Netrium digitus (Brébisson ex Ralfs) Itzigsohn & Rothe

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 : 69

Netrium digitus (Brébisson ex Ralfs) Itzigsohn & Rothe in Rabenhorst (1856:508) ( Figs 93–96 )

Cell dimensions: 160–260 μm length, 35–50 μm width

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 224672), 11-IX-2015, G. J. P. Ramos et al. s/n ( HUEFS 224697), 20-XI-2015, G. J. P. Ramos et al. s/n ( HUEFS 224718).

Habitat: bromeliad tanks ( Alcantarea nahoumii ); T 27.4 (± 2.8 ºC). pH 5.9 (± 0.4). C 0.23 (± 0.16 mS. cm-1). TDS 0.13 (± 0.11 ppt). DO 8.3 (± 4.4 mg.L- 1).

Notes, Netrium digitus was the desmid most parasitized by chytrid fungi in bromeliads at Serra da Jiboia, with 2–4 zoosporangia commonly found inside the cell. This pattern was also recorded in specimens from Holland ( Coesel & Meesters 2007), which suggests that this relationship may be specific and more widely distributed than previously thought.

Netrium digitus was one of the most predominant desmids, showing large populations in some bromeliads, often forming floating masses visible to the naked eye in bromeliad tanks. This is the first record of genus Netrium in a phytotelmata habitat.

Figures

FIGURES 93–112. Netrium digitus: LM (93–95); SEM (96); Pleurotaenium trabecula: LM (97–98); SEM (99–100); Staurastrum pseudosebaldi var. compactum LM (101–104), ventral view (101–103), apical view (104); Staurastrum pseudoteliferum sp. nov.: LM (105–106, 109–110); SEM (107–108), ventral view (105–107), apical view (108–110); Xanthidium mamillosum var. borgei: LM (111– 112); ventral view (111), apical view (112). Scale bar 50 μm (93–95), 60 μm (92–94), 40 μm (97), 30 μm (104–105, 111–112), 20 μm (96, 99–100), 10 μm (98, 101–108)