Platysulcus tardus (from Latin platy 'wide' and sulcus 'furrow') is an eukaryotic microorganism that was recently discovered to be the earliest diverging lineage of the Heterokont phylogenetic tree.[1][2] It is the only member of the family Platysulcidae, order Platysulcida and class Platysulcea.
| Platysulcus | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Stramenopiles |
| Class: | Platysulcea Cavalier-Smith, 2017 |
| Order: | Platysulcida Cavalier-Smith, 2017 |
| Family: | Platysulcidae Shiratori, Nkayama & Ishida, 2015 |
| Genus: | Platysulcus Shiratori, Nakayama & Ishida, 2015 |
| Species: | P. tardus
|
| Binomial name | |
| Platysulcus tardus Shiratori, Nkayama & Ishida, 2015
| |
Morphology
editPlatysulcus 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.[1]
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.[1]
Ecology
editPlatysulcus was isolated from sedimented detritus on seaweed collected near Ngeruktabel Island, Palau. It is a free-living phagotrophic protist, bacterivorous and marine.[1]
Phylogeny and taxonomy
editPhylogeny
editPhylogenetic analyses recover Platysulcea as the earliest diverging lineage of Stramenopiles, sister to a clade containing Bigyra and Gyrista.[3]
| Stramenopiles |
| ||||||
Taxonomy
editDespite the phylogenetic results, Platysulcea has been classified as part of the phylum Bigyra.[4]
- Class Platysulcea Cavalier-Smith, 2017
- Order Platysulcida Cavalier-Smith, 2017
- Family Platysulcidae Shiratori, Nkayama & Ishida, 2015
- Platysulcus Shiratori, Nkayama & Ishida, 2015
- P. tardus Shiratori, Nkayama & Ishida, 2015
- Platysulcus Shiratori, Nkayama & Ishida, 2015
- Family Platysulcidae Shiratori, Nkayama & Ishida, 2015
- Order Platysulcida Cavalier-Smith, 2017
References
edit- ^ a b c d Shiratori, Takashi; Nakayama, Takeshi; Ishida, Ken-ichiro (2015). "A New Deep-branching Stramenopile, Platysulcus tardus gen. nov., sp. nov". Protist. 166 (3): 337–348. doi:10.1016/j.protis.2015.05.001. hdl:2241/00148461. ISSN 1434-4610. PMID 26070192.
- ^ Shiratori, Takashi; Thakur, Rabindra; Ishida, Ken-ichiro (2017). "Pseudophyllomitus vesiculosus (Larsen and Patterson 1990) Lee, 2002, a Poorly Studied Phagotrophic Biflagellate is the First Characterized Member of Stramenopile Environmental Clade MAST-6". Protist. 168 (4): 439–451. doi:10.1016/j.protis.2017.06.004. ISSN 1434-4610. PMID 28822908.
- ^ Thakur R, Shiratori T, Ishida KI (November 2019). "Taxon-rich Multigene Phylogenetic Analyses Resolve the Phylogenetic Relationship Among Deep-branching Stramenopiles". Protist. 170 (5): 125682. doi:10.1016/j.protis.2019.125682. PMID 31568885.
- ^ Cavalier-Smith, Thomas (5 September 2017). "Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences". Protoplasma. 255 (1): 297–357. doi:10.1007/s00709-017-1147-3. PMC 5756292. PMID 28875267.
External links
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