Pedinellales

Pedinellids have been known since the 19th century, but were classified as either algae or heliozoan protozoa due to the absence of chloroplasts in some species.{{cite Q|Q125959734}} Before the taxonomic revisions that took place in the late 20th century, pedinellids were treated as a single family Pedinellaceae, described in 1910 by Pascher. Some authors classified pedinellids within the order Ochromonadales, together with a variety of unrelated heterokonts such as Synuraceae and Bicosoecaceae, as part of the class Chrysophyceae or golden algae.{{cite book|page=116|first1=Tyge|last1=Christensen|date=1980|publisher=AiO Tryk as|publication-place=Odense|url=https://archive.org/details/algaetaxonomicsu0000chri/page/116|url-access=registration|title=Algae: a taxonomic survey|volume=1}} In 1985, phycologists Birthe Zimmermann, Øjvind Moestrup and Guy Hällfors classified them as an independent order, Pedinellales.{{cite journal|last1=Zimmermann|first1=B.|last2=Moestrup|first2=Ø.|last3=Hällfors|first3=G.|date=1985|title=Chrysophyte or heliozoon: ultrastructural studies on a cultured species of Pseudopedinella (Pedinellales ord. nov.), with comments on species taxonomy|journal=Protistologica|volume=20|pages=591–612}} The same year, John J. Lee and coauthors segregated the phagotrophic (i.e. without chloroplasts) pedinellids as a different order Ciliophryida under the polyphyletic class Heliozoea. Other authors, such as Thomas Cavalier-Smith, went a step further and proposed treating pedinellids as a separate class, under the name of Pedinellea (spelt Pedinellophyceae under botanical nomenclature).{{cite book|title=Chrysophyte algae: ecology, phylogeny, and development|pages=75–92|url=https://archive.org/details/chrysophytealgae0000unse/page/78|url-access=registration|date=1995|first1=Øjvind|last1=Moestrup|author1-link=Øjvind Moestrup|chapter=Current status of chrysophyte ‘splinter groups’: synurophytes, pedinellids, silicoflagellates|editor-first1=Craig D.|editor-last1=Sandgren|editor-first2=John P.|editor-last2=Smol|editor-first3=Jørgen|editor-last3=Kristiansen|publisher=Cambridge University Press|isbn=0521462606}}

In 1995, Charles J. O'Kelly and Daniel E. Wujek classified the Dictyochophyceae in three orders: Rhizochromulinales (containing the sole genus Rhizochromulina), Pedinellales (containing all pedinellids) and Dictyochales (silicoflagellates), separating them from golden algae.{{cite book|title=Chrysophyte algae: ecology, phylogeny, and development|pages=361–372|url=https://archive.org/details/chrysophytealgae0000unse/page/361|url-access=registration|date=1995|first1=Charles J.|last1=O'Kelly|first2=Daniel E.|last2=Wujek|chapter=Staus of the Chrysamoebales (Chrysophyceae): observations on Chrysamoeba pyrenoidifera, Rhizochromulina marina and Lagynion delicatum|editor-first1=Craig D.|editor-last1=Sandgren|editor-first2=John P.|editor-last2=Smol|editor-first3=Jørgen|editor-last3=Kristiansen|publisher=Cambridge University Press|isbn=0521462606}} Simultaneously, Cavalier-Smith proposed a slightly different classification where he created a new class Actinochrysea to embrace these three groups, avoiding the usage of Dictyochophyceae as a name. He considered pedinellids as subclass Pedinellidae, with two orders: Pedinellales (with chloroplasts), containing the families Pedinellaceae and Apedinellaceae; and Ciliophryales (without chloroplasts), containing Actinomonadaceae and Ciliophryaceae. The remaining two groups, Rhizochromulinales and Dictyochales, were transferred to a separate subclass Dictyochidae. The next year, Cavalier-Smith and Ema E. Chao recognized that the chloroplast losses were polyphyletic, and the family Actinomonadaceae was transferred to Pedinellales on the basis of a molecular phylogenetic analysis.{{cite journal|title=18S rRNA sequence of Heterosigma carterae (Raphidophyceae), and the phylogeny of heterokont algae (Ochrophyta)|journal=Phycologia|first1=T.|last1=Cavalier-Smith|first2=E.E.|last2=Chao|volume=35|issue=6|pages=500–510|doi=10.2216/i0031-8884-35-6-500.1|date=1996}}

In 2006, Cavalier-Smith once again rearranged the classification. He lowered Actinochrysea to a subclass Actinochrysia within a new class Hypogyristea, which also included pelagophytes as subclass Pelagophycia. He lumped together all pedinellid genera in the family Actinomonadaceae and new suborder Actinomonadineae, with the exception of Ciliophrys, which he included with the non-pedinellid Rhizochromulina in two families of a new suborder Ciliophryineae. He maintained this classification in later years. In 2018, he finally recognized class Dictyochophyceae, and created the subclass Pedinellia or Pedinellophycidae (equivalent to his earlier Actinochrysea/Actinochrysia) to lump together pedinellids and silicoflagellates. Pelagophytes remained under the subclass Pelagophycidae, and two genera of more uncertain placement under a third subclass Sulcophycidae: Olisthodiscus and Sulcochrysis.{{cite Q|Q47194626}}

