Diversity of Silica-Scaled Chrysophytes in the Steppe Zone of the Southern Urals with a Description of a New Species from the Genus Mallomonas.

This paper is devoted to the study of the flora of silica-scaled chrysophytes in water bodies of the steppe zone of the Southern Urals (Russia). Twenty-four taxa were identified via scanning and transmission electron microscopy, twenty of which are representatives of the genus Mallomonas Perty, while four are species of the genus Synura Ehrenberg. In the course of the study, a species new to science from the genus Mallomonas, M. baturinae sp. nov., was described. This species belongs to the section Papillosae. The stomatocyst of M. doignonii was described. For the first time in Russia and for the third time since description, M. phasma and M. solea-ferrea var. irregularis were reported in the studied area. Here, their extended description is provided with illustrations of their scales in detail. Some rare taxa for the flora of Russia have been identified: M. doignonii, M. pillula f. exannulata, and M. pillula f. valdiviana. One taxon of the genus Mallomonas has not been identified to a species level and is probably a taxon new to science.

On stomatocysts of Paraphysomonas caelifrica (Stramenopiles, Paraphysomonadida).

Stomatocysts of the rare heterotrophic chrysophyte, Paraphysomonas caelifrica, were discovered from a shallow ephemeral pond Tavolgasai ("Orenburgskiy" State Nature Reserve, Orenburg Region, Russia). Morphology of stomatocysts was studied using scanning electron microscopy. Stomatocysts of P. caelifrica are spherical and smooth with a cylindrical collar surrounding the regular pore. So, they do not belong to the stomatocyst 1 Duff and Smol as previously thought. The description of a new stomatocyst morphotype is provided.