Cladtertia
Cladtertia | |
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Microscopic image of Cladtertia collaboinventa. Scale bar is 0.2 mm. | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Placozoa |
Class: | Uniplacotomia |
Order: | Hoilungea |
Family: | Cladtertiidae Tessler et al., 2022 |
Genus: | Cladtertia Tessler et al., 2022 |
Type species | |
Cladtertia collaboinventa Tessler et al., 2022
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Other haplotypes | |
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Cladtertia is a genus of placozoan discovered in 2022, whose only currently described species is Cladtertia collaboinventa. However, the genus is known to contain several other species, awaiting a formal description. Its closest described relative is Hoilungia hongkongensis, with whom it forms the order Hoilungea. After Trichoplax, Hoilungia and Polyplacotomia, it is the fourth extant placozoan genus to be described.[1]
Etymology
[edit]The genus name comes from Ancient Greek kládos (clade) and Latin tertius (the third), referring to its specimens previously being assigned to placozoan Clade III in literature.[2]
Biology
[edit]Cladtertia is morphologically indistinguishable under light microscopy from other placozoans in the class Uniplacotomia. All of them possess an amoeboid body with little branching, and have been described as "miniature pancakes".[3] However, Cladtertia is distinguished from its relatives at the genetic level.[4]
Uniquely among placozoans, sexual reproduction has been reported to occur in the placozoan clade identified with strain H8,[5][6] which was later found to belong to genus Cladtertia.[2] Intergenic recombination was inferred, with some individuals having identical genotypes on one locus but being highly dissimilar on other loci. This can not be achieved with asexual reproduction alone, which requires a complete linkage between regions of the genome.[7] The sharing of alleles between heterozygous and homozygous individuals was also observed, a phenomenon resulting from the combination of gametes during sexual reproduction.[8] A self-fertilization mating system was also excluded by the presence of both heterozygous and homozygous individuals.[6]
Taxonomy
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Placozoa_cladogram.jpg/220px-Placozoa_cladogram.jpg)
Placozoans were first divided in five clades in 2004 based on their 16S mitochondrial genome.[9][10] Clade III was later included in the genus Hoilungia.[11]
In 2022, as part of a wider formalization of placozoan taxonomy, Cladtertia was erected to encompass species previously placed in Clade III, with Cladtertia collaboinventa as its type species. It is the only genus in the family Cladtertiidae, which is sister to Hoilungidae in the order Hoilungea. Cladtertiidae is distinguished by 3 uniquely present and 8 uniquely missing genes.[2]
The exact number of species in placozoan genera is uncertain, as it is not known whether all haplotypes correspond to distinct species.[12] Only one species of Cladtertia, C. collaboinventa (formerly haplotype H23), has been formally described, in 2022. Haplotype H6 was confirmed as a distinct species, although it was left undescribed due to a lack of material from which to designate a type specimen.[4] Other haplotypes are known, such as Cladtertia H7, H8 and H16.[1] In a 2024 study, H6 was found to occupy a basal position in the genus compared to C. collaboinventa and H8, with the latter two sharing an inversion of the tRNA-Thr and tRNA-Lys region as a structural synapomorphy.[13]
Ecology and habitat
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Placozoan_range_map.png/220px-Placozoan_range_map.png)
Compared to other placozoan lineages, Cladtertia is only known from a restricted range of latitudes, from 26°N to 25°S, and has been sampled in the Pacific, Atlantic and Indian Oceans. A 2015 study found that Cladtertia's ecological niche differed from that of Clades I and V, and that surface temperature played a major role in predicted habitat suitability, with Cladtertia preferring warm tropical waters.[14] It is believed to prefer habitats with low seasonal changes, evidenced by a lack of observations in the Mediterranean Sea as of 2013.[15]
Cladtertia H6 was first discovered in Honolulu, Hawaii, where specimens were collected from water tables at the Kewalo Marine Laboratory.[16] The type specimen of C. collaboinventa was found in a sea water aquarium in Germany, and its actual geographical origin is unknown.[4]
Mitochondrial genomes of Cladtertia H6, alongside other placozoans, have been found in the rhodopid sea slug Helminthope sp. in marine sediment near Isla Iguana, Panama, providing evidence of predation by the latter on Cladtertia.[17]
References
[edit]- ^ a b Tessler et al. 2022a, p. 11.
- ^ a b c Tessler et al. 2022a, p. 14.
- ^ Tessler et al. 2022b, p. 5.
- ^ a b c Tessler et al. 2022a, p. 13.
- ^ Signorovitch, Dellaporta & Buss 2005, p. 15518–15519.
- ^ a b Charlesworth 2006, p. 341.
- ^ Signorovitch, Dellaporta & Buss 2005, p. 15520–15521.
- ^ Signorovitch, Dellaporta & Buss 2005, p. 15520.
- ^ Eitel et al. 2013, p. 4–5.
- ^ Voigt et al. 2004, p. 1.
- ^ Eitel et al. 2018, p. 11.
- ^ Tessler et al. 2022a, p. 10.
