Gomphonema brasiliense ssp. pacificum Moser, Lange-Bertalot & Metzeltin,, 1844

Ruwer, Daiane Trevisan & Rodrigues, Liliana, 2021, Sediment diatoms from Upper Paraná River floodplAiN lAKeS: New recordS, Iheringia, Série Botânica (e 2021012) 76, pp. 1-16 : 10

Gomphonema brasiliense ssp. pacificum Moser, Lange-Bertalot & Metzeltin,

Biblioth. Diatomol., 38: 185, pl. 50, figs. 1-6. 1998.

( Figs. 126-128 )

Valves heteropolar, narrowly lanceolate. Apical and basal ends attenuate-rounded. Axial area wide and lanceolate, central area indistinct. Raphe straight, with proximal ends, slightly dilated to pores. Transapical striae short, parallel to radiate toward the ends. Stigma absent. Length: 21-31μm; width: 3.5-5.3 μm; striae 13-14 in 10 μm. Gomphonema brasiliense ssp. pacificum resembles G. brasiliense concerning shape valve and the short striae. G. brasiliense ssp. pacificum differ morphologically by the presence of ends more attenuate and lower valve dimensions, mainly the width values ( Metzeltin et al. 2005). This taxon was registered in Brazilian studies of Marquardt & Bicudo (2014) and Medeiros et al. (2018).

Material examined: BRAZIL, MATO GROSSO DO SUL: Taquaruçú, Patos Lake , 23.III.2018, sediment, D.T. Ruwer (Nupélia UEM - 18099-106 , 18109 , 18113-122 ) .

Occurrence: first citation for Upper Paraná River floodplain.

Figures

Figure 86-152. Sediment diatoms from subtropical floodplain lakes (LM). 86-94. Achnanthidium exiguum; 95-97. Achnanthidium minutissimum; 98-101. Planothidium bagualensis; 102-105. Placoneis ovillus; 106-109. Cocconeis sp. 1; 110-113. Planothidium dubium; 114-116. Encyonema silesiacum; 117-120. Gomphonema angustatum; 121-125. Gomphonema brasiliense; 126-128. Gomphonema brasiliense spp. pacificum; 129-132. Gomphonema lagenula; 133-136. Gomphonema sp. 1; 137-139. Brachysira neoexilis; 140-152. Naviculadicta sp.1. (Scale bar: 10 μm).