A multivariate statistical evaluation of the “acolla-complex” of Corythionella species, including a description of C. darwini n. sp. (Rhizopoda: Filosea or Rhizaria: Cercozoa)

Marine and freshwater centrohelid heliozoans (Haptista: Centroplasthelida) in Canada, including taxonomic revisions and descriptions of 22 new species and subspecies

Canadian coastal waters of the Pacific Ocean and the Atlantic Ocean as well as inland freshwater habitats in Ontario were sampled for centrohelid heliozoans (free-living heterotrophic single-celled organisms) over a period of nearly five decades. More than 60 species and subspecies were revealed, including 1 Triangulopteris, 1 Raphidocystis, 2 Pseudoraphidocystis, 3 Raineriophrys, 4 Pseudoraphidiophrys, 12 Choanocystis, 15 Pterocystis, and 25 Acanthocystis taxa. Of these, 22 were officially named and described as new to science based primarily on the morphology of the siliceous scales that cover the cell. New species were compared with images and/or descriptions of close “relatives” to validate their new species assignments. New data on five species of Acanthocystis and one species of Choanocystis required revisions of their descriptive taxonomy that in some cases resulted in the splitting off of separate species or subspecies. Very little can be concluded about global distribution of centrohelid heliozoans, owing to the paucity of records. For many of the taxa reported here, previous records consist of just one or two findings from other parts of the world. One example is Choanocystis antarctica Tikhonenkov and Mylnikov, 2011 that was previously known only from Antarctic seawater, but is reported here from an Ontario softwater lake.

Local and intercontinental comparisons of test morphology in the little-known testate amoeba Cyphoderia laevis Penard

The morphology of tests ("shells") representing populations of the small testate amoeba Cyphoderia laevisPenard, 1902 (Cercozoa, Euglyphida) from Canada and Hungary was quantified. Despite often considerable variation the cross-sectional shape of tests, multivariate statistical analysis confirmed the general uniformity of test morphology within populations and between populations at both local (regional, inter- and intra-watershed) scales and over inter-continental scales (Canada and Hungary). Corrections are suggested to recently published misidentifications of C. laevis as Corythionella georgiana Nicholls. The differences between these two taxa are subtle, but significant, and are emphasized here to help preclude similar errors in the future. Schaudinnula nanaBadewitz, 2003 is shown to be a superfluous synonym for Cyphoderia laevis. Cyphoderia truncataSchulze, 1875 has some similarities to C. laevis, but its status remains unresolved. Some preliminary reservations are expressed about the classification of Cyphoderia laevis within the genus Cyphoderia owing mainly to its Corythionella-like scale structure and other characteristics of its test that appear to be outside the "usual" range found in other Cyphoderia species.

Applications of next-generation sequencing to unravelling the evolutionary history of algae

First-generation Sanger DNA sequencing revolutionized science over the past three decades and the current next-generation sequencing (NGS) technology has opened the doors to the next phase in the sequencing revolution. Using NGS, scientists are able to sequence entire genomes and to generate extensive transcriptome data from diverse photosynthetic eukaryotes in a timely and cost-effective manner. Genome data in particular shed light on the complicated evolutionary history of algae that form the basis of the food chain in many environments. In the Eukaryotic Tree of Life, the fact that photosynthetic lineages are positioned in four supergroups has important evolutionary consequences. We now know that the story of eukaryotic photosynthesis unfolds with a primary endosymbiosis between an ancestral heterotrophic protist and a captured cyanobacterium that gave rise to the glaucophytes, red algae and Viridiplantae (green algae and land plants). These primary plastids were then transferred to other eukaryotic groups through secondary endosymbiosis. A red alga was captured by the ancestor(s) of the stramenopiles, alveolates (dinoflagellates, apicomplexa, chromeridae), cryptophytes and haptophytes, whereas green algae were captured independently by the common ancestors of the euglenophytes and chlorarachniophytes. A separate case of primary endosymbiosis is found in the filose amoeba Paulinella chromatophora, which has at least nine heterotrophic sister species. Paulinella genome data provide detailed insights into the early stages of plastid establishment. Therefore, genome data produced by NGS have provided many novel insights into the taxonomy, phylogeny and evolutionary history of photosynthetic eukaryotes.