- ^ Eitel et al. 2024, p. 5.
- ^ Paknia & Schierwater 2015, p. 7–10.
- ^ Eitel et al. 2013, p. 10.
- ^ Laumer et al. 2018, p. 9.
- ^ Eitel et al. 2024, p. 3–4.
Works cited
[edit]- Charlesworth, D. (2006). "Population genetics: Using recombination to detect sexual reproduction: The contrasting cases of Placozoa and C. elegans". Heredity. 96 (5): 341–342. doi:10.1038/sj.hdy.6800809. PMID 16552431. S2CID 44333533.
- Eitel, Michael; Osigus, Hans-Jürgen; DeSalle, Rob; Schierwater, Bernd (2013-04-02). Browman, Howard (ed.). "Global Diversity of the Placozoa". PLOS ONE. 8 (4): e57131. Bibcode:2013PLoSO...857131E. doi:10.1371/journal.pone.0057131. ISSN 1932-6203. PMC 3614897. PMID 23565136.
- Eitel, Michael; Francis, Warren R.; Varoqueaux, Frédérique; Daraspe, Jean; Osigus, Hans-Jürgen; Krebs, Stefan; Vargas, Sergio; Blum, Helmut; Williams, Gray A.; Schierwater, Bernd; Wörheide, Gert (2018-07-31). Tyler-Smith, Chris (ed.). "Comparative genomics and the nature of placozoan species". PLOS Biology. 16 (7): e2005359. doi:10.1371/journal.pbio.2005359. ISSN 1545-7885. PMC 6067683. PMID 30063702.
- Eitel, Michael; Osigus, Hans-Jürgen; Brenzinger, Bastian; Wörheide, Gert (April 2024). "Beauty in the beast – Placozoan biodiversity explored through molluscan predator genomics". Ecology and Evolution. 14 (4): e11220. Bibcode:2024EcoEv..1411220E. doi:10.1002/ece3.11220. ISSN 2045-7758. PMC 11007570. PMID 38606341.
- Laumer, Christopher E.; Gruber-Vodicka, Harald; Hadfield, Michael G.; Pearse, Vicki B.; Riesgo, Ana; Marioni, John C.; Giribet, Gonzalo (2018-10-30). "Support for a clade of Placozoa and Cnidaria in genes with minimal compositional bias". eLife. 7. doi:10.7554/eLife.36278. ISSN 2050-084X. PMC 6277202. PMID 30373720.
- Paknia, Omid; Schierwater, Bernd (2015-11-18). Fontaneto, Diego (ed.). "Global Habitat Suitability and Ecological Niche Separation in the Phylum Placozoa". PLOS ONE. 10 (11): e0140162. Bibcode:2015PLoSO..1040162P. doi:10.1371/journal.pone.0140162. ISSN 1932-6203. PMC 4651326. PMID 26580806.
- Signorovitch, A.Y.; Dellaporta, S.L.; Buss, L.W. (2005). "Molecular signatures for sex in the Placozoa". Proceedings of the National Academy of Sciences of the United States of America. 102 (43): 15518–22. Bibcode:2005PNAS..10215518S. doi:10.1073/pnas.0504031102. PMC 1266089. PMID 16230622.
- Tessler, Michael; Neumann, Johannes S.; Kamm, Kai; Osigus, Hans-Jürgen; Eshel, Gil; Narechania, Apurva; Burns, John A.; DeSalle, Rob; Schierwater, Bernd (2022-12-08). "Phylogenomics and the first higher taxonomy of Placozoa, an ancient and enigmatic animal phylum". Frontiers in Ecology and Evolution. 10. doi:10.3389/fevo.2022.1016357.
- Tessler, Michael; Galen, Spencer C.; DeSalle, Rob; Schierwater, Bernd (2022-12-08). "Let's end taxonomic blank slates with molecular morphology". Frontiers in Ecology and Evolution. 10. doi:10.3389/fevo.2022.1016412. ISSN 2296-701X.
- Voigt, Oliver; Collins, Allen G.; Pearse, Vicki Buchsbaum; Pearse, John S.; Ender, Andrea; Hadrys, Heike; Schierwater, Bernd (November 2004). "Placozoa – no longer a phylum of one". Current Biology. 14 (22): R944–R945. Bibcode:2004CBio...14.R944V. doi:10.1016/j.cub.2004.10.036. PMID 15556848.
Further reading
[edit]- Najle, Sebastián R.; Grau-Bové, Xavier; Elek, Anamaria; Navarrete, Cristina; Cianferoni, Damiano; Chiva, Cristina; Cañas-Armenteros, Didac; Mallabiabarrena, Arrate; Kamm, Kai; Sabidó, Eduard; Gruber-Vodicka, Harald; Schierwater, Bernd; Serrano, Luis; Sebé-Pedrós, Arnau (October 2023). "Stepwise emergence of the neuronal gene expression program in early animal evolution". Cell. 186 (21): 4676–4693.e29. doi:10.1016/j.cell.2023.08.027. PMC 10580291. PMID 37729907.