Fottea X:X | DOI: 10.5507/fot.2026.005

Three novel species of Microglena (Chlamydomonadales, Chlorophyceae) from China revealed by an integrative approach

Yangliang Chen1, Qingyu Dai1, 2, Benwen Liu1, Huan Zhu1, Guoxiang Liu1
1 Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
2 University of Chinese Academy of Sciences, Beijing 100039, China

The taxonomic status of Microglena as a genus within Chlamydomonadales was reconfirmed. Many strains previously assigned to Chlamydomonas have been reclassified as members of Microglena, and new species continue to be described under this genus. In this study, we investigated three strains isolated from China using an integrative approach. Phylogenetic analyses based on 18S and ITS rDNA sequences, combined with comparisons of compensatory base changes (CBCs) for the conserved regions of ITS-2 secondary structure revealed that the three strains represent three independent species included in Microglena, and they are distinct from all previously described Microglena species, as well as from two closely related strains SAG 96.80 and SAG 22.95. Furthermore, morphological comparisons demonstrated that none of the three strains match known species sharing similar features. . Based on these results, three new Microglena species, including one lacking pyrenoids, are described here. Our results enrich the understanding of morphological diversity within Microglena, especially regarding the loss of pyrenoids.

Keywords: 18S rDNA, ITS-2 rDNA, Chlamydomonadales, Microglena monadinia, molecular phylogeny, morphology, new species

Received: December 2, 2025; Revised: April 2, 2026; Accepted: May 4, 2026; Prepublished online: September 9, 2026 

Share...
Download citation
  • BibTeX (.bib)
  • Bookends (.ris)
  • EasyBib (.ris)
  • EndNote (.enw)
  • EndNote 8 (.xml)
  • ISI WoS (.isi)
  • Medlars (.medlars)
  • Mendeley (.ris)
  • MODS (.xml)
  • Papers (.ris)
  • RefWorks (.txt)
  • RefManager (.ris)
  • RIS (.ris)
  • MS Word (.xml)
  • Zotero (.ris)
    • Open full article

