Morphological Variability of Testate Amoebae (Rhizopoda: Testacealobosea: Testaceafilosea) in Natural Populations

Morphometric investigation of 24 species of testate amoebae (Centropyxis sylvatica (Deflandre) Thomas, Cyclopyxis eurystoma v. parvula Deflandre, C. puteus Thomas, Hyalosphenia papilio Leidy, H. elegans Leidy, Schoenbornia humicola (Schoenborn) Decloitre, Difflugia acuminata Ehrenberg, D. corona Wallich, D. gramen Penard, D. labiosa Wailes, D. lanceolata Penard, D. limnetica (Levander) Penard, D. lithophila Penard, D. lobostoma Leidy, D. oblonga Ehrenberg, D. parva Ogden, D. pyriformis Perty, D. urceolata Carter, Phryganella acropodia (Hertwig et Lesser) Hopkinson, Assulina muscorum Greef, Tracheleuglypha acolla Bonnet, Thomas, Trinema lineare Penard, Wailesella eboracensis (Wailes) Deflandre, Difflugiella oviformis f. fusca (Penard) Bonnet et Thomas) is conducted. Variability of natural populations of testate amoebae is expressed either in the changes of the shell size (correlated), or in the changes of the size of separate parameters (non correlated), resulting in a significant broadening of phenotypic spectrum in populations. The size of shell aperture demonstrates the greatest variability. The character of variability (its amplitude and correlativity) differs not only in different species, but also in different populations of the same species. Three main types of size variability in testate amoebae populations are established. There are monomorphic populations, polymorphic populations with correlated characters and populations with a high phenotypic plasticity, non-correlated characters and the elements of discreteness. A scheme of the close related species analysis is proposed.