A new centrohelid heliozoan, Pterocystis polycristalepis sp. nov., and taxonomic and phylogenetic concerns within Pterista (Haptista: Centroplasthelida).

A new species of centrohelid heliozoans, Pterocystis polycristalepis sp. nov. (Pterocystidae), was examined using light and electron microscopy.

Unexpected ubiquity of heart-shaped scale morphotype in Centroplasthelida (Haptista): Ancestral trait or multiple acquisitions?

Centrohelids (Haptista: Centroplasthelida) are axopodial protists with a remarkable diversity of external siliceous scale morphologies. It is believed that the last common ancestor of centrohelids had a double layer of siliceous scales composed of plate scales closer to a cell surface and spine scales radiating outwards. The characteristic morphotype of spine scales with a heart-shaped base was once believed to be a unique feature of the genus Choanocystis, as it was defined by Siemensma and Roijackers (1988).

Microbial predators form a new supergroup of eukaryotes.

Molecular phylogenetics of microbial eukaryotes has reshaped the tree of life by establishing broad taxonomic divisions, termed supergroups, that supersede the traditional kingdoms of animals, fungi and plants, and encompass a much greater breadth of eukaryotic diversity. The vast majority of newly discovered species fall into a small number of known supergroups. Recently, however, a handful of species with no clear relationship to other supergroups have been described, raising questions about the nature and degree of undiscovered diversity, and exposing the limitations of strictly molecular-based exploration.

Centrohelid heliozoans of Ukraine with a description of a new genus and species (Haptista: Centroplasthelida).

New data on the species diversity and morphology of centrohelid heliozoans in freshwater, marine, and soil habitats of Ukraine were obtained. Cell coverings (scales and spicules) were observed using scanning and transmission electron microscopy. Eighteen species from seven genera of centrohelids and unidentifiable Heterophrys-like organisms were revealed.

Morphology and spicules elemental composition of Marophrys nikolaevi spec. nov. (Haptista: Centroplasthelida).

Marophrys is a genus of spicules-bearing centrohelids belonging to Heterophrys-like organisms (HLO's). Here Marophrys nikolaevi spec. nov.

On the origin of TSAR: morphology, diversity and phylogeny of Telonemia.

Telonemia is a poorly known major phylum of flagellated eukaryotes with a unique combination of morphological traits. Phylogenomics recently revealed the phylogenetic position of telonemids as sister to SAR, one of the largest groups of eukaryotes, comprising Stramenopiles, Alveolata and Rhizaria. Due to this key evolutionary position, investigations of telonemids are of critical importance for elucidating the origin and diversification of an astounding diversity of eukaryotic forms and life strategies.