Heliomonadida

The Heliomonadida^[1] (formerly Dimorphida^[2]) are a small group of heliozoan amoeboids that are unusual in possessing flagella throughout their life cycle.

Heliomonadida
Heliomorpha mutans (= Dimorpha mutans), fig. 9-11
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Phylum:	Cercozoa
Class:	Granofilosea
Order:	Heliomonadida Cavalier-Smith, 1993 emend. Cavalier-Smith, 2012
Family:	Heliomorphidae Cavalier-Smith & Bass 2009
Genera
Heliomorpha Cavalier-Smith & Bass 2009 Tetradimorpha Hsiung 1927

Classification

Genetic studies place them among the Cercozoa, a group including various other flagellates that form filose pseudopodia. This order has recently been placed into the new class of naked filose cercozoans called Granofilosea.^[1] 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.

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

References

1. Bass D, Chao EE, Nikolaev S, et al. (February 2009). "Phylogeny of novel naked Filose and Reticulose Cercozoa: Granofilosea cl. n. and Proteomyxidea revised". Protist. 160 (1): 75–109. doi:10.1016/j.protis.2008.07.002. PMID 18952499.
2. Nikolaev SI, Berney C, Fahrni JF, et al. (May 2004). "The twilight of Heliozoa and rise of Rhizaria, an emerging supergroup of amoeboid eukaryotes". Proc. Natl. Acad. Sci. U.S.A. 101 (21): 8066–71. doi:10.1073/pnas.0308602101. PMC 419558. PMID 15148395.