2024 Volume 99 Issue 1 Pages 25-37
Chamaesiphon bursiformis M.Fukuoka, Kitano & Hidek.Suzuki is described as a new freshwater benthic cyanobacterium discovered in the springs of Hokkaido and north and central Honshu of Japan. This species is characterized by a colony consisting of cells arranged in either parallel or radial patterns, surrounded by a thick sheath and a sac-like thallus, which has not been reported in any other Chamaesiphon species. The genetic distance of the 16S rRNA gene and the 16S-23S rRNA internal transcribed spacer (ITS) region between C. bursiformis and other Chamaesiphon species was above the threshold for interspecific differences. In addition, the secondary structures of the 16S-23S rRNA ITS region of C. bursiformis were found to have unique structures not found in other species of Chamaesiphon. These characteristics clearly distinguish C. bursiformis from the other species in Chamaesiphon. Chamaesiphon bursiformis has been observed in the springs with low water temperatures at the foot of large stratovolcanoes such as Mt. Chokaisan. There were no morphological and genetic differences among the samples obtained from some Japanese localities.
