The Genus Frustulia in Tierra del Fuego peatbogs (Argentina)

VALERIA CASA; GABRIELA MATALONI; BART VAN DE VIJVER

Praga

Congreso; 11th Central European Diatom (11th CED) meeting; 2017

Faculty of Science Charles-University

Peatlands are vulnerable ecosystems and at present only studied in detail in the northernhemisphere. Their proper functioning is crucial for the biotic communities that thrive in theseenvironments. Data on peatlands in the southern hemisphere are, however, scarce and apart fromdata on the sub-Antarctic islands, almost nothing is known from the diatom flora in this habitat. Thepresent study describes the diatom flora from two peatbogs (Rancho Hambre and Andorra Valley) inTierra del Fuego, Patagonia, Argentina.Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, acrossthe Strait of Magellan. It encompasses a vast area of pristine peatlands, making up almost 95% of allpeatbogs in Argentina. The pools and peatbogs in the sampled peatlands are characterized by lowconductivity, low pH and low nutrient values. The vegetation is mainly dominated by Sphagnummagellanicum.During the survey of the freshwater diatom flora of these Tierra del Fuego peatbogs, a diversediatom flora was observed, composed of several Eunotia, Brachysira and Pinnularia taxa. A total ofeight Frustulia taxa was observed in the samples. Two of them had been previously described: F.vulgaris and F. kosmolliana. Comparison with the type material of Frustulia (Navicula) crassinerviaconfirmed the conspecificity with one of the unknown populations. Five taxa could not be identifiedusing the currently available literature. Based on extensive analysis of light and scanning electronmicroscopy observations, and after comparison with almost all previously described Frustulia taxaworldwide, it is clear that these taxa are new for science.The poster illustrates several, probably new, taxa using light and scanning electron microscopyobservations and compares them to previously described taxa.