Volvulina
| Volvulina | |
|---|---|
| |
| Volvulina steinii | |
Scientific classification 
| |
| Clade: | Viridiplantae |
| Division: | Chlorophyta |
| Class: | Chlorophyceae |
| Order: | Chlamydomonadales |
| Family: | Volvocaceae |
| Genus: | Volvulina Playfair |
| Type species | |
| Volvulina steinii Playfair[1]
| |
| Species[1] | |
Volvulina is a genus of colonial green algae in the family Volvocaceae.[2] It is cosmopolitan, but rare.[1]
Description
[edit]Volvulina is a multicellular organism. The colony, termed a coenobium, is broadly ellipsoidal or spherical and consists of a fixed number of cells, usually 16 in mature individuals (rarely 4, 8 or 32). The cells are located at periphery of the coenobium and separated from each other by being embedded in a gelatinous matrix. The cell body is lens-shaped or hemispherical when mature, with two equal flagella. The chloroplast is dish- or bowl-shaped. Pyrenoids may be absent or present (located at the base of the chloroplast); eyespots are present, with eyespots in anterior cells larger than those in posterior cells.[1] The nucleus is centrally located[3] and there may be two contractile vacuoles at the base of each flagella, or several scattered contractile vacuoles.[1]
Volvulina reproduces both asexually and sexually. In asexual reproduction, each cell of the colony develops into a daughter colony through successive cell divisions, and then subsequent colony inversion. Sexual reproduction is isogamous.[1]
Species
[edit]Three species of Volvulina are well-characterized: Volvulina steinii, Volvulina pringsheimii, and Volvulina compacta.[1] The three species differ from each other in morphology, namely: the shape of the cells and whether they are contiguous, and the presence or location of pyrenoids.[4] In addition to these three species, there is also Volvulina playferiana which is poorly described and may be an immature form of V. steinii,[4] and Volvulina boldii which is a nomen nudum.[5]
Phylogeny
[edit]Molecular phylogenetic studies show that Volvulina is paraphyletic with respect to Pandorina:[6][7][8]
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References
[edit]- ^ a b c d e f g Guiry, M.D.; Guiry, G.M. "Volvulina Playfair, 1915". AlgaeBase. University of Galway. Retrieved 2025-04-04.
- ^ See the NCBI webpage on Volvulina. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
- ^ Protist Images: Volvulina.
- ^ a b Nozaki, H.; Kuroiwa, T. (1990). "Volvulina compacta sp. nov. (Volvocaceae, Chlorophyta) from Nepal". Phycologia. 29 (4): 410–417. Bibcode:1990Phyco..29..410N. doi:10.2216/i0031-8884-29-4-410.1.
- ^ Nakada, T.; Tomita, M.; Nozaki, H. (2010). "Volvulina compacta (Volvocaceae, Chlorophyceae), new to Japan, and its phylogenetic position". Journal of Japanese Botany. 85. doi:10.51033/jjapbot.85_6_10256.
- ^ Lindsey, Charles Ross; Rosenzweig, Frank; Herron, Matthew D. (2021). "Phylotranscriptomics points to multiple independent origins of multicellularity and cellular differentiation in the volvocine algae". BMC Biology. 19 (1): 182. Bibcode:2021BMCB...19..182L. doi:10.1186/s12915-021-01087-0. PMC 8408923. PMID 34465312.
- ^ Ma, Xiaoya; Shi, Xuan; Wang, Qiuping; Zhao, Mengru; Zhang, Zhenhua; Zhong, Bojian (2023). "A Reinvestigation of Multiple Independent Evolution and Triassic–Jurassic Origins of Multicellular Volvocine Algae". Genome Biology and Evolution. 15 (8). doi:10.1093/gbe/evad142. PMC 10410301. PMID 37498572.
- ^ Lindsey, Charles Ross; Knoll, Andrew H.; Herron, Matthew D.; Rosenzweig, Frank (2024-04-10). "Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae". BMC Biology. 22 (1): 79. Bibcode:2024BMCB...22...79L. doi:10.1186/s12915-024-01878-1. ISSN 1741-7007. PMC 11007952. PMID 38600528.
External links
[edit]- Volvulina - Description with pictures
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