Light microscopic observations, ultrastructure, and molecular phylogeny of Hicanonectes teleskopos n. g., n. sp., a deep-branching relative of diplomonads.
We describe Hicanonectes teleskopos n. g., n. sp., a heterotrophic flagellate isolated from low-oxygen marine sediment. Hicanonectes teleskopos has a ventral groove and two unequal flagella, and rapidly rotates during swimming. At the ultrastructural level H. teleskopos is a "typical excavate": it displays flagellar vanes, a split right microtubular root, "I,""B," and "C" fibres, a singlet microtubular root, and a possible composite fibre. Small subunit rRNA (SSU rRNA) gene phylogenies and an "arched" B fibre demonstrate that H. teleskopos belongs to Fornicata (i.e. diplomonads, retortamonads, and relatives). It forms a clade with the deep-branching fornicate Carpediemonas, with moderate-to-strong bootstrap support, although their SSU rRNA gene sequences are quite dissimilar. Hicanonectes differs from Carpediemonas in cell shape, swimming behaviour, number of basal bodies (i.e. 4 vs. 3), number of flagellar vanes (i.e. 2 vs. 3), anterior root organization, and by having a cytopharynx. Like Carpediemonas and Dysnectes, Hicanonectes has conspicuous mitochondrion-like organelles that lack cristae and superficially resemble the hydrogenosomes of parabasalids, rather than the mitosomes of their closer relatives the diplomonads (e.g. Giardia).
Park
Jong Soo
JS
Canadian Institute for Advanced Research, Program in Integrated Microbial Diversity, and Department of Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4J1 Canada.
Kolisko
Martin
M
Heiss
Aaron A
AA
Simpson
Alastair G B
AG
D000818:Animals; D016054:DNA, Protozoan / Q000032:analysis / Q000235:genetics; D016828:Diplomonadida / Q000145:classification / Q000235:genetics / Q000648:ultrastructure; D005407:Flagella / Q000648:ultrastructure; D020459:Genes, rRNA; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D016054:DNA, Protozoan