Heliomonadida

The Heliomonadida (formerly Dimorphida) are a small group of heliozoan amoeboids that are unusual in possessing flagella throughout their life cycle.

Classification

Genetic studies place them among the Cercozoa, a group including various other flagellates that form filose pseudopodia. This order has been placed into the new class of naked cercozoans called Granofilosea. There are two genera in this order:

• Heliomorpha, a tiny organism found in freshwater
• the larger Tetradimorpha, which is distinguished by having four rather than two flagella.

Morphology

Bundles of microtubules, typically in square array, arise from a body near the flagellar bases and support the numerous axopods that project from the cell surface.

Heliomonads have a single nucleus, and mitochondria with tubular cristae.

References