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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. [ABSTRACT FROM AUTHOR]

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Abstract: Since its description 35 years ago from Quebec, Canada, the poorly known monospecific testate rhizopod genus Puytoracia (type species, Puytoracia bergeri) has been reported only from the Himalayan region of Nepal. This species was recently found at 13 locations in Ontario, Canada, and the range of form variation of the species from widely separated sites is described. At two of these sites, boreal forest bogs in north-western Ontario, a second, previously unidentified, Puytoracia species was also found and described (as Puytoracia bonneti n. sp.). Differences between the two species were clearly demonstrated statistically using morphometric variables. The large elliptical scales covering the test of P. bonneti (easily seen with relatively low-power microscopy) provide the most important criterion for separating this species from some Trinema species having superficially similar test morphology (e.g. Trinema penardi Thomas & Chardez, or Trinema galeata (Penard) Jung.). On the basis of test structure, it is suggested that P. bonneti occupies a taxonomic position relative to P. bergeri that is similar to that occupied by T. penardi relative to Trinema enchelys (Ehr.) Leidy. Results of this study further confirm the logical position of Puytoracia within the family Trinematidae, close to, but distinct from, the genera Corythion and Trinema. [Copyright &y& Elsevier]

Proposes the use of fuzzy cluster membership weights for ranking species important in a classification of the sampling unit, using crustacean-zooplankton data from Lake Simcoe in Ontario. Identification of elements of interannual and spatial variability in the crustacean zooplankton; Other aspects of crustacean zooplankton community structure.

Two new species of Pseudokephyrion are described from Little Aurora Lake, Ontario, Canada. The distribution of both P. taeniatum sp. nov. and P. auroreum sp. nov. is restricted for reasons which are not clear; neither species was found in samples from lakes adjacent to Little Aurora Lake. All lakes in the vicinity are very dilute, oligotrophic and acidic. [ABSTRACT FROM AUTHOR]

The testate amoebid genus Corythionella inhabits beach sands and includes three marine and two freshwater species of the "acolla-complex", all characterized by a poorly developed flared collar surrounding the pseudostomal aperture. Multivariate statistical methods (cluster analysis, principal coordinates analysis, non-metric multidimensional scaling ordination and discriminant analyses) were applied to morphologic characters of the test (shell) of the members of this complex in order to visualize and assess the degree of similarity among them. Graphical displays of the results of these analyses clearly revealed distinct separations between all pairs of species, including a sixth previously un-named taxon described here as a new species (Corythionella darwini n. sp.). Discriminant functions were developed to assist in identification of Corythionella with reduced oral collars. C. darwini was discovered in Pacific Ocean beach sand samples from western Canada and is characterized by a test with a median length, width, height and pseudostome width of 53, 20, 19 and 12microm, respectively. It presents the least variability in test morphology of all known species in the "acolla-complex" (coefficients of variation ranging between 3 and 5.6% for the four test variables) and is further distinguished from the other members of the complex by its distinctive near-cylindrical shape.