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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., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

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.

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.