New and interesting species of the genusMuelleria(Bacillariophyta) from the Antarctic region and South Africa

Abstract

During a survey of the terrestrial diatom flora of some sub-Antarctic islands in the southern Indian and Atlantic Oceans and of the Antarctic continent, more than 15 taxa belonging to the genus Muelleria were observed. Nine of these taxa are described as new species using light and scanning electron microscopy. Comments are made on their systematic position and how they are distinguished from other species in the genus. Additionally, two previously unrecognized taxa within the genus were discovered in samples from South Africa. One of these, Muelleria taylorii Van de Vijver & Cocquyt sp. nov., is new to science; the other, Muelleria vandermerwei (Cholnoky) Van de Vijver & Cocquyt nov. comb., had been included in the genus Diploneis. The large number of new Muelleria taxa on the (sub)-Antarctic locations is not surprising. Species in Muelleria occur rarely in collections; in many habitats, it is unusual to find more than 1-2 valves in any slide preparation. As a result, records are scarce. The practice of ''force-fitting'' (shoehorning) specimens into descriptions from common taxonomic keys (and species drift) results in European species, such as M. gibbula and M. linearis, being applied to Antarctic forms in ecological studies. Finally, the typical terrestrial habitats of soils, mosses and ephemeral water bodies of most of these taxa have been poorly studied in the past.

The genus Nitzschia on the South Shetland Islands and James Ross Island

“…and Stauroneis eHrenb. were observed and described (e.g., van de vijver & mataloni 2008;Kopalová et al 2011;van de vijver et al 2010, 2011Zidarova et al 2010Zidarova et al , 2012Zidarova et al , 2014. These studies led to the overall conclusion that not all Maritime Antarctic islands share a similar flora and while the diversity of this flora is limited compared to more temperate or tropical localities, many of the newly discovered taxa are endemic to the region and not cosmopolitan as was previously reported (van de vijver et al 2005;Kopalová et al 2014).…”

A brackish diatom, Pseudofrustulia lancea gen. et sp. nov. (Bacillariophyceae), from the Pacific coast of Oregon (USA)

“…Pseudofrustulia is distinguished from Frustulia, Frickea Heiden (1906: 264), Amphipleura Kützing (1844: 103), Envekadea Van de Vijver et al in Gligora et al (2009: 136), and Muelleria Frenguelli (1945: 172) mainly by the structure of the axial ribs along the raphe, differences in raphe features, the helictoglossa, and the positions of the areolae on the inner side of the valve. Previous studies also have used these morphological features to distinguish taxa within the Amphipleuraceae (Round et al 1990, Spaulding & Stoermer 1997, Gligora et al 2009, Van de Vijver et al 2010. Girdle bands may also be important in differentiating Pseudofrustulia from related taxa (Ross & Sims 1978, Round et al 1990, Spaulding & Stoermer 1997, Gligora et al 2009, Van de Vijver et al 2010.…”

“…Previous studies also have used these morphological features to distinguish taxa within the Amphipleuraceae (Round et al 1990, Spaulding & Stoermer 1997, Gligora et al 2009, Van de Vijver et al 2010. Girdle bands may also be important in differentiating Pseudofrustulia from related taxa (Ross & Sims 1978, Round et al 1990, Spaulding & Stoermer 1997, Gligora et al 2009, Van de Vijver et al 2010. Pseudofrustulia is considered to be a monotypic genus at present.…”

“…Some typical species of Frustulia (Graeff et al 2012) have features similar to those of Pseudofrustulia in an internal valve view, but the internal ribs are fused with a central nodule and the helictoglossae. Frickea and Muelleria also have internal ribs, but their ribs are separated from the central nodule and the helictoglossae (Round et al 1990, Spaulding & Stoermer 1997, Spaulding et al 1999, Van de Vijver et al 2010, Bahls 2014 (Fig. 24).…”

“…Similarly, Amphipleura has short but simple raphe features in both external and internal views (Cox 1975, Round et al 1990). In contrast, Envekadea and Muelleria are characterized by oppositely deflected or unilaterally deflected and branched raphes in external view, respectively (Van de Vijver et al 2010, Lee et al 2013 (Fig. 24).…”