Additions to chrysophycean stomatocyst flora from South Urals shallow lake including descriptions of three new morphotypes

Abstract

In this study we observed 17 additional morphotypes of chrysophycean stomatocysts from the shallow lake Zhurmankol which is located in a protected zone of South Urals steppes (Russia). Including our new records, the number of known chrysophycean stomatocysts from the Lake Zhurmankol increased to 32 morphotypes. Three morphotypes are described as new to science. Their similarity and difference from previously described morphotypes are discussed. While the biological affinity of two new morphotypes remains unknown, the third stomatocyst was produced by a heterotrophic chrysophyte species, Paraphysomonas bandaiensis. Critical analysis of the published micrographs of P. bandaiensis siliceous scales from Russia revealed that they belong to another, yet undescribed, taxon (or taxa). So, our report on P. bandaiensis is the first confirmed record of this species in Russia.

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

“…Previously, 15 taxa of Mallomonas and 13 taxa of Synura were recorded in diverse water bodies in the montane-forest zone of the eastern foothills of the Southern Urals and the steppe zone of the Southern Urals using electron microscopy [14,38,[50][51][52][53][54]68]. The results obtained in this study made it possible to supplement this list with 13 new taxa, one of which is described as new to science and two (M. phasma, M. solea-ferrea var.…”

“…During studies of the flora of silica-scaled chrysophytes in the water bodies of the steppe zone of the Southern Urals, several interesting stomatocysts were found [68][69][70]. Stomatocysts are the endogenous siliceous resting stage of the chrysophyte life cycle.…”

“…Numerous studies of chrysophytes from different regions, such as North America [58][59][60], Europe [61,62], Asia [63][64][65][66][67], and Russia [23][24][25]29], have shown that water bodies of the protected areas have a rich and distinctive flora and often include species new to science. The first studies of the protected natural areas of the Southern Urals identified 32 morphotypes of chrysophycean stomatocysts in the flora of Lake Zhurmankol, located on the territory of the Ashchisai Steppe site of the "Orenburgskii" State Nature Reserve, which indicates a wide variety of golden algae in this water body [68][69][70]. In addition, Mallomonas rasilis Dürrschmidt, a new species of chrysophytes for the flora of Russia, was also recorded in Lake Zhurmankol [14].…”

On stomatocysts of Paraphysomonas caelifrica (Stramenopiles, Paraphysomonadida)

“…Like other chrysophytes, paraphysomonadids can produce siliceous resting stages called stomatocysts which usually have species-specific morphology. Unfortunately, the stomatocyst ultrastructure is known only for a few Paraphysomonas sensu lato taxa (Coradeghini & Vigna, 2008;Ignatenko et al, 2022;Kling & Findlay, 2001;Takahashi, 1981Takahashi, , 1987. The aim of this article is to describe stomatocysts produced by Paraphysomonas caelifrica.…”