| Tunicaraptor | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Clade: | Amorphea |
| Clade: | Obazoa |
| Clade: | Opisthokonta |
| Clade: | Holozoa |
| Genus: | Tunicaraptor Tikhonenkov et al. 2020 |
| Species: | T. unikontum |
| Binomial name | |
| Tunicaraptor unikontum Tikhonenkov et al. 2020[1] | |
Tunicaraptor is a genus ofmarinemicrobialprotists containing the single speciesTunicaraptor unikontum, discovered in 2020 frommarine waters ofChile. It is a lineage ofpredatorialflagellates closely related to animals. It has a rare feeding structure not seen in other opisthokonts.[1]
Tunicaraptor unikontum is a smallunicellular flagellate composed of ovalcells similar to somefungalzoospores, with a length of 3–5μm. It has oneflagellum with a flagellar pocket, and an external envelope or 'theca' with long hairs of around 110nm. Unlike other unicellularopisthokonts,Tunicaraptor cells possess a 'mouth', a specialized feeding structure in theanterior part of thecell. There are twocentrioles: one develops a flagellum and the other rotates to thekinetosome. Themitochondrialcristae are flat and associated withlipid globules.[1]
Tunicaraptor unikontum was isolated from marine waters of the coast ofChile. Its morphology and phylogenetic relationships were analyzed and published in 2020 in thejournalCurrent Biology. The nameTunicaraptor means 'predator covered with tunica', whileunikontum (from Latin unus 'one' and Ancient Greek κοντός 'pole') means 'singleflagellum'.[1]
Tunicaraptor unikontum is found in marine environments. It is a eukaryovorous predator, meaning it can only feed on othereukaryotes, and it is not capable of consumingbacteria. During feeding, many different cells can aggregate and feed jointly on the same eukaryotic prey.[1]
Tunicaraptor is an independent lineage ofHolozoan protists, but its placement is not resolved. Three different phylogenetic positions ofTunicaraptor have been obtained from analyses: as sister toFilasterea, as sister toFilozoa or as the sister group to all Holozoa.[1][2] The characteristics of theRel homology region of thefilastereanTxikispora philomaios was highly similar toTunicaraptor unikontum, suggesting aphylogenetic relationship between the two species.[3]
In search for thegenes responsible foranimalmulticellularity across the eukaryote evolution, a precursor for aneuropeptide gene,nesfatin-1, has also been found inTunicaraptor unikontum. These discoveries suggest that neuropeptide signaling in animals has a deep evolutionary ancestry in their unicellular relatives.[4]
