Morphological examination and phylogenetic position of two newly recorded freshwater Cryptomonas species (Cryptophyceae) from China

Two freshwater cryptomonads, Cryptomonas obovata Skuja and Cryptomonas curvata Ehrenberg, are reported for the first time in China. Identification was based on light microscopy and scanning electron microscopy. Cryptomonas obovata was characterized by its obovoid cell shape, lobed cell subapex, and a large number of starch grains. Cryptomonas curvata was characterized by its sigmoid cell shape, rostrate cell apex, and numerous pyrenoids. Nuclear and nucleomorph small subunit rDNA phylogenetic analyses revealed Cryptomonas curvata collected from China was very similar to C. curvata strains cultivated in Germany, and the closest relative of C. obovata was found to be C. pyrenoidifera Geitler. Controversially, some quite morphologically different members of the genus Cryptomonas Ehrenberg were clustered into the same group in phylogeny analyses, which emphasized the complexity of the genus Cryptomonas.Two freshwater cryptomonads, Cryptomonas obovata Skuja and Cryptomonas curvata Ehrenberg, are reported for the first time in China. Identification was based on light microscopy and scanning electron microscopy. Cryptomonas obovata was characterized by its obovoid cell shape, lobed cell subapex, and a large number of starch grains. Cryptomonas curvata was characterized by its sigmoid cell shape, rostrate cell apex, and numerous pyrenoids. Nuclear and nucleomorph small subunit rDNA phylogenetic analyses revealed Cryptomonas curvata collected from China was very similar to C. curvata strains cultivated in Germany, and the closest relative of C. obovata was found to be C. pyrenoidifera Geitler. Controversially, some quite morphologically different members of the genus Cryptomonas Ehrenberg were clustered into the same group in phylogeny analyses, which emphasized the complexity of the genus Cryptomonas