Fritschiella aquatilis (Chaetophoraceae, Chlorophyta), a new freshwater green algae species from China

摘要

A new freshwater algal species proposed as Fritschiella aquatilis was found in a freshwater aquarium in China (Shanxi Province), floating on the surface and at the bottom of the water column. This new species is characterized by a tendergreen globular thallus with hairy morphology, composed of numerous small single celled filamentous branches. Most of its moprphologic characteristics are consistent with the description of Fritschiella. However, this new species differs from other members in this genus by the particular aquatic habitat and macroscopic thallus morphology (the only reported Fritschiella tuberosa Iyengar species is terrestrial). Concatenated sequences from 28S rDNA, 18S rDNA, and rbcL gene phylogenetic analyses of E. aquatilis were obtained to discuss taxonomic status. All phylogenetic trees yielded a Fritschiella Glade that included the sequence, and E. aquatilis formed an independent branch evidently distinguished from other species. The internal transcribed spacer secondary structure of the new species has some compensatory base changes (CBCs) and hemi-CBCs compared with E. tuberosa, particularly at the Helix 1 and Helix 2 ends. Thus, the results of morphological and molecular characteristics support that E. aquatilis should be recognized as a new species. This new alga increases the total number of recognized Fritschiella species, and the habitat circumscription of the genus Fritschiella has been expanded to include terrestrial and aquatic habitats.