Heliorapha
Heliorapha is a genus of heliozoan protists, amoeboid eukaryotes with stiff axopodia radiating from their cells. It contains one species, Heliorapha azurina (previously Ciliophrys azurina). It is classified within a monotypic family Helioraphidae inside the actinophryids, a group of heliozoa that belong to the Ochrophyta along with other protists such as diatoms and brown algae. Morphology Heliorapha azurina is a heliozoan, a unicellular protist with tapering arms called axopodia sustained by axonemes. Cells of H. azurina have a large, prominent cell nucleus containing a central nucleolus surrounded by peripheral clumps of heterochromatin. The cell body measures 15 µm in diameter, with radiating arms that contain extrusomes. Each cell has a single flagellum that appears at the front of swimming cells or, in non-swimming cells (i.e. during feeding), appears tightly curled, typically in a double "8" shape. Both its large size and the length and shape of its flagellum make it similar to Actinophrys, specifically A. pontica. Ecology Heliorapha azurina is a heterotrophic flagellate exclusively found in tropical climates, in both marine and terrestrial habitats. It was isolated from Darwin, Northern Territory, Australia, where it was observed consuming diatoms. It is present in intertidal sediments and surface waters of Darwin. It