Platysulcus
{{Short description|Genus of single-celled organisms}}
{{Speciesbox
| taxon = Platysulcus tardus
| authority = Shiratori, Nkayama & Ishida, 2015
| parent_authority = Shiratori, Nakayama & Ishida, 2015
| grandparent_authority = Shiratori, Nkayama & Ishida, 2015
| greatgrandparent_authority = Cavalier-Smith, 2017
| greatgreatgrandparent_authority = Cavalier-Smith, 2017
}}
Platysulcus tardus ({{etymology|lat|platy|wide||sulcus|furrow}}) is a eukaryotic microorganism that was recently discovered to be the earliest diverging lineage of the Heterokont phylogenetic tree.{{Cite journal| last= Shiratori| first= Takashi | last2= Nakayama | first2= Takeshi | last3= Ishida | first3= Ken-ichiro | title= A New Deep-branching Stramenopile, Platysulcus tardus gen. nov., sp. nov. | journal= Protist| date= 2015| volume= 166| issue= 3| pages= 337–348| issn= 1434-4610| doi= 10.1016/j.protis.2015.05.001| pmid=26070192| hdl= 2241/00148461 | url= https://tsukuba.repo.nii.ac.jp/?action=repository_uri&item_id=43574 | hdl-access= free}}{{cite journal|first1=Takashi|last1=Shiratori|first2=Rabindra|last2=Thakur|first3=Ken-ichiro|last3=Ishida|title=Pseudophyllomitus vesiculosus (Larsen and Patterson 1990) Lee, 2002, a Poorly Studied Phagotrophic Biflagellate is the First Characterized Member of Stramenopile Environmental Clade MAST-6|journal=Protist|volume=168|issue=4|date=2017|pages=439–451|issn=1434-4610|doi=10.1016/j.protis.2017.06.004|pmid=28822908 |url=https://www.sciencedirect.com/science/article/pii/S1434461017300561}} It is the only member of the family Platysulcidae, order Platysulcida and class Platysulcea.
Morphology
Platysulcus is a gliding biflagellate, with a short anterior flagellum, a long posterior flagellum, and a flagellar apparatus typical of stramenopiles. It has tubular mastigonemes on the anterior flagellum. It contains mitochondria with tubular cristae. The basal body and the transitional region of the flagella lack ring-shaped or helical structures. The two flagellar roots consist of 11 microtubules forming an “L”-shape.
Its cells are oval or ovoid in shape, around 5.62 μm in length and 3.76 μm in width. The anterior flagellum is around 9 μm in length, and the posterior measures around 17 μm. They contain extrusomes and a large, flat vesicle surrounding the cytoplasm where the nucleus, mitochondria, and microbodies are found.
Ecology
Platysulcus was isolated from sedimented detritus on seaweed collected near Ngeruktabel Island, Palau. It is a free-living phagotrophic protist, bacterivorous and marine.
Phylogeny and taxonomy
=Phylogeny=
Phylogenetic analyses recover Platysulcea as the earliest diverging lineage of Stramenopiles, sister to a clade containing Bigyra and Gyrista.{{cite journal|vauthors=Thakur R, Shiratori T, Ishida KI|title=Taxon-rich Multigene Phylogenetic Analyses Resolve the Phylogenetic Relationship Among Deep-branching Stramenopiles|journal=Protist|date=November 2019|volume=170|issue=5|pages=125682|doi=10.1016/j.protis.2019.125682|pmid=31568885}}
{{clade|style=font-size:90%;|label1=Stramenopiles|1={{clade|2=Platysulcus tardus|1={{clade|label2=Bigyra|2={{clade|1=Sagenista|2=Opalozoa}}|label1=Gyrista|1={{clade|1=Ochrophyta|2={{clade|1=Pseudofungi|2=Bigyromonadea}}}}}}}}}}
=Taxonomy=
Despite the phylogenetic results, Platysulcea has been classified as part of the phylum Bigyra.{{Cite journal |last=Cavalier-Smith |first=Thomas|date=5 September 2017 |title=Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences |journal=Protoplasma |volume=255|issue=1|pages=297–357 |doi=10.1007/s00709-017-1147-3|pmid=28875267|pmc=5756292}}
- Class Platysulcea {{au|Cavalier-Smith, 2017}}
- Order Platysulcida {{au|Cavalier-Smith, 2017}}
- Family Platysulcidae {{au|Shiratori, Nkayama & Ishida, 2015}}
- Platysulcus {{au|Shiratori, Nkayama & Ishida, 2015}}
- P. tardus {{au|Shiratori, Nkayama & Ishida, 2015}}
References
{{Reflist}}
External links
{{wikispecies}}
{{Eukaryota|D.}}
{{Heterokont}}
{{Taxonbar|from=Q26816869}}