Foraminiferan protists build elaborate shells (called tests) using specialized pseudopods called reticulopodia. The cytoskeletal architecture of the reticulopod consists of bundles of microtubules with unusual assembly properties. These properties may be conferred by the highly divergent foraminiferal β-tubulin.

Top: an individual of the foraminiferal genus Homotrema. Bottom: a scanning electron micrograph of the test. Note the complex morphology of the test surface.