Pedinellales

Pedinellales is a group of single-celled algae found in both marine environments and freshwater.[1]

Pedinellales
Pteridomonas pulex, fig. 6-7; Actinomonas mirabilis, fig. 8
Scientific classification
Clade:	SAR
Phylum:	Ochrophyta
Class:	Dictyochophyceae
Order:	Pedinellales Zimmermann, Moestrup & Hallfors 1984
Families
Cyrtophoraceae Pedinellaceae
Synonyms
Pedinellida Zimmermann, Moestrup & Hallfors 1984 Actinomonadineae Cavalier-Smith 2006 Ciliophryineae Febvre-Chevalier ex Cavalier-Smith 2006 Ciliophryida Febvre-Chevalier 1985

These are found in both freshwater and marine environments, and most genera are sessile, attached by posterior stalks. The flagellum is at the anterior of the cell, and the tentacles surround it, often capturing small prey drawn in by its current. The colored genera are Pedinella, Apedinella, Pseudopedinella, and Mesopedinella. Several more genera have lost their chloroplasts and feed entirely by phagocytosis. These are Parapedinella, Actinomonas, and Pteridomonas.

It also appears that certain heliozoa are actually derived pedinellids. Ciliophrys alternates between a mobile flagellate stage and a heliozoan feeding stage, where the body is contracted with extended axopods all over its surface, and the flagellum is curled up into a tight figure eight. The actinophryids, Actinophrys and Actinosphaerium, exist only in a heliozoan form with no flagellum and with more elaborate bundles of microtubules supporting their axopods. Their inclusion was argued by Mikrjukov and Patterson, who coined the term actinodine to refer specifically to this extended group.

Pedinellids were classified as heliozoans by some authors. The colored pedinellids were originally treated as a family of golden algae in the order Ochromonadales, promoted to an order Pedinellales by Zimmerman in 1984. Their relationship to the silicoflagellates became apparent some time later, and Patterson defined this rankless group for the two in 1994. Moestrup treated it as the class Dictyochophyceae, previously restricted to the silicoflagellates, while Cavalier-Smith defined a new class Actinochrysophyceae for them.

Taxonomy

Taxonomy provided by AlgaeBase.[2][3]

• Family Cyrtophoraceae Pascher 1911
  • Genus Cyrtophorana Strand 1929
  • Genus Palatinella Lauterborn 1906
• Family Pedinellaceae Pascher 1910 [Actinomonadaceae Kent 1880; Ciliophryidae Poche 1913; Pedinellidae Cavalier-Smith 1986 stat. nov. 1995; Pseudopedinellaceae]
  • Genus Actinomonas Kent 1880
  • Genus Apedinella Throndsen 1971
  • Genus Ciliophrys Cienkowski 1876
  • Genus Helicopedinella Sekiguchi et al. 2003
  • Genus Mesopedinella Daugbjerg 1996
  • Genus Parapedinella Pedersen, Beech & Thomsen 1986
  • Genus Pedinella Wyssotzki 1887 non Dahl 1909
  • Genus Pseudopedinella Carter 1937
  • Genus Pteridomonas Penard 1889

References

1. Lee RE (March 2018). "Heterokontophyta - Dictyochochyceae". Phycology (5 ed.). Cambridge University Press. p. 345. ISBN 9781107555655. Retrieved 28 August 2018.
2. Guiry, M.D. & Guiry, G.M. (2016). "Dictyochophyceae". AlgaeBase. National University of Ireland, Galway.
3. Cavalier-Smith, Thomas; Scoble, Josephine Margaret (2013). "Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes". European Journal of Protistology. 49 (3): 328–353. doi:10.1016/j.ejop.2012.09.002. PMID 23219323.