Gymnosphaerid

Gymnosphaerids
Scientific classification
Domain: Eukaryota
(unranked): SAR
(unranked): Rhizaria
Phylum: Cercozoa
Class: Granofilosea
Order: Gymnosphaerida
Poche, 1913
Species

Gymnosphaera elbida
Hedraiophrys hovassei
Actinocoryne contractilis

The gymnosphaerids (or Gymnosphaerida)[1] are a small group of heliozoan protists found in marine environments. They tend to be roughly spherical with radially directed axopods, supported by microtubules in a triangular-hexagonal array arising from an amorphous central granule.

Genera

There are only three genera, each with a single species: Gymnosphaera albida, Hedraiophrys hovassei, and Actinocoryne contractilis.

Classification

Gymnosphaerids were originally considered centrohelids, which also have microtubules in a triangular-hexagonal array, but are set apart from the others by the structure of the central granule and the mitochondria, which have tubular cristae. The two groups have been treated as separate orders (Axoplasthelida and Centroplasthelida) in a common class, but this has lost support. Instead the gymnosphaerids may be allied with the desmothoracids, and on account of this have been placed in the Cercozoa, but this is somewhat tentative.

References

  1. 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.
  2. Febvre-Chevalier C (1981). "Preliminary study of the motility processes in the stalked heliozoan Actinocoryne contractilis". Biosystems 14 (3-4): 337–343. doi:10.1016/0303-2647(81)90040-X. PMID 7337812.
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