New and noteworthy chrysophycean stomatocysts from the Steppe zone of South Urals (Russia) with comments on the morphological variability.

Abstract

Morphology of seven chrysophycean stomatocysts was studied using scanning electron microscopy. All stomatocysts were recorded from the shallow lakes located in the Steppe zone of South Urals. Four morphotypes (stomatocyst 373 Taylor et Smol, stomatocyst 68 Van de Vijver et Beyens, stomatocyst 99 Pang et Wang and stomatocyst 101 Pang et Wang Forma B) are rare and reported for the first time in Russia. New observations on the formation of the cyst ornamentation allowed us to amend the descriptions of two morphotypes. Three stomatocysts are described as new to science. Morphological variability of all seven morphotypes are illustrated and discussed.