Stephanopogon

Stephanopogon
Stephanopogon sp.
Scientific classification
Domain: Eukaryota
Phylum: Percolozoa
Class: Percolatea
Order: Pseudociliatida
Corliss & Lipscomb 1982
Genus: Stephanopogon
Entz 1884

Stephanopogon is a peculiar marine protozoan.

Characteristics

It closely resembles certain ciliates and was originally classified with them, but is now considered a flagellate. The cell is somewhat flattened, with multiple smooth flagella arranged in rows running from the front to the back, and has an anterior mouth supported by rods. They feed on bacteria, diatoms, and other smaller organisms. There are 2-16 nuclei, but they are not differentiated into macronuclei and micronuclei as occurs in ciliates.

Classification

Because the nuclei are homogeneous, Stephanopogon has previously been regarded as an evolutionary intermediate between the ciliates and other protozoa, and possibly an ancestor of the animals as well. However, Corliss and Lipscomb showed that it is not related to ciliates, and lacks their complex pellicle and infraciliature.[1] Stephanopogon has mitochondria with discoid cristae and lacks dictyosomes, like the Percolozoa. These morphological comparisons are consistent with the molecular phylogenetic analyses by Yubuki and Leander,[2] which demonstrated that Stephanopogon is closely related to Percolomonas within the Heterolobosea.

It has recently been placed in the class Percolatea, along with Percolomonas.[3]

References

  1. ↑ Corliss, J.O. and Lipscomb, D.L. (1982). "Establishment of new order in kingdom Protista for Stephanopogon, long-known "ciliate" revealed now as a flagellate". Journal of Protozoology 92: 294.
  2. ↑ Yubuki N, Leander BS (November 2008). "Ultrastructure and molecular phylogeny of Stephanopogon minuta: an enigmatic microeukaryote from marine interstitial environments". Eur. J. Protistol. 44 (4): 241–53. doi:10.1016/j.ejop.2007.12.001. PMID 18403188.
  3. ↑ Cavalier-Smith T, Nikolaev S (2008). "The zooflagellates Stephanopogon and Percolomonas are a clade (class Percolatea: Phylum Percolozoa)". J. Eukaryot. Microbiol. 55 (6): 501–9. doi:10.1111/j.1550-7408.2008.00356.x. PMID 19120795.

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