ); T 26.9 (± 3.2 ºC). pH 5.9 (± 0.6). C 0.23 (± 0.17 mS. cm-1). TDS 0.13 (± 0.11 ppt). DO 7.2 (± 2.7 mg.L- 1).

Notes: This species is relatively easy to identify, as the base of the semicell is ornamented by a set of plications. Nonetheless, certain care was needed in the analysis of the populations from Serra da Jiboia because that species was often found in the same samples as Pleurotaenium trabecula . Although the latter species differs by having a semicell base without plications and larger cell dimensions, the populations of those taxa, when occurring together, give the false impression of morphological variation in a single species. This is the first report of the genus Docidium occurring in a phytotelmata habitat.

Figures

FIGURES 49–72. Docidium baculum: LM (49–50); SEM (51), ventral view (49) and the isthmus details (50–51); Euastrum quadriceps: LM (52–56); SEM (57), lateral view (52), ventral view (53, 57), apical view (54–56); Euastrum luetkemuelleri var. carniolicum: LM (58– 65) SEM (66–67), ventral view (58–60, 66), diagonal view (67), lateral view (61), apical view (62–63), zygospores (64–65); Actinotaenium mooreanum: LM (68–69, 71–72) SEM (70), ventral view (68–670) and zygospores (71–72). Scale bars 10 μm (Figs 42–59, 62–66), 5 μm (Figs 60–61). Scale bar 10 μm (49–65, 68–72), 5 μm (66–67).