Centrohelid Heliozoans from Freshwater Habitats of Different Types of South Patagonia and Tierra del Fuego, Chile

The species composition of centrohelid heliozoans from freshwater habitats of different types (sphagnum bog, temporary and permanent water bodies and streams) of Southern Chile has been studied. Fourteen species ( Acanthocystis nichollsi , A. pectinata , A. penardi , Pseudoraphidiophrys discoidea , P. formosa , P. veliformis , Raphidiophrys ovalis , Choanocystis perpusilla , Pterocystis foliacea truncata , P. pyriformis , P. quadrata , Raineriophrys erinaceoides , R. fortesca , and R. pteromorphos ) are observed. Two species ( Acanthocystis nichollsi and Pterocystis quadrata ) are recorded in Chile for the first time. Most of these species are recorded in Southern Chile for the first time. Electron microscopy is used to investigate the external morphology of scales, having important diagnostic value. Morphological descriptions and micrographs of studied scales amplify the concept of intraspecies variability and supplement the diagnosis of species.