    References

    1. Brown, R. M., & Bold, H. C. (1964). Comparative studies of the algal genera Tetracystis and Chlorococcum. University of Texas Publication 6417.
    2. Buchheim, M. A., Michalopulos, E. A., & Buchheim, J. A. (2001). Phylogeny of the Chlorophyceae with special reference to the Sphaeropleales: A study of 18S and 26S rDNA data. Journal of Phycology, 37(5), 819-835. Go to original source...
    3. Capella-Gutiérrez, S., Silla-Martínez, J. M., & Gabaldón, T. (2009). trimAl: A tool for automated alignment trimming in large-scale phylogenetic analyses. Bioinformatics, 25(15), 1972-1973. Go to original source...
    4. Demchenko, E., Mikhailyuk, T., Coleman, A. W., & Pröschold, T. (2012). Generic and species concepts in Microglena (previously the Chlamydomonas monadina group) revised using an integrative approach. European Journal of Phycology, 47(3), 264-290. Go to original source...
    5. Eddie, B., Krembs, C., & Neuer, S. (2008). Characterization and growth response to temperature and salinity of psychrophilic, halotolerant Chlamydomonas sp. ARC isolated from Chukchi Sea ice. Marine Ecology Progress Series, 354, 107-117. Go to original source...
    6. Ehrenberg, C. G. (1832). Über die Entwickelung und Lebensdauer der Infusionsthiere; nebst ferneren Beiträgen zu einer Vergleichung ihrer organischen Systeme. Abhandlungen der Königlichen Akademie der Wissenschaften, Berlin, 1831, 1-154.
    7. Ehrenberg, C. G. (1834). Dritter Beitrag zur Erkenntnis großer Organisation in der Richtung des kleinsten Raumes. Abhandlungen der Königlichen Akademie der Wissenschaften, Berlin, 1833, 145-336.
    8. Ettl, H. (1965). Beitrag zur Kenntnis der Morphologie der Gattung Chlamydomonas Ehrenberg. Archiv für Protistenkunde, 108, 271-420.
    9. Ettl, H. (1970). Die Gattung Chloromonas Gobi emend. Wille (Beihefte zur Nova Hedwigia, Vol. 34). Nova Hedwigia. Go to original source...
    10. Ettl, H. (1976). Die Gattung Chlamydomonas Ehrenberg (Beihefte zur Nova Hedwigia, Vol. 49). Nova Hedwigia.
    11. Ettl, H. (1978). Xanthophyceae, 1. Teil. In H. Ettl, J. Gerloff, & H. Heynig (Eds.), Süßwasserflora von Mitteleuropa (Vol. 3, No. 1). Gustav Fischer.
    12. Ettl, H. (1983). Chlorophyta I. Phytomonadia. In H. Ettl, J. Gerloff, & D. Mollenhauer (Eds.), Süßwasserflora von Mitteleuropa (Vol. 9). Gustav Fischer.
    13. Ettl, H., & Gärtner, G. (1987). Taxonomic and nomenclatural changes and descriptions of new taxa of the Tetrasporales, Chlorococcales and Gloeodendrales (Chlorophyta, Chlamydophyceae and Chlorophyceae). Nova Hedwigia, 44, 509-517. Go to original source...
    14. Fritsch, F. E., & John, R. P. (1942). An ecological and taxonomic study of the algae of British soils. II. Consideration of the species observed. Annals of Botany, 6(3), 371-395. Go to original source...
    15. Fulneèková, J., Hasíková, T., Fajkus, J., Luke¹ová, A., Eliá¹, M., & Sýkorová, E. (2012). Dynamic evolution of telomeric sequences in the green algal order Chlamydomonadales. Genome Biology and Evolution, 4(3), 248-264. Go to original source...
    16. Gerloff, J. (1940). Beiträge zur Kenntnis der Variabilität und Systematik der Gattung Chlamydomonas. Archiv für Protistenkunde, 94, 311-502.
    17. Guindon, S., Dufayard, J.-F., Lefort, V., Anisimova, M., Hordijk, W., & Gascuel, O. (2010). New algorithms and methods to estimate maximum-likelihood phylogenies, assessing the performance of PhyML 3.0. Systematic Biology, 59(3), 307-321. Go to original source...
    18. Hoshaw, R. W., & Rosowski, J. R. (1973). Isolation and purification 3: Methods for microscopic algae. In J. R. Stein (Ed.), Handbook of phycological methods. Culture methods and growth measurements (pp. 53-67). Cambridge University Press.
    19. Kalyaanamoorthy, S., Minh, B. Q., Wong, T. K. F., von Haeseler, A., & Jermiin, L. S. (2017). ModelFinder: Fast model selection for accurate phylogenetic estimates. Nature Methods, 14(6), 587-589. Go to original source...
    20. Katoh, K., & Standley, D. M. (2013). MAFFT multiple sequence alignment software version 7: Improvements in performance and usability. Molecular Biology and Evolution, 30(4), 772-780. Go to original source...
    21. Klebs, G. A. (1896). Ueber die Fortpflanzungs-Physiologie der niederen Organismen, der Protobionten. Specieller Theil. Die Bedingungen der Fortpflanzung bei einigen Algen und Pilzen. Gustav Fischer.
    22. Kumar, S., Stecher, G., Suleski, M., Sanderford, M., Sharma, S., & Tamura, K. (2024). MEGA12: Molecular Evolutionary Genetics Analysis version 12 for adaptive and green computing. Molecular Biology and Evolution, 41(12), Article msae263. Go to original source...
    23. Leya, T. (2004). Feldstudien und genetische Untersuchungen zur Kryophilie der Schneealgen Nordwestspitzbergens. Shaker.
    24. Liu, C., Huang, X., Wang, X., Zhang, X., & Li, G. (2006). Phylogenetic studies on two strains of Antarctic ice algae based on morphological and molecular characteristics. Phycologia, 45(2), 190-198. Go to original source...
