Light microscopic observations, ultrastructure, and molecular phylogeny of Hicanonectes teleskopos n. g., n. sp., a deep-branching relative of diplomonads

J Eukaryot Microbiol. 2009 Jul-Aug;56(4):373-84. doi: 10.1111/j.1550-7408.2009.00412.x.

Abstract

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).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA, Protozoan / analysis
  • DNA, Protozoan / genetics
  • Diplomonadida* / classification
  • Diplomonadida* / genetics
  • Diplomonadida* / ultrastructure
  • Flagella / ultrastructure
  • Genes, rRNA
  • Microscopy, Electron, Transmission
  • Mitochondria / ultrastructure
  • Molecular Sequence Data
  • Phylogeny*
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Species Specificity

Substances

  • DNA, Protozoan

Associated data

  • GENBANK/FJ628363