The Morphology, Ultrastructure and Molecular Phylogeny of a New Freshwater Heterolobose Amoeba Parafumarolamoeba stagnalis n. sp. (Vahlkampfiidae; Heterolobosea)

Anastasia Borodina,Denis Tikhonenkov,Alexander Mylnikov,Jan Janouškovec,Patrick Keeling

doi:10.3390/d13090433

Abstract

Heterolobose amoebae are important members of marine, freshwater, and soil microbial communities, but their diversity remains under-explored. We studied the diversity of Vahlkampfiidae to improve our understanding of heterolobosean relationships and their representation in aquatic benthos. Using light and electron microscopy, and molecular phylogenies based on the SSU rRNA and ITS loci, we describe the fine morphology and evolutionary relationships of a new heterolobosean Parafumarolamoeba stagnalis n. sp. from a small pond in European Russia. Cells of P. stagnalis possess a clearly distinguishable anterior hyaline pseudopodium, eruptive movement, several thin and sometimes branched uroidal filaments, spherical cysts without pores and plugs, and mitochondria that have discoid cristae and are surrounded by cisternae of the endoplasmic reticulum. The genus Parafumarolamoeba has so far included a single species, Parafumarolamoeba alta from high-altitude soil in Tibet, which is morphologically distinct from P. stagnalis. Taxonomic description for a new Parafumarolamoeba species is therefore provided.

Highlights

Heterolobose amoebae are important members of marine, freshwater, and soil microbial communities, but their diversity remains under-explored
The genus Naegleria is the most well studied of them: N. fowleri is a deadly human parasite [1] and N. gruberi is a model for the development of the flagellar apparatus [2]
The cells possess a distinct anterior hyaline pseudopodium, which is usually solitary but can occur as a pair of competing pseudopodia formed by eruptive movement (Figure 1A–C; Video S1)

Summary

Introduction

Heterolobose amoebae are important members of marine, freshwater, and soil microbial communities, but their diversity remains under-explored. We studied the diversity of Vahlkampfiidae to improve our understanding of heterolobosean relationships and their representation in aquatic benthos. Parafumarolamoeba has so far included a single species, Parafumarolamoeba alta from high-altitude soil in Tibet, which is morphologically distinct from P. stagnalis. 1. Introduction with regard to jurisdictional claims in Heterolobosea Page and Blanton 1985 is a relatively small group of protists belonging to Discoba and combining heterotrophic amoeboflagellates, amoebae, flagellates and some slime molds (Acrasidae). Other heteroloboseans have been studied to a much lesser extent, despite their wide environmental presence and morphological diversity. Members of the family Vahlkampfiidae contribute significantly to the diversity and abundance of amoebas in a wide variety of aquatic and terrestrial habitats [3,4,5]. Vahlkampfia was initially distinguished by the lack of a flagellate stage and pores in the cyst wall [6]

Methods

Results

Conclusion