Survey on diversity of marine/saline anaerobic Heterolobosea (Excavata: Discoba) with description of seven new species

Abstract

Diversity of the anaerobic Heterolobosea (Excavata: Discoba) is only poorly understood, especially in marine environments. We have isolated and cultured 16 strains of anaerobic heteroloboseid amoebae and flagellates from brackish, marine and saline anoxic habitats worldwide. Phylogenetic analyses of SSU rDNA sequences and light-microscopic observations showed that all the strains belong to the family Psalteriomonadidae, the main anaerobic lineage of Heterolobosea, and that they represent eight species from the genera Monopylocystis, Harpagon and Pseudoharpagon. Seven species are newly isolated and described here as Monopylocystis minor n. sp., Monopylocystis robusta n. sp., Monopylocystis elegans n. sp., Monopylocystis disparata n. sp., Harpagon salinus n. sp., Pseudoharpagon longus n. sp. and Pseudoharpagon tertius n. sp. Amoebae, cysts and the ultrastructure of the genus Pseudoharpagon are presented for the first time.

Neovahlkampfia nana n. sp. Reinforcing an Underrepresented Subclade of Tetramitia, Heterolobosea

“…The enigmatic electron‐dense structures that were found in the cytoplasm of the UD12 cells, along with mitochondria with well defined discoid cristae, had no internal membranes and thus looked similar both to the acristate organelles described in anaerobic heteroloboseans (Pánek et al. ) and to some inclusions documented by Fawcett (). Comparison of dozens of ultrathin sections through the globular UD12 cells revealed certain signs of transformation of the organelle in question.…”

“…Pánek et al. (, ,b) described “acristate mitochondria (hydrogenosomes)” in obligate heterolobosean anaerobes or microaerophils. For structures similar to hydrogenosomes in which putative cristae could be recognized only exceptionally they coined the term “mitochondrion‐related organelles (MROs)”.…”

“…), led Pánek et al. () to consider existence of a complex metabolism in some anaerobic heteroloboseans that they described as new species.…”

“…Moreover, surprising details of the ultrastructure of microaerophilic or anaerobic heteroloboseans (Pánek and Cepicka ; Pánek et al. ,b) advocate revision of heterolobosean characteristics.…”

“…) of immensely diverse protists (Pánek and Cepicka ; Pánek et al. , ). Of those, the most attention has been paid to vahlkampfiids (Vahlkampfiidae Jollos, ).…”