Members of Oocystaceae are common microalgae in freshwater habitats, and a few occur in semi-saline.[3]
Description
Members of the family Oocystaceae consist of cells which are solitary or found in colonies of 2, 4, 8, 16, or more. Cells are typically oval to ellipsoidal, sometimes spherical, rhomboid, spindle-shaped or lemon-shaped. Cells, when colonial, may be arranged into coenobia or pseudofilaments. Cells contain multiple chloroplasts of varying morphology—usually parietal, sometimes radial or spongiform, and with or without a pyrenoid. The cell wall is multilayered, often thickened at the poles, and may be smooth, warty or covered in spines.[4]
A uniting ultrastructural feature of all members of this family is the multiple-layered cell wall, with the cellulose fibrils in each layer organized perpendicularly to those of adjoining layers.[4]
Reproduction occurs asexually and via the production of multiple autospores. The daughter cells often remain in the expanded mother cell wall.[4]
Classification
Traditionally, genera and species within Oocystaceae have been separated from each other based on morphology. However, microalgae typically have very few morphological features for classification, and the morphological features may have evolved more than once. Currently, molecular phylogenetics form the basis of species and genera.[4]
Phylogenetic studies suggest the following relationships (note the polyphyly or paraphyly of several genera, in particular the type genus Oocystis):[5][4][3][6][7][8][9]
The genera Tetrastrum and Planctonema are incertae sedis taxa: they are sister to the rest of Oocystaceae and may be classified as such, but do not show the characteristic ultrastructure of Oocystaceae.[5]
^ abLiu, Xudong; Zhu, Huan; Song, Huiyin; Wang, Qinghua; Xiong, Xiong; Wu, Chenxi; Liu, Guoxiang; Hu, Zhengyu (2018). "Euchlorocystis gen. nov. and Densicystis gen. nov., Two New Genera of Oocystaceae Algae from High-altitude Semi-saline Habitat (Trebouxiophyceae, Chlorophyta)". Journal of Eukaryotic Microbiology. 65 (2): 200–210. doi:10.1111/jeu.12455. PMID28792654.
^ abcdefŠtenclová, Lenka (2013). Systematic revision of the family Oocystaceae (Thesis). České Budějovice: University of South Bohemia. p. 70.
^ abŠtenclová, Lenka; Fučíková, Karolina; Kaštovský, Jan; Pažoutová, Marie (2017). "Molecular and morphological delimitation and generic classification of the family Oocystaceae (Trebouxiophyceae, Chlorophyta)". Journal of Phycology. 53 (6): 1263–1282. Bibcode:2017JPcgy..53.1263S. doi:10.1111/jpy.12581. PMID28833138.
^Liu, Xudong; Wang, Qinghua; Zhu, Huan; Liu, Benwen; Rindi, Fabio; Liu, Guoxiang; Xie, Shulian; Hu, Zhengyu (2020). "Reticulocystis yunnanense gen. Et sp. Nov., a new member of freshwater Oocystaceae algae (Trebouxiophyceae, Chlorophyta)". European Journal of Phycology. 55 (4): 507–516. Bibcode:2020EJPhy..55..507L. doi:10.1080/09670262.2020.1751303.
^Mizobuchi, Aya; Handa, Shinji; Tsubota, Hiromi (2024). "Detailed observations of the life history and phylogenetic placements of the freshwater green alga Oocystaenium elegans (Oocystaceae, Trebouxiophyceae), with an emended description". Phycological Research. 72 (3): 215–223. doi:10.1111/pre.12559.
