| Tetradimorpha pterbica | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | incertae sedis |
| Genus: | Tetradimorpha |
| Species: | T. pterbica |
| Binomial name | |
| Tetradimorpha pterbica Mikrjukov and Patterson in Mikrjukov, 2000 | |
| Synonyms | |
| |
Tetradimorpha pterbica (from Latin tetra- 'four' and helio- 'sun') is a species of four-ciliated protists.
Description
Tetradimorpha pterbica are unicellular ciliates with four standard-length centrioles that are shorter than in Heliomorpha and other[1] Tetradimorpha, and axopodia generated by a globular centrosome with a distinct granular shell and a microfibrillar core. The centrioles are arranged in two pairs: each pair has two parallel centrioles, and the pairs are positioned at 30° of rotation between each other. They are linked at the base by an amorphous material that connects them to the centrosome. There are lateral dictyosomes on either side of the cell nucleus. The axopodia have several irregularly arranged microtubules and irregularly flattened extrusomes, instead of the kinetocysts seen in Heliomorpha and Tetradimorpha radiata. The cell size is larger than 60 μm, and the centrosome itself measures between 18 and 20 μm. There is a thick pseudopellicle layer beneath the cell membrane.[2]
The life cycle of Tetradimorpha pterbica contains a lazily swimming, purely flagellate stage with fully retracted axopodia.[2]
Classification
Cavalier-Smith proposed to assign this species to a new monotypic cryptist genus, Tetrahelia. He uses Endohelea in Cryptista for Microheliella and Tetrahelia, but this is incompatible with the current consensual classification, as Microheliella was described as a non-cryptist but Cavalier-Smith later assigned it to Cryptista, but this did not meet consensus, Pancryptista contains Cryptista and Microheliella.[2][3][4] The species is within Tetradimorpha[1] and the genus is incertae sedis within eukaryotes.[4]
References
- Mikrjukov, Kirill A. (2000). "Taxonomy and Phylogeny of Heliozoa. I. The Order Desmothoracida Hertwig et Lesser, 1874" (PDF). Digital Repository of Scientific Institutes. Retrieved 21 June 2026.
- Cavalier-Smith, Thomas (2022-05-01). "Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi". Protoplasma. 259 (3): 487–593. doi:10.1007/s00709-021-01665-7. ISSN 1615-6102. PMC 9010356. PMID 34940909.
- Yazaki, Euki; Yabuki, Akinori; Imaizumi, Ayaka; Kume, Keitaro; Hashimoto, Tetsuo; Inagaki, Yuji (2022-04-13). "The closest lineage of Archaeplastida is revealed by phylogenomics analyses that include Microheliella maris". Open Biology. 12 (4) 210376. doi:10.1098/rsob.210376. PMC 9006020. PMID 35414259.
- Adl, Sina M.; Bass, David; Lane, Christopher E.; Lukeš, Julius; Schoch, Conrad L.; Smirnov, Alexey; Agatha, Sabine; Berney, Cedric; Brown, Matthew W.; Burki, Fabien; Cárdenas, Paco; Čepička, Ivan; Chistyakova, Lyudmila; del Campo, Javier; Dunthorn, Micah (2019). "Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes". Journal of Eukaryotic Microbiology. 66 (1): 4–119. doi:10.1111/jeu.12691. ISSN 1550-7408. PMC 6492006. PMID 30257078.