    25. Lund, J. W. G. (1947). Observations on soil algae III. Species of Chlamydomonas Ehr. in relation to variability within the genus. New Phytologist, 46(2), 185-194. Go to original source...
    26. Massalski, A., Mrozinska, T., & Olech, M. (2001). Ultrastructural observations on five pioneer soil algae from ice denuded areas (King George Island, West Antarctica). Polar Bioscience, 14, 61-70.
    27. Minh, B. Q., Schmidt, H. A., Chernomor, O., Schrempf, D., Woodhams, M. D., von Haeseler, A., & Lanfear, R. (2020). IQ-TREE 2: New models and efficient methods for phylogenetic inference in the genomic era. Molecular Biology and Evolution, 37(5), 1530-1534. Go to original source...
    28. Moewus, F. (1931). Neue Chlamydomonaden. Archiv für Protistenkunde, 75, 284-296.
    29. Müller, T., Philippi, N., Dandekar, T., Schultz, J., & Wolf, M. (2007). Distinguishing species. RNA, 13(9), 1469-1472. Go to original source...
    30. Nakada, T., Misawa, K., & Nozaki, H. (2008). Molecular systematics of Volvocales (Chlorophyceae, Chlorophyta) based on exhaustive 18S rRNA phylogenetic analyses. Molecular Phylogenetics and Evolution, 48(1), 281-291. Go to original source...
    31. Nakada, T., & Tomita, M. (2014). Light microscopy and phylogenetic analyses of Chlamydomonas species (Volvocales, Chlorophyceae). II. Molecular phylogeny, secondary structure of ITS-2, cell morphology, and nomenclature of Microglena opisthopyren and M. media comb. nov. Acta Phytotaxonomica et Geobotanica, 65(2), 67-73.
    32. Nakada, T., Takahashi, S., & Tomita, M. (2018). Microglena redcarensis sp. nov. (Volvocales, Chlorophyceae), a brackish water chlamydomonad with contractile vacuoles. Phycological Research, 66(4), 310-317. Go to original source...
    33. Nakazawa, A., & Nozaki, H. (2004). Phylogenetic analysis of the tetrasporalean genus Asterococcus (Chlorophyceae) based on 18S ribosomal RNA gene sequences. Journal of Japanese Botany, 79(4), 255-261.
    34. Nozaki, H., Misumi, O., & Kuroiwa, T. (2003). Phylogeny of the quadriflagellate Volvocales (Chlorophyceae) based on chloroplast multigene sequences. Molecular Phylogenetics and Evolution, 29(1), 58-66. Go to original source...
    35. Nozaki, H., Nakada, T., & Watanabe, S. (2010). Evolutionary origin of Gloeomonas (Volvocales, Chlorophyceae), based on ultrastructure of chloroplasts and molecular phylogeny. Journal of Phycology, 46(1), 195-200. Go to original source...
    36. Pascher, A. (1927). Die Süsswasser-Flora Deutschlands, Österreichs und der Schweiz. Heft 4: Volvocales = Phytomonadinae. Gustav Fischer.
    37. Pascher, A. (1930). Neue Volvocalen (Polyblepharidinen-Chlamydomonadinen). Archiv für Protistenkunde, 69, 103-146.
    38. Pawlowski, J., Holzmann, M., Fahrni, J. F., & Hallock, P. (2001). Molecular identification of algal endosymbionts in large miliolid foraminifera: 1. Chlorophytes. Journal of Eukaryotic Microbiology, 48(3), 362-367. Go to original source...
    39. Reuter, J. S., & Mathews, D. H. (2010). RNAstructure: Software for RNA secondary structure prediction and analysis. BMC Bioinformatics, 11, Article 129. Go to original source...
    40. Ronquist, F., Teslenko, M., van der Mark, P., Ayres, D. L., Darling, A., Höhna, S., Larget, B., Liu, L., Suchard, M. A., & Huelsenbeck, J. P. (2012). MrBayes 3.2: Efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic Biology, 61(3), 539-542. Go to original source...
    41. Siebert, S., & Backofen, R. (2005). MARNA: Multiple alignment and consensus structure prediction of RNAs based on sequence structure comparisons. Bioinformatics, 21(16), 3352-3359. Go to original source...
    42. Skuja, H. (1956). Taxonomische und biologische Studien über das Phytoplankton schwedischer Binnengewässer. Nova Acta Regiae Societatis Scientiarum Upsaliensis, 19(3), 1-404.
    43. Stein, F. (1878). Der Organismus der Infusionsthiere nach eigenen Forschungen in systematischere Reihenfolge bearbeitet. III. Abtheilung. Die Naturgeschichte der Flagellaten oder Geisselinfusorien. Verlag von Wilhelm Engelmann.
    44. Trentin, R., Negrisolo, E., Moschin, E., Veronese, D., Cecchetto, M., & Moro, I. (2022). Microglena antarctica sp. nov. a new antarctic green alga from Inexpressible Island (Terra Nova Bay, Ross Sea) revealed through an integrative approach. Diversity, 14(5), Article 337. Go to original source...
    45. Watanabe, M. M., & Hiroki, M. (1997). NIES-collection. List of strains: Microalgae and protozoa (5th ed.). National Institute for Environmental Studies.
    46. Watanabe, S., & Lewis, L. A. (2017). Phylogenetic interpretation of light and electron microscopic features of selected members of the phylogroup Moewusinia (Chlorophyceae), with new generic taxonomy. Phycologia, 56(3), 329-353. Go to original source...
    47. Wolf, M., Friedrich, J., Dandekar, T., & Müller, T. (2005). CBCAnalyzer: Inferring phylogenies based on compensatory base changes in RNA secondary structures. In Silico Biology, 5(3), 291-294. Go to original source...

    Return