Flavoaurantia, a New Genus of the Chlorobotryaceae (eustigmatales, Eustigmatophyceae) with the Single Species, Flavoaurantia Irregularis

An algal strain with the morphological characteristics of the Eustigmatophyceae was isolated from a small pond in Itasca State Park, Minnesota, USA. Phylogenetic analyses of the DNA sequences from the nuclear 18S rDNA and the plastid rbcL loci both placed the strain in the order Eustigmatales and family Chlorobotryaceae. The new strain was not clearly allied with any lineage within the Chlorobotryaceae. Morphological features as determined by both light microscopy and transmission electron microscopy were typical for the Eustigmatales, except for the presence of an irregular surface of the cell wall (including the presence of stipitate or digitate projections on some cells) and the production of yellow-orange inclusions in the cytoplasm of cells in stationary-phase cultures. Upon transfer to fresh media, these inclusions are subsequently expunged from the cells during autosporulation. Based on these features and the results of phylogenetic analysis, we describe Flavoaurantia irregularis gen. et sp. nov.