Cavalier-Smith's taxonomic scheme is not accepted by the scientific community. Instead, Moestrup's 1995 classification is more commonly supported, where pedinellids are all contained in the order Pedinellales, rendering Ciliophryales a junior synonym. They are considered part of Dictyochophyceae, along with orders Dictyochales (silicoflagellates), Rhizochromulinales (Rhizochromulina),{{cite book|last1=Preisig|first1=Hans R.|date=1999|chapter=Systematics and Evolution of the Algae: Phylogenetic Relationships of Taxa Within the Different Groups of Algae|editor-first1=K.|editor-last1=Esser|editor-first2=J.W.|editor-last2=Kadereit|editor-first3=U.|editor-last3=Lüttge|editor-first4=M.|editor-last4=Runge|title=Progress in Botany|volume=60|publisher=Springer|publication-place=Berlin|doi=10.1007/978-3-642-59940-8_14|pages=369–412}} and a more recent fourth order Florenciellales.{{cite journal|title=Verrucophora farcimen gen. et sp. nov. (Dictyochophyceae, Heterokonta)—a bloom-forming ichthyotoxic flagellate form the Skagerrak, Norway|first1=Bente|last1=Edvardsen|first2=Wenche|last2=Eikrem|journal=Journal of Phycology|volume=43|pages=1054–1070|date=2007|doi=10.1111/j.1529-8817.2007.00390.x|hdl=10852/11590|hdl-access=free}} In addition, pelagophytes are rejected as members of Dictyochophyceae, and instead form an independent class Pelagophyceae.{{cite Q|Q57086550}} Within pedinellids, there have been several attempts to establish different families according to morphological data such as the presence or absence of stalks and chloroplasts. However, molecular analyses do not support these internal divisions. Consequently, all pedinellids have been grouped into a single family, Actinomonadaceae, which has taxonomic preference due to being the earliest described, and all other proposed families (Pedinellaceae, Apedinellaceae, etc.) have become junior synonyms.{{cite book | chapter = Class Silicoflagellata Lemmermann, 1901 | first1 = Øjvind | last1 = Moestrup | first2 = Charles J. | last2 = O'Kelly | title = An Illustrated Guide to the Protozoa | edition = 2nd | editor-first1 = John J. | editor-last1 = Lee | editor-first2 = Gordon F. | editor-last2 = Leedale | editor-first3 = Phyllis | editor-last3 = Bradbury | publisher = Society of Protozoologists | publication-place = Lawrence, Kansas | date = 2000 | url = https://protistologists.org/publications/illustrated-guide-to-the-protozoa/ | volume = II | pages = 775–782 | chapter-url = https://protistologists.org/wp-content/uploads/2023/07/17SILICOFLAGELLATA.pdf}}

Pedinellids currently sum the following genera:{{cite journal |author1=Guiry, M.D. |author2=Guiry, G.M.|name-list-style=amp |year=2016 |title=Dictyochophyceae | website=AlgaeBase |publisher=National University of Ireland, Galway | url=http://www.algaebase.org/browse/taxonomy/?id=4330}}{{Cite journal| last1=Cavalier-Smith | first1=Thomas | last2=Scoble | first2=Josephine Margaret |title=Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes | journal=European Journal of Protistology | date=2013 | volume=49 | issue= 3| pages=328–353 | doi= 10.1016/j.ejop.2012.09.002| pmid= 23219323}}

• Cyrtophora Strand 1929
• Palatinella Lauterborn 1906
• Actinomonas Kent 1880
• Apedinella Throndsen 1971
• Ciliophrys Cienkowski 1876
• Helicopedinella Sekiguchi et al. 2003
• Mesopedinella Daugbjerg 1996
• Parapedinella Pedersen, Beech & Thomsen 1986
• Pedinella Wyssotzki 1887 non Dahl 1909
• Pseudopedinella Carter 1937
• Pteridomonas Penard 1889

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{{cite journal|journal = Archiv für Protistenkunde | vauthors = Cavalier-Smith T, Chao EE, ((Allsopp MTEP))|title=Ribosomal RNA Evidence for Chloroplast Loss within Heterokonta: Pedinellid Relationships and a Revised Classification of Ochristan Algae|volume=145|pages=209–220|issue=3–4|date=1995|doi=10.1016/S0003-9365(11)80316-7}}

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Category:Ochrophyte orders

Category:Dictyochophyceae

Category:Taxa described in 1880