A New Species of Centrohelid Heliozoan Acanthocystis amura n. sp. Isolated From Two Remote Locations in Russia

Abstract

A new species of centrohelid heliozoan Acanthocystis amura from the Amur River, the Far East of Russia was studied with light- and electron microscopy. Acanthocystis amura has simple oval plate scales (1.2-2.6 × 1.0-1.8 μm) with an axial thickening and a thin border as well as two types of spine scales. The spine scales of type 1 were 1.3-4.8 μm long and had four small hooks on their tips. The spine scales of type 2 were shorter, 1.0-3.6 μm long and had four teeth at the distal end. The morphology of A. amura resembles that of Acanthocystis quadrifurca. They both have similar spine scales but their plate scales are completely different. Acanthocystis valdiviense differs from the new species in absence of hook-bearing scales. Molecular phylogeny based on 18S rDNA consistently placed A. amura into Acanthocystis nichollsi/Acanthocystis costata clade, but relationships between those three species were not resolved. Morphology of another centrohelid strain from another location (the South Urals) has been compared with that of the original strain and few minor differences in size characteristics of the scales have been revealed.

Centrohelid Heliozoans (Centroplasthelida Febvre-Chevalier et Febvre, 1984) from Different Types of Freshwater Bodies in the Middle Russian Forest-steppe

“…The current centrohelid system (Zlatogursky et al 2018, Adl et al 2019) is used. The data on distribution of cen- Zlatogursky et al, 2017 (Fig. 2A-E) Description: Spine scale consists of a straight cylindrical shaft and a circular flattened base.…”

“…Many of them are rarely observed and little is known about their morphological variability and ecological distribution. Despite this, the descriptions of a new species are appearing constantly (Cavalier-Smith and von der Heyden 2007, Leonov 2010b, Tikhonenkov and Mylnikov 2011, Zlatogursky 2015, Zlatogursky et al 2017. The diversity of the centrohelids has been studied unevenly, with some regions explored more intensively than others (Nicholls 1983, Croome 1986, Dürrschmidt 1987a, Leonov and Plotnikov 2009, Kosolapova and Mylnikov 2015.…”

Pinjata ruminata gen. et sp. n.—A New Member of Centrohelid Family Yogsothothidae (Haptista: Centroplasthelida) from the Brackish River

“…The sample from the Tuzlukkol’ River was incubated in a Petri dish at + 20–24 °C under room light for a week and heliozoans grew without isolation in pure culture as described in Zlatogursky et al. ().…”

Multiple Euryhaline Lineages of Centrohelids (Haptista: Centroplasthelida) in Inland Saline Waters Revealed with Metabarcoding

“…; Zlatogursky , , , ; Zlatogursky et al. ). Metabarcoding (high‐throughput sequencing (HTS) of environmental DNA barcodes) is commonly used for describing a global taxonomic diversity of protists (Lejzerowicz et al.…”

“…Sequencing of 18S rDNA amplicons from the total DNA of environmental samples has revealed a considerable diversity of centrohelids, and it was suggested that over 90% of centrohelid species probably remain undescribed (Cavalier-Smith and von der Heyden 2007). New species and novel sequences of centrohelids have been revealed in almost every environmental screening focused on this group (Cavalier-Smith and Chao 2012;Cavalier-Smith and von der Heyden 2007;Gerasimova and Plotnikov 2016;Shɨshkin et al 2018;Zlatogursky 2010Zlatogursky , 2012Zlatogursky , 2014Zlatogursky , 2016Zlatogursky et al 2017). Metabarcoding (high-throughput sequencing (HTS) of environmental DNA barcodes) is commonly used for describing a global taxonomic diversity of protists (Lejzerowicz et al 2015;Pawlowski et al 2016Pawlowski et al , 2018Stoeck et al 2009Stoeck et al , 2018 with the vast majority of studies based on the 18S rDNA sequencing due to the popularity of the 18S rDNA-derived universal eukaryotic primers (Hadziavdic et al 2014).…”