Similarly to the case above, we propose a monotypic family Dictyococcaceae to accommodate the genus Dictyococcus with its only known species D. varians Gerneck. This alga is aquatic, multinucleate, polyplastidic with no pyrenoids, and reproduces asexually via naked biflagellate zoospores with equally long flagella (Starr 1955). The historical taxonomic confusion between Dictyococcus and Bracteacoccus was resolved in Fučíková et al. (2011a). The family Selenastraceae, represented here by Ankistrodesmus falcatus (Corda) Ralfs, Kirchneriella aperta, and Ourococcus multisporus, was recovered as monophyletic with good statistical support in all of our analyses, and requires Selleck PXD101 no taxonomic
update. This family contains aquatic, uninucleate, fusiform or sickle-shaped algae that are either solitary or colony-forming. Chloroplasts often contain pyrenoids that are either starch-covered or naked, often with thylakoid invaginations (Krienitz et al. 2001).
No flagellated stages have been reported in this BGJ398 family. The polyphyly of Ankistrodesmus and Monoraphidium was demonstrated in both Krienitz et al. (2001) and Fawley et al. (2006), but formal revisions have yet to be made. Other representatives of the family are Selenastrum, Podohedriella, Quadrigula, and Raphidocelis. The monophyly of the aquatic and coenobial Hydrodictyaceae was consistently recovered in our analyses. This family was treated in detail by Buchheim et al. (2005), who erected several new genera. More recently, McManus and Lewis (2011) examined this family, emphasizing the genus Pediastrum, with the use of both molecular
analyses and inspection of surface structures of many taxa using SEM. The status of the type genus has not yet been resolved, and Hydrodictyon selleck screening library currently remains nested within Pediastrum. Hydrodictyaceae have a single plastid and pyrenoid per cell (with the exception of Hydrodictyon, which has many pyrenoids and a reticulate plastid), multiple nuclei, and they reproduce asexually via autospores or zoospores, or sexually via isogamous biflagellate gametes. The development of flagellated cells of Pediastrum was described by Hawkins and Leedale (1971), and their ultrastructure by Wilcox and Floyd (1988). Scenedesmaceae contains numerous coenobial species of Desmodesmus, Neodesmus, and especially Scenedesmus, although some representatives of the last named genus are only known in solitary coccoid form (e.g., S. rotundus L. A. Lewis & Flechtner used in the present study). Other genera in this family are either coenobial (e.g., Coelastrum, Hariotina) or solitary (e.g., Scotiellopsis) and often have elaborate cell wall ornamentation (Kalina and Punčochářová 1987). Scenedesmacean algae generally have one nucleus and a single plastid with a pyrenoid in each cell, and reproduce asexually via autospores or zoospores, or rarely sexually via isogamy (Cain and Trainor